Why My Car Won't Start Up
Far too often when we get vehicles that do not start, we realize that most people do not understand the difference between a no start condition from a bad battery, or a no start condition from a bad fuel pump. With this information below, we hope to clear up any confusion on the matter and help educate our customers so they become better informed about their vehicles.
Step by step car no start troubleshooting guide:
Common Questions Answered:
Why won't my car start?
Car Engine Cranks But will not Start?
Car Just Makes Click noise but will not start?
Car Won't Start After Jump Start?
Car Won't Start, No Crank?
Battery is Good But Car Won't Start?
Find what are the common reasons a car won't start and what to do to get your car up and running again.
As a rough guile line problems will be battery, alternator and starter. These are the most common causes of a car or truck failing to start.
If you still have any unresolved vehicle problems or questions, you can ask your problem in comments section.
Top Reasons a Car Won't Start
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Car Won't Start, Clicking Noise
My 1997 Jeep Grand Cherokee Limited 6 cyl will not start after sitting more than 4 hours. Before I even put the key into the ignition I hear a clicking noise on the right side may be under hood may be under the dash.
Battery is drained to nothing (no lights inside car or out) once I put a charge on it, it will start, clicking noise goes away. I drive it and then when I park it and shut it off for 4 or more hours the same thing happens again. Battery tested good, as did alternator. Seems as though whatever is making the clicking noise while car is not even on is draining the battery in a matter of 4 hours.
Answer: The most likely reason your car won't start is due to a bad relay. This clicking noise is most likely one of your relays turning on and off. When it is on it is using battery power and this is probably what is running your battery down.
Look for the fuse relay block under your hood. You should be looking for a small black box. The one that is clicking is the one that is most likely bad. You should be able to just buy a new one and replace it.
Answer: The most likely reason your car won't start is due to a bad relay. This clicking noise is most likely one of your relays turning on and off. When it is on it is using battery power and this is probably what is running your battery down.
Look for the fuse relay block under your hood. You should be looking for a small black box. The one that is clicking is the one that is most likely bad. You should be able to just buy a new one and replace it.
Car Cranks But Won't Start
I have a 1991 Toyota Camry 4 cyl california emmisions that is getting no spark. Battery seems good, the engines cranks but car won't start. Removed #1 plug wire, installed plug in wire and grounded threads to valve cover and saw no spark when engine was cranked. Timing belt replaced last year, remanufactured distributer installed 4 months ago along with new plugs, plug wires, distributer cap and rotor.
Have measured 12 VDC at coil, so far no problems with fuses or relays evident. Checked diagnostic port and received error from chk engine light 2 short blinks then a pause and then 4 short blinks (ECU failure). Replaced ignitor (ECU) with a used identical replacement. After changing ignitor (ECU) and checking diagnostic port the chk engine light would blink steady at a quick rate indicating no trouble.
Still no spark and my car won't start, please help.
Answer: For your car, code 24 indicates a problem in the Intake Air Temperature Sensor circuit. This could be the IAT sensor itself, it could be your car's ECU, or it could even be a problem in the wiring between the ECU and the IAT.
The most likely cause is a bad sensor, but it is possible that the ECU is bad as well. You mentioned that you replaced the Ignitor. This is not the ECU. Your car's computer is located behind the center of your instrument panel. Most likely it is fine, but it is possible that it is bad.
There are a couple of things that cause no starts that you might want to have tested or replaced. They are the Camshaft Position Sensor (CMP) and the Crankshaft Position Sensor (CKP). These sensors are what the computer uses to calculate timing, spark and fuel injector pulse width. If one of theses sensors were bad it could cause a no start.
Answer: For your car, code 24 indicates a problem in the Intake Air Temperature Sensor circuit. This could be the IAT sensor itself, it could be your car's ECU, or it could even be a problem in the wiring between the ECU and the IAT.
The most likely cause is a bad sensor, but it is possible that the ECU is bad as well. You mentioned that you replaced the Ignitor. This is not the ECU. Your car's computer is located behind the center of your instrument panel. Most likely it is fine, but it is possible that it is bad.
There are a couple of things that cause no starts that you might want to have tested or replaced. They are the Camshaft Position Sensor (CMP) and the Crankshaft Position Sensor (CKP). These sensors are what the computer uses to calculate timing, spark and fuel injector pulse width. If one of theses sensors were bad it could cause a no start.
What’s causing the no-start? All engines require three things to start and run: spark, fuel, and compression. If any one of these isn’t there, you aren’t going anywhere.
Symptom:Engine Cranks but won’t Start
Probable Causes:
Chances are the Check Engine Light is not on, but you may find any of the following codes:
No spark due to a bad crank position sensor, a faulty ignition module or PCM, a problem in the ignition circuit (ignition switch, antitheft system, wiring, etc.), a faulty park/neutral safety switch, a bad ignition coil (only on engines with a single coil ignition), or wet plugs or plug wires (did it rain last night, did you just wash the engine?)
A less common cause is a worn starter that draws so many amps while cranking the engine that there’s not enough juice left to adequately power the ignition system and fuel injectors. Contributing factors might be a weak battery and/or loose or corroded battery cables.
No fuel because of a dead fuel pump, bad fuel pump relay, blown fuel pump fuse, plugged fuel filter or line, or failed PCM injector driver circuit or injector power supply relay. Or, the fuel tank might be empty (don’t believe what the gauge is telling you), or the fuel tank might contain contaminated fuel (water or too much alcohol) or the wrong type of fuel (whoops, somebody put in diesel instead of gasoline).
No compression because the timing belt or chain is broken, the timing belt or chain is loose and jumped out of time, or the overhead camshaft has snapped. A powerful scantool like AutoTap Express DIY can help isolate the root cause.
The first step is to determine if it’s a spark, fuel, or compression problem. Here’s a quick way to find out which of the three is missing. Remove a plug wire, insert a Phillips screwdriver or spare plug piece of bare wire into the plug wire boot and place the end near the engine block (do not hold the plug wire while cranking the engine unless you want a shocking experience). If there’s a spark when the engine is cranked, it has ignition. The problem is either fuel or compression. If the engine has an overhead cam with a timing belt, loosen the cover over the timing belt and check the belt. If the belt is okay, the problem is no fuel. Listen for the electric fuel pump in the fuel tank to make a buzzing noise when the ignition is turned on (you may have to open the gas cap to hear it). You won’t hear anything if the pump has died. Diagnostics can now be focused on the fuel pump circuit to determine if the pump, relay or wiring is causing the no start. If the relay has voltage but the pump isn’t running, you’ll probably have to drop the fuel tank to check the wiring connector at the pump. If the problem is no spark, anything in the ignition circuit that creates the spark may be at fault. Use your AutoTap Express DIY to look for an RPM signal from the Crankshaft Position sensor while cranking the engine. A bad Crankshaft Position sensor is a common cause of no starts. The signal from this sensor goes to the PCM or ignition module that switches the ignition coil(s) on and off. If you have an RPM signal, a bad ignition module or PCM may not be switching the coil(s) on and off. Using a voltmeter, check for voltage at the coils with the key on and while cranking the engine. The voltage should be switching on and off. In ignition systems with a single coil and distributor, a bad coil or a cracked distributor cap or rotor can prevent the spark plugs from firing. On multi-coil, distributorless ignition systems and coil-on-plug systems; one coil failure may cause an engine to misfire, but it won't prevent it from starting. What’s causing the no-start? All engines require three things to start and run: spark, fuel and compression. If any one of these isn’t there, you aren’t going anywhere.
I tried starting my car after few days and now it just cranks but not start.Also i checked engine coolant level and its empty.Is no coolant related to no start.Please help?
Symptom:Engine Cranks but won’t Start
Probable Causes:
- Fuel Pump (P0230 to P0233)
- PCM (P0600 to P0606)
- Crank Sensor (P0355 to P0399)
- Fuel Pressure (P0190 to P0194)
Chances are the Check Engine Light is not on, but you may find any of the following codes:
- P0230 to P0233 Fuel Pump codes
- P0600 to P0606 PCM related codes
- P0335 to P0339 Crank Sensor codes
- P0190 to P0194 Fuel Pressure Sensor codes
No spark due to a bad crank position sensor, a faulty ignition module or PCM, a problem in the ignition circuit (ignition switch, antitheft system, wiring, etc.), a faulty park/neutral safety switch, a bad ignition coil (only on engines with a single coil ignition), or wet plugs or plug wires (did it rain last night, did you just wash the engine?)
A less common cause is a worn starter that draws so many amps while cranking the engine that there’s not enough juice left to adequately power the ignition system and fuel injectors. Contributing factors might be a weak battery and/or loose or corroded battery cables.
No fuel because of a dead fuel pump, bad fuel pump relay, blown fuel pump fuse, plugged fuel filter or line, or failed PCM injector driver circuit or injector power supply relay. Or, the fuel tank might be empty (don’t believe what the gauge is telling you), or the fuel tank might contain contaminated fuel (water or too much alcohol) or the wrong type of fuel (whoops, somebody put in diesel instead of gasoline).
No compression because the timing belt or chain is broken, the timing belt or chain is loose and jumped out of time, or the overhead camshaft has snapped. A powerful scantool like AutoTap Express DIY can help isolate the root cause.
The first step is to determine if it’s a spark, fuel, or compression problem. Here’s a quick way to find out which of the three is missing. Remove a plug wire, insert a Phillips screwdriver or spare plug piece of bare wire into the plug wire boot and place the end near the engine block (do not hold the plug wire while cranking the engine unless you want a shocking experience). If there’s a spark when the engine is cranked, it has ignition. The problem is either fuel or compression. If the engine has an overhead cam with a timing belt, loosen the cover over the timing belt and check the belt. If the belt is okay, the problem is no fuel. Listen for the electric fuel pump in the fuel tank to make a buzzing noise when the ignition is turned on (you may have to open the gas cap to hear it). You won’t hear anything if the pump has died. Diagnostics can now be focused on the fuel pump circuit to determine if the pump, relay or wiring is causing the no start. If the relay has voltage but the pump isn’t running, you’ll probably have to drop the fuel tank to check the wiring connector at the pump. If the problem is no spark, anything in the ignition circuit that creates the spark may be at fault. Use your AutoTap Express DIY to look for an RPM signal from the Crankshaft Position sensor while cranking the engine. A bad Crankshaft Position sensor is a common cause of no starts. The signal from this sensor goes to the PCM or ignition module that switches the ignition coil(s) on and off. If you have an RPM signal, a bad ignition module or PCM may not be switching the coil(s) on and off. Using a voltmeter, check for voltage at the coils with the key on and while cranking the engine. The voltage should be switching on and off. In ignition systems with a single coil and distributor, a bad coil or a cracked distributor cap or rotor can prevent the spark plugs from firing. On multi-coil, distributorless ignition systems and coil-on-plug systems; one coil failure may cause an engine to misfire, but it won't prevent it from starting. What’s causing the no-start? All engines require three things to start and run: spark, fuel and compression. If any one of these isn’t there, you aren’t going anywhere.
Car Won't Start But Turns Over
I have a 1993 Ford Mustang convertible. It seems as if the gas isn't quite getting to the engine. Everything is turning over, but my car won't start. There is enough gas in the tank.
Answer: The first thing you need to do is determine if it is a fuel problem or a spark problem. If you don't have one you will need to buy an inline spark tester and a fuel pressure tester that will fit your car.
Test the fuel pressure and see if there is spark. After you know which of those you don't have, you will know whether to start checking fuel system related items or to look at the ignition system.
In your case, the most common reason your car won't start is probably due to a fuel related problem such as a bad fuel pump.
Answer: The first thing you need to do is determine if it is a fuel problem or a spark problem. If you don't have one you will need to buy an inline spark tester and a fuel pressure tester that will fit your car.
Test the fuel pressure and see if there is spark. After you know which of those you don't have, you will know whether to start checking fuel system related items or to look at the ignition system.
In your case, the most common reason your car won't start is probably due to a fuel related problem such as a bad fuel pump.
Car Engine Cranks But Will Not Turn Over
A car that cranks but won't start is a pretty good candidate for a failed fuel pump or a blown fuse for the fuel pump. There's a good possibility the Check Engine Light will *not* be on in this case. It would've been nice to now how old the car is and how many miles are on it. Old/high mileage car probably means a bad fuel pump.
When you turn the ignition key to the "ON" position (one click shy of the spring-loaded "START" position) you should hear the faint sound of the fuel pump run for a few seconds then turn off. The pump runs to build pressure in the fuel system for the start. Once the pressure is reached it will shut off. If you don't hear the pump run then check the fuse for it. The fuel pump is a high draw item and the fuse for it is located in the engine compartment with other high amperage draw circuits. The fuse box is usually located near one of the wheel wells off to either side of the engine. It will be black plastic and usually has "FUSES" in raised letters on the cover. Pop the cover and use the "map" to find the correct fuse. Pull and examine. If you're lucky the fuse is blown and you'll need a new one of equal rating. Replacing the fuse should get you up and running.
If the fuse is fine and you didn't hear it run when selecting "ON" with the ignition key then it's a pretty good bet the fuel pump is toast. You can console yourself it didn't quit out on the freeway. With a dead fuel pump your car is dead in the water ...it'll need to be flat-bedded to the shop.
When you say you checked the coolant and found none ...I am assuming you mean in the plastic expansion tank. Yeah, you could have a leak but when was the last time you checked it?? Coolant will, over time, evaporate. Evaporate to the point where the expansion tank is empty. Before the first start of the day, engine cold, open the radiator cap and make sure the coolant is up the the bottom of the filler neck and put the radiator cap back on. Next, fill the expansion tank to the "COLD" line then drive it. Next morning check the fluid level again ...only this time just check the expansion tank. Fill the tank to the "COLD" line and drive. Keep doing this until the coolant level in the tank sits at the "COLD" level with the engine cold. And then check it at least once a week to make sure you don't have a leak in your system. Prior to each first start the coolant should be at the "COLD" mark.
Car Won't Start Sometimes, No Lights, No Radio
I just replaced the starter, battery, and alternator on my 1994 Nissan Sentra. Now my car won't start sometimes, and the dome light, radio and seat belt will not work. Please help
Answer: The most likely cause of your problem is a bad connection somewhere or even a new defective battery.
You should re-check all of your connections, especially your battery cable connections. Be sure they are clean and tight. If they are not it could cause this problem. Also check all of your other connections to be sure they are clean and tight.
You might even want to check all of the fuses. If the wrong wires touched you could just have a fuse blown.
Answer: The most likely cause of your problem is a bad connection somewhere or even a new defective battery.
You should re-check all of your connections, especially your battery cable connections. Be sure they are clean and tight. If they are not it could cause this problem. Also check all of your other connections to be sure they are clean and tight.
You might even want to check all of the fuses. If the wrong wires touched you could just have a fuse blown.
Car Won't Start After Jump Start
My car won't start one day so I jump started it and then it started making a loud clicking noise while I was driving it and while the engine idled.
Next day car started okay with no clicking noise, but the next time I tried to start it that day, it would not start. Again I tried to jump it, but it would not start. When turning the key in the ignition while trying to jump the car, there was a clicking noise.
Do you think this is a starter problem or could it be a broken timing belt? (1998 Mazda Millenia 2.5L)
Answer: The first thing you need to do is have your electrical system checked out. Your alternator might not be charging your battery the way it should or you could have a faulty battery.
Most auto parts stores will test the alternator and battery for free. Be sure to have them do a load test on your battery. Load testing is more accurate than just checking voltage as it shows how good the battery is when there is an electrical load put on it.
The clicking noise you are hearing is most likely from one or more relays turning on and off. Relays will do this when there is not enough voltage in the electrical system to keep them turned on. It is a classic symptom of a low voltage situation.
It is possible that this is a starter problem, but since you have relays that are clicking on and off it is probably not the starter. You could also have a problem with the starter solenoid, but that is also unlikely.
I think once you have your battery and alternator checked, you will find your problem. Keep in mind that you need to check your battery cables for corrosion and tightness. They need to be clean and tight in order for the alternator to be able to charge the battery.
The clicking noise you are hearing is most likely from one or more relays turning on and off. Relays will do this when there is not enough voltage in the electrical system to keep them turned on. It is a classic symptom of a low voltage situation.
It is possible that this is a starter problem, but since you have relays that are clicking on and off it is probably not the starter. You could also have a problem with the starter solenoid, but that is also unlikely.
I think once you have your battery and alternator checked, you will find your problem. Keep in mind that you need to check your battery cables for corrosion and tightness. They need to be clean and tight in order for the alternator to be able to charge the battery.
Car Won't Start, No Crank
My Jeep has a 4 liter engine and when I turn the key on I can hear the fuel pump come on but when I try to crank it nothing happens except the parking brake light in the dash comes on for as long as the key is in the start position.
This is the second time this has happened, and both times I started the jeep to move it out of the way and when I tried to start it again nothing happened. The first time it did this I let it sit for about 10 hours and every thing was fine. The second time it sat over night and still nothing happens when I try to start it. I hope it isn't too confusing and any info will help. Thanks. (1994 Jeep Grand Cherokee)
Answer: This sounds like some type of electrical problem. The first thing I would check is your battery cable connections. Be sure they are clean and tight. Then have your battery and alternator tested to be sure that they are working correctly and are not faulty. Most auto parts stores will provide this car won't start help for free.
After all of that is done, you need to see why it is not turning over by checking for power at the starter. Check for battery voltage at the large post on the starter solenoid at all times, then see if there is battery voltage at the small ignition terminal with the key in the start position.
If there is power at both of these terminals then you simply have a starter or solenoid problem. If you suspect this you can try giving the starter a couple good blows with a hammer when it won't turn over. Sometimes this will jar it free.
Answer: This sounds like some type of electrical problem. The first thing I would check is your battery cable connections. Be sure they are clean and tight. Then have your battery and alternator tested to be sure that they are working correctly and are not faulty. Most auto parts stores will provide this car won't start help for free.
After all of that is done, you need to see why it is not turning over by checking for power at the starter. Check for battery voltage at the large post on the starter solenoid at all times, then see if there is battery voltage at the small ignition terminal with the key in the start position.
If there is power at both of these terminals then you simply have a starter or solenoid problem. If you suspect this you can try giving the starter a couple good blows with a hammer when it won't turn over. Sometimes this will jar it free.
Battery is Good But Car Won't Start
I have a 1996 Cadillac Deville V8 with a 4.6L engine. My car won't start and I thought it was my battery so I bought a new one. Someone told me that it could be my starter or my ignition. How do i know what is the reason my car won't start and how do I fix it?
Answer: Your starting problem could indeed be caused by your starter or your ignition switch. If the engine turns over good, then it is not a problem with either of those things.
If it does not turn over (I'm assuming it does not), then the first thing to check is that your battery cables are clean and tight. I'm guessing that you have already done this since you replaced your battery, but you should re-check them just to be sure.
Answer: Your starting problem could indeed be caused by your starter or your ignition switch. If the engine turns over good, then it is not a problem with either of those things.
If it does not turn over (I'm assuming it does not), then the first thing to check is that your battery cables are clean and tight. I'm guessing that you have already done this since you replaced your battery, but you should re-check them just to be sure.
The next thing to check is to see if your dash lights come on when you turn your key on. If they do then most likely your ignition switch is just fine (but it still could be bad, it's just not likely). If they don't come on, then you either have a problem with your ignition switch or a wiring problem that is not letting power get to the ignition switch and starter.
Engine Won't Crank, No Lights, No Radio
I have a 1995 Chevy S10 with a 4.3L that I am having problems with. Two days ago the truck died and nothing would work. It wouldn't crank, the lights and radio won't work, nothing.
I took the alternator and had it checked, it was ok, when I put it back in it started right up again. I drove it home and then the next time I drove it the same thing happen. Someone told me the "ignition control module" may be bad. I am just looking for other suggestions.
Answer: This sounds more like a battery problem or maybe even a problem with your battery cables. The fact that nothing would come on tells me that there was something preventing any power from getting to the fuse block and the rest of the car.
The first thing I would to is check your battery cables. I would even clean them and then make sure they are tight. After that I would take it to an auto parts store to have them load test the battery. This will tell you if it is being caused by the battery.
I think you will find your problem in one of those areas. I really doubt that your ignition control module is bad because that would have nothing to do with the lights and radio not working. It is possible that it is an ignition switch problem, but that is not likely.
The first thing I would to is check your battery cables. I would even clean them and then make sure they are tight. After that I would take it to an auto parts store to have them load test the battery. This will tell you if it is being caused by the battery.
I think you will find your problem in one of those areas. I really doubt that your ignition control module is bad because that would have nothing to do with the lights and radio not working. It is possible that it is an ignition switch problem, but that is not likely.
Car Won't Start After Stalling
I have a 1993 Dodge Dakota 4x4 3.9l V6. It stalled and won't start. I replaced the fuel pump and fuel filter, replaced pump relay and auto shut down relay (ASD Relay) with new relays. Checked wiring from relay block on left wheel well also replaced cap and rotor and spark plugs what else should I check? Thanks
Answer: The first thing you need to do is determine whether your truck is not getting fuel, not getting spark or has bad compression. Usually random stalling is not caused by a compression problem but it is possible.
You will need a few tools to do this testing. You should start with a compression test. Be sure that all of the spark plugs are out, then disable the ignition system. Using acompression tester kit, check each cylinder to see if there are any that are low on compression.
The next thing you will need to do is get a fuel pressure tester for your fuel system. Be sure to get one that will work for your truck. Then simply hook into the fuel system and see what the pressure is.
To check spark, you will an inline spark tester. This type of tester hooks in between the spark plug wire and the spark plug. Then you just try to start the engine and see if the tester lights.
After all of these tests have been done you will have narrowed the problem down to one system instead of three. After you get it narrowed down, you can start looking at each component of the problematic system.
Keep in mind that there is a Technical Service Bulletin (TSB) for the distributor drive bushing wearing out. This could be the source of your problem as well. Also, ignition coils and the ignition pickup inside the distributor are common problems with these trucks.
Answer: The first thing you need to do is determine whether your truck is not getting fuel, not getting spark or has bad compression. Usually random stalling is not caused by a compression problem but it is possible.
You will need a few tools to do this testing. You should start with a compression test. Be sure that all of the spark plugs are out, then disable the ignition system. Using acompression tester kit, check each cylinder to see if there are any that are low on compression.
The next thing you will need to do is get a fuel pressure tester for your fuel system. Be sure to get one that will work for your truck. Then simply hook into the fuel system and see what the pressure is.
To check spark, you will an inline spark tester. This type of tester hooks in between the spark plug wire and the spark plug. Then you just try to start the engine and see if the tester lights.
After all of these tests have been done you will have narrowed the problem down to one system instead of three. After you get it narrowed down, you can start looking at each component of the problematic system.
Keep in mind that there is a Technical Service Bulletin (TSB) for the distributor drive bushing wearing out. This could be the source of your problem as well. Also, ignition coils and the ignition pickup inside the distributor are common problems with these trucks.
Car Won't Start, Clicking Noise, Battery Works
I have a 2006 Ford Explorer. The battery is fully charged and my car won't start. When I take the key out of the ignition there is a clicking sound coming from the run/start relay. What could be the problem?
Answer: To figure out why your car won't start, there are several things to check. The first is to see if your battery cables are clean and tight. It is very important that they are as just a little corrosion or a little looseness can cause this type of problem.
The next thing to do is have your battery load tested. Even though it is fully charged it can still be bad under a high load, like when you try to start it.
The next thing that could be causing it is your starter, relay or solenoid. Sometimes a relay will go bad and cause this type of problem. You can try to switch the relay that was doing the clicking with another relay to see if that will get it to start. If it does then you know that the relay was bad.
It is possible that you have a bad ignition switch as well but that is not as likely. I think you will find your problem with your battery, cables, connections or relays.
Answer: To figure out why your car won't start, there are several things to check. The first is to see if your battery cables are clean and tight. It is very important that they are as just a little corrosion or a little looseness can cause this type of problem.
The next thing to do is have your battery load tested. Even though it is fully charged it can still be bad under a high load, like when you try to start it.
The next thing that could be causing it is your starter, relay or solenoid. Sometimes a relay will go bad and cause this type of problem. You can try to switch the relay that was doing the clicking with another relay to see if that will get it to start. If it does then you know that the relay was bad.
It is possible that you have a bad ignition switch as well but that is not as likely. I think you will find your problem with your battery, cables, connections or relays.
Car Won't Start After Replacing O2 Sensors
I have a 1994 Camaro v6 and after replacing the top two o2 sensors I was able to drive it home just fine but when I went to start it up again it would only turn over for a second or two and die. Any suggestions?
Answer: If it did not do this before you replaced the O2 sensors, then you must have either forgotten to plug something back in or you might have hit something. The first thing to do is re-check everything that you might had removed or disconnected to do this job. Most likely there is something that just was not hooked back up.
If that is not the problem, then the next thing to do is put the old O2 sensors in and see if you have the same problem. While O2 sensors aren't the usual culprits if your car won't start, but it's best to confirm.
Answer: If it did not do this before you replaced the O2 sensors, then you must have either forgotten to plug something back in or you might have hit something. The first thing to do is re-check everything that you might had removed or disconnected to do this job. Most likely there is something that just was not hooked back up.
If that is not the problem, then the next thing to do is put the old O2 sensors in and see if you have the same problem. While O2 sensors aren't the usual culprits if your car won't start, but it's best to confirm.
Car Won't Start, No Spark
1994 Chevy Camaro V6 3.4L. It quit running while driving. I checked all fuses in car and under the hood. When you turn the key, you can hear fuel pump build up pressure like it should. When you try to start it turns over fine. I pulled one spark plug wire and had it in close to body bolt to see if I could get a spark and I did not get anything so my question is where should I start my troubleshooting?
Answer: Since your car wont't start and there is no spark, you need to first check the spark plugs and wires. It is not likely that these are the problem but it is possible. The next thing you need to check is to see if the distributor is getting power and if the coil is sending spark to the plugs.
Some of the most likely causes of this problem are the coil, ignition control module and crankshaft sensor.
Answer: Since your car wont't start and there is no spark, you need to first check the spark plugs and wires. It is not likely that these are the problem but it is possible. The next thing you need to check is to see if the distributor is getting power and if the coil is sending spark to the plugs.
Some of the most likely causes of this problem are the coil, ignition control module and crankshaft sensor.
Car Won't Start After Short Drive
My 2005 Equinox LT bgean with a simple problem. The car would start up fine in the morning and after sitting a long time but if I ran in the store or to pick up kids, my car won't start - I'd have to let it sit for a minute or two - it kinda seemed like the engine was flooded.
Well, just the other day, after an 8 hr day at work, I went to start it and nothing clicked/started no sound whatsoever. Then I tried it again, and it started up fine, no lag or strange sound. I thought it was a fluke until I went to pick up my son (5 min drive) and came back to find my car wouldn't start, no sound again. Even after trying to jump it for 5 min, the lights would come on but wouldn't start.
My husband thought it was the battery, so he took it out and tested the voltage. It was fine. He put a new battery in and it didn't start. He put the old battery back in and the car started. Thoughts?
Answer: This sounds like a frustrating problem. I know you're looking for car won't start help, but unfortunately I cannot be of much service.
Answer: This sounds like a frustrating problem. I know you're looking for car won't start help, but unfortunately I cannot be of much service.
The main problem is that there are many things that can lead to this type of problem. It could be one of your engine sensors, it could be one of several computers on your car, it could be a wiring problem, an ignition switch problem or even and anti-theft problem.
You mentioned that putting the old battery in made it start again, so you might try cleaning and tightening the battery cables. If they are clean and tight, you might try wiggling them while someone tries to start it to see if that will get it to start.
Other than that the best advice I can give you is to take it to a repair shop that you trust to diagnose it. This is something that the dealer might have to diagnose, but some really good independent repair shops could probably do it too.
You mentioned that putting the old battery in made it start again, so you might try cleaning and tightening the battery cables. If they are clean and tight, you might try wiggling them while someone tries to start it to see if that will get it to start.
Other than that the best advice I can give you is to take it to a repair shop that you trust to diagnose it. This is something that the dealer might have to diagnose, but some really good independent repair shops could probably do it too.
Car Won't Start, Starter Works, Alternator Works, Battery Works
I have a 2000 Ford Windstar. One day it just won't start. We got it jumped and it worked. Something had drained the battery. We had the starter, alternator and battery tested. All were good.
They also said there was no drain but if we left our battery connected overnight it would be dead the within a day. We just disconnected the battery at night and all seemed fine until one day we went somewhere and when we got in the van would not start.
We tried to get it jumped and it still would not start. We were told it was the starter so we replaced the starter and it turned on. The next day we went somewhere again and it wouldn't restart once again. We tried to jump it once again and it did not work. It clicked a couple of times and then just wouldn't even click anymore.
A mechanic hit the starter to get it to turn over. He told us the starter that we had just put in was bad. He tested the cable and said the power was going to the starter. We took the starter out and back to the store to get tested and were told it was working fine. We put the starter back in and it has worked for the day.
It did take a lot of cranking when we started it this morning. Any ideas what exactly could be going on?
Answer: Hi Misty. I think you'll need to find a mechanic who is great at diagnosing electrical problems.
Answer: Hi Misty. I think you'll need to find a mechanic who is great at diagnosing electrical problems.
Specifically, they need to know how to do what is called a "voltage drop" test. This is a test that can tell you exactly what is bad in any electrical circuit. Believe it or not, there are plenty of mechanics out there who do not know how to carry out this test. If you can find a repair shop that specializes in electrical systems they will probably have someone that will know how to do it.
As to your question, there are any number of things why your car won't start. I have seen starters that test just fine, but when you get them installed they don't work. They can be worn out inside and not work when they are installed, but then they can be taken off of the car, get bumped around and test just fine.
I have also seen these type of problems be caused simply by loose battery cables. It is surprising how many times I have seen major problems caused by such a simple thing.
Another thing it could be is your ignition switch. If it is bad it might not be sending the right amount of voltage to the starter in order to get it turning.
As you can see, there are many things that can cause this type of problem. If I had to guess I would say it is a starter problem, but to really find out you need to take it to a really good electrical mechanic.
As to your question, there are any number of things why your car won't start. I have seen starters that test just fine, but when you get them installed they don't work. They can be worn out inside and not work when they are installed, but then they can be taken off of the car, get bumped around and test just fine.
I have also seen these type of problems be caused simply by loose battery cables. It is surprising how many times I have seen major problems caused by such a simple thing.
Another thing it could be is your ignition switch. If it is bad it might not be sending the right amount of voltage to the starter in order to get it turning.
As you can see, there are many things that can cause this type of problem. If I had to guess I would say it is a starter problem, but to really find out you need to take it to a really good electrical mechanic.
Car Won't Start, Turn Overs Then Dies
Just got the brakes fixed on my 2001 Dodge Ram 2500 and noticed that it was hard to start and the battery indicator said batt was low (left it sitting for three weeks while out of town), so jumped it and took it to the shop for brakes.
Just got the truck back and again it seemed hard to start, so figuring it just needed to charge I was going to let it sit but IT WONT START! I tried jumping thinking the battery was still low and nothing. There is no light on the dash and when I turn the key it says 'wait to start' as always but when I go to turn it on it tries to turn over but then just dies. What could be happening?
Answer: It sounds like the jumper cables might not have had a good enough connection. My guess is that your battery is weak so it keeps losing its charge. If it sat around with a low battery for very long, then it is most likely bad.
Answer: It sounds like the jumper cables might not have had a good enough connection. My guess is that your battery is weak so it keeps losing its charge. If it sat around with a low battery for very long, then it is most likely bad.
You can have them tested at most auto parts stores for free. Be sure to have them do a load test. This test puts a load on the battery to see if it is good and is much more accurate than any other test.
You should also check your battery cables and connections. If there is any corrosion or if they are loose they can cause this very problem. You can use a mix of baking soda and water to clean them up.
You should also check your battery cables and connections. If there is any corrosion or if they are loose they can cause this very problem. You can use a mix of baking soda and water to clean them up.
Car Won't Start, Clicking Noise, Won't Turn Over
My car won't start. What does it mean when your car is making a loud fast clicking noise and the engine doesn't turn over? (1994 Mazda B4000 2WD Truck)
Answer: Thanks for submitting your question. The most likely cause of your problem is not enough voltage is getting to the starter.
There are several common causes of this condition. The first and most likely is that you have a bad battery. You can have it tested at any good auto parts store. If it is not fully charged or faulty, it might send the right amount of voltage to your starter... thus causing the clicking noise.
It could also be a starter or starter solenoid problem. If it is faulty, it can cause this type of clicking noise.If the battery tests good then you probably need a new starter.
It is also possible that you have some type of wiring problem in the ignition circuit. You could also just have loose or corroded battery cables.
Answer: Thanks for submitting your question. The most likely cause of your problem is not enough voltage is getting to the starter.
There are several common causes of this condition. The first and most likely is that you have a bad battery. You can have it tested at any good auto parts store. If it is not fully charged or faulty, it might send the right amount of voltage to your starter... thus causing the clicking noise.
It could also be a starter or starter solenoid problem. If it is faulty, it can cause this type of clicking noise.If the battery tests good then you probably need a new starter.
It is also possible that you have some type of wiring problem in the ignition circuit. You could also just have loose or corroded battery cables.
Car Won't Start on First Try
When my 2006 Cobalt LT 2.2 liter sits for over a few hrs, it will not start on the first try but it has always started the second try. This problem just started a few days ago. I can tell that the ignition is working fine but it sounds like it isn't getting gas or something.
I just replaced the fuel filter last night to see if that was the cause but then again this morning it took two times to try and start. Does anyone have any idea what this could be? I think it is a problem with something in the fuel system but am not sure why my car won't start on first attempt. Please help! Thanks, David G.
Answer: The first thing you need to do is find out whether this is a spark problem or a fuel problem.
Answer: The first thing you need to do is find out whether this is a spark problem or a fuel problem.
In order to do this you will need a fuel pressure tester and an inline spark tester. Test the fuel pressure when it won't start and test the spark when it won't start. If the fuel pressure is low then you are looking at a fuel pump, or regulator problem most likely.
If there is no spark when car won't start, then you are most likely looking at a problem with things like the ignition control module, coils, ignition switch etc.
Car Cranks But Won't Start, Smoke Exhaust
I have an 1988 Buick Century 3.8 it will crank but not start. It's getting fire and gas to the fuel rail. Smoke comes out of the air filter? HELP PLEASE.
Answer: There are several possible reasons why your car won't start. Since you are getting fuel (and I'm assuming that you are getting the right fuel pressure as well) and you are getting spark, this helps me narrow the possibilities.
Three main things are needed for your car to start: spark, fuel and compression. Timing is required as well. Since you already have spark and fuel, we should be able to safely say that the problem is likely related to compression and/or timing.
Answer: There are several possible reasons why your car won't start. Since you are getting fuel (and I'm assuming that you are getting the right fuel pressure as well) and you are getting spark, this helps me narrow the possibilities.
Three main things are needed for your car to start: spark, fuel and compression. Timing is required as well. Since you already have spark and fuel, we should be able to safely say that the problem is likely related to compression and/or timing.
The first thing you should do is check the compression of your engine. Make sure that the cylinders have the necessary compression to ignite the incoming fuel and air mixture.
Next, you need to check timing. If there is fuel and spark but the timing is not correct it will not start. One of the best ways to do this is to bring the #1 cylinder up to top dead center compression then remove the distributor cap and see if the rotor is pointing to the #1 cylinder. You can be sure it is on TDC on the compression stroke by removing a valve cover and checking to make sure the rocker arms are a little loose.
If the rotor is not pointing to the right spark plug wire, then you might have a timing belt/chain problem. Sometimes they will slip or the gears or belt will wear and cause the timing to become misadjusted.
Another easy check you can do is a vacuum check. If the vacuum is low then you might have a plugged catalytic converter or a vacuum leak.
Be sure that all of your ignition components (spark plugs, wires, cap, rotor, etc.) are in good condition.
Some of these 3.8L engines had a problem with the wiring that goes to the distributor. To check this, you can have someone wiggle these wires while you crank the engine to see if it will start. If it does then you have probably found your problem.
Next, you need to check timing. If there is fuel and spark but the timing is not correct it will not start. One of the best ways to do this is to bring the #1 cylinder up to top dead center compression then remove the distributor cap and see if the rotor is pointing to the #1 cylinder. You can be sure it is on TDC on the compression stroke by removing a valve cover and checking to make sure the rocker arms are a little loose.
If the rotor is not pointing to the right spark plug wire, then you might have a timing belt/chain problem. Sometimes they will slip or the gears or belt will wear and cause the timing to become misadjusted.
Another easy check you can do is a vacuum check. If the vacuum is low then you might have a plugged catalytic converter or a vacuum leak.
Be sure that all of your ignition components (spark plugs, wires, cap, rotor, etc.) are in good condition.
Some of these 3.8L engines had a problem with the wiring that goes to the distributor. To check this, you can have someone wiggle these wires while you crank the engine to see if it will start. If it does then you have probably found your problem.
Fuel Pump Works But Car Won't Start
My truck died on the way work. I got it to start again after work and drove it home. I got it started again to drive it closer to my home and it died again after a few seconds.
Now I can't seem to get it to start again unless I use starting fluid. Since I could run it on starting fluid, I knew I had spark. I had a new high pressure pump replaced a couple of months before. I know I am getting fuel to the high pressure pump and to the fuel pressure regulator.
I changed the fuel pressure regulator with no success. I then changed the ignition module with no effect. I am at the end of my rope here with no ride to work. Please any help you can give would be greatly appreciated. Thanks, James B. (1988 Ford F-150 4.9L 6 Cylinder)
Answer: It sounds like you are right in saying that you have good spark and probably good fuel pressure. This helps us narrow down the possible causes for your fuel system problem.
The first thing that comes to mind is that you should check your fuel pressure just to make sure it is not dropping out. This is a very easy thing to check with a fuel pressure gauge.
It sounds like the computer might not be telling the fuel injectors to turn on. Your truck's computer gets information from the crankshaft and camshaft sensors (as well as a few others) to determine when to fire the injectors and for how long.
What you need to do is get a noid light and plug it into the injector harness. Then crank your engine like you are trying to start it. If the computer is telling the injectors to come on, then the light will blink. This is one of the best ways to tell if they are working.
Answer: It sounds like you are right in saying that you have good spark and probably good fuel pressure. This helps us narrow down the possible causes for your fuel system problem.
The first thing that comes to mind is that you should check your fuel pressure just to make sure it is not dropping out. This is a very easy thing to check with a fuel pressure gauge.
It sounds like the computer might not be telling the fuel injectors to turn on. Your truck's computer gets information from the crankshaft and camshaft sensors (as well as a few others) to determine when to fire the injectors and for how long.
What you need to do is get a noid light and plug it into the injector harness. Then crank your engine like you are trying to start it. If the computer is telling the injectors to come on, then the light will blink. This is one of the best ways to tell if they are working.
You can also use a long screwdriver and put one end on the injector and the other on your ear and see if you can hear a "pulse". This is much harder because there are so many other noises that sound similar.
Once you determine whether or not the computer is turning on your injectors you will be able to further narrow it down. If the injectors are coming on then you need to look at timing, exhaust backpressure (possible plugged exhaust), etc. If they are not coming on then you need to look at crankshaft and camshaft sensors, wiring etc.
Car Won't Start, Cranks But Engine Won't Turn
I have a 2000 Ford Contour SE 4 cylinder engine. 2.0 L. I have had many problems with this car since I bought it. I had the fuel tank and pump replaced last year. If I do not put Gumout in my gas tank every time I fill up the car, the car starts to sputter while driving from 50 mph-60 mph.
Recently every once in a while the car would start and stall, but it would always fire up on the second try. Yesterday, the car started fine and I drove it for a few errands, then when I got home I turned off the car, ran inside the house and came back out and my car won't start! It cranks, but the engine will not turn.
It does have gas, but I checked the oil and the dip stick showed that it was bone dry (this annoys me because I just got the oil changed 2 months ago).
It does have gas, but I checked the oil and the dip stick showed that it was bone dry (this annoys me because I just got the oil changed 2 months ago).
I have checked all of my fuses and none of them are bad. I started to check the spark plug wires and they look fine, but when pull it off of the spark plug it has oil at the tip of it. I do not have tool to get the spark plug out, but I can tell there is oil down there. I have only checked in one terminal. What could be the potential problems?
Answer: The first thing that needs to be done is to see if you have spark and fuel pressure. You will need an inline spark tester and a fuel pressure tester for your car.
Answer: The first thing that needs to be done is to see if you have spark and fuel pressure. You will need an inline spark tester and a fuel pressure tester for your car.
Once you determine whether you are lacking spark or fuel pressure, then you can start narrowing down the possibilities.
If you don't have spark then you are looking at an ignition component. Things like the coil, ignition control module, etc. If you don't have good fuel pressure then you are looking at things like the fuel pump, fuel filter, fuel pressure regulator. Even though the fuel pump has been changed it could still be bad. Many fuel pumps even new are not reliable.
Even though the dipstick shows that there is no oil, there is probably oil in the oil pan... just not enough to show on the dipstick. While you should add oil as soon as possible, this problem will not cause it to not start. If your engine truly didn't have any oil in it then there would be a light on the instrument panel and probably an audible warning of low oil pressure.
The oil on the spark plugs is most likely caused by a bad valve cover gasket, but also shouldn't be a reason your car won't start.
Even though the dipstick shows that there is no oil, there is probably oil in the oil pan... just not enough to show on the dipstick. While you should add oil as soon as possible, this problem will not cause it to not start. If your engine truly didn't have any oil in it then there would be a light on the instrument panel and probably an audible warning of low oil pressure.
The oil on the spark plugs is most likely caused by a bad valve cover gasket, but also shouldn't be a reason your car won't start.
Car Won't Start Sometimes Unless Brake is Pressed
My car won't start sometimes when I turn the key. I have to depress the brake and she will turn over. I've never had to press the brake before. Please help. (2000 Toyota 4Runner)
Answer: All cars with an automatic transmission have a safety feature that will not let the key turn over unless the car is in park or neutral. This neutral safety switch will not send power to the starter until the gear shifter is in park or neutral.
There is also a feature that will not let the gear shifter move out of park until you put your foot on the brake. Sometimes these two things are part of one assembly. If these parts get worn it might cause the problem that you are having.
The most likely cause of your problem is this neutral safety switch that is not working correctly. I'm guessing that when you step on your brake it causes the neutral safety switch contacts to move just a little and send power to your starter like it should.
I think if you have your neutral safety switch replaced it should fix your problem of your car not starting.
Answer: All cars with an automatic transmission have a safety feature that will not let the key turn over unless the car is in park or neutral. This neutral safety switch will not send power to the starter until the gear shifter is in park or neutral.
There is also a feature that will not let the gear shifter move out of park until you put your foot on the brake. Sometimes these two things are part of one assembly. If these parts get worn it might cause the problem that you are having.
The most likely cause of your problem is this neutral safety switch that is not working correctly. I'm guessing that when you step on your brake it causes the neutral safety switch contacts to move just a little and send power to your starter like it should.
I think if you have your neutral safety switch replaced it should fix your problem of your car not starting.
Why does my car crank but not start?
Based on the problems you are describing it's a bit difficult to diagnose a specific problem without seeing the car or hearing it start. But I can suggest a few things to have checked: Fuel filter, and pump (car won't fire up if there is no fuel supply)
Alternator (not a likely culprit because the car still has power to turn over)
Starter (a possibility, but usually this will click and not turn over at all if the starter is the culprit)
Spark (there could be an issue with spark plugs)
Basic Engine Cranks But Won't Start?Reasons
To run, a gasoline internal combustion engine needs 3 things:
Air ---- Fuel ---- Spark
The air is provided by the intake system. This includes an air filter, piping, a throttle valve, an inlet manifold, and in modern vehicles also includes an air flow meter (with some exceptions, which gather the same information from other sensors) and a throttle position sensor, among other things.
The fuel is provided by the aptly named fuel system. This is made up of a fuel tank, one or more fuel pumps, one or more fuel filters, lines, a fuel rail and fuel injectors. Fuel flow to the cylinders is provided and controlled by the injectors, which in turn are controlled by the ECU, or electronic control unit, based on factors such as the air flow and temperature, engine coolant temperature, among other things.
Spark is provided by the ignition system. Depending on the car, this can be made up of a single coil and distributor, a single electronic coil or coil pack, or up to one coil per cylinder. Regardless of the coil and distribution setup, all gasoline engines must have spark plugs, which ignite the air/fuel mixture in the cylinders at the beginning of each cylinder's power stroke.
So Think; gas, spark, air.
Presuming the engine is turning over you will want to investigate the gas situation. Procure a can of starting fluid, take the air cleaner top off to expose the carburator and squirt a 3 to 5 second burst from the can of starter fluid directly into the throat of the carburator and turn the key to start the engine. If the engine fires and runs for a couple of second then you are not getting gas to the carb in the usual way, and this can happen because you are out of gas, have a plugged gas filter of which there are several, typically one in the tank, one inline under the car, one under the hood usually found on the passenger compartment wall inline with the line to the carb, and also one in the carb itself. Additionally, your fuel pump might not be working, in which case you should be able to disconnect the fuel line at some point prior to the carb, turn the engine over and gas should pump thru the line while the key is turning and if it doesn't it's probably time for a new fuel pump.
If you provide a squirt of starting fluid into the carb and it wont start..it may have been flooded, and you should note whether the inside of the carb has excess gas in it and smells obviously of gas. In these conditions you would wait for the gas to evaporate and simply try turning the engine over again. It's helpful to have a second person to turn the key while you observe what the engine is doing.
Having gone through the above and you have not had any cylinder fire under any circumstance then your engine may not be providing a spark to the plugs. Depending on the age of your engine this could be a variety of things from plugs, to plug wires, rotars, and so on. You can learn the most by pulling a spark plug and viewing the end of it. If the plug is wet it is getting gas but has not gotten the spark or not gotten the spark at the appropriate time. In which case you need to look at rotar adjustments on older cars and or plug and or plug wire replacement. If the end of the spark plug is black and has a heavy coating of black material on the end of it then it has not been firing hot enough meaning that the points of the plug itself have eroded and need to be regapped or the plug replaced. It the plug is all white material it maybe that the plug gaps have been set too close together. Not all plugs come gapped properly and may not have been gapped for your particular make and model of car so you need to check them.
Check the air intake filter, clean and replace as necessary, Also, on older engines you may have come to a point where the engine is backed up because the exhaust system has been plugged up and no air exit is available. First indications of this are low power going up hills, but can proceed to engine overheating and nonstart/non-run conditions.
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Car No Start Diagnosis:
When a car won't start there is usually one key thing that you need to know.
"is it cranking or not"?
Now, what is cranking? Cranking is referred to as the noise that you hear before an engine is started. If an engine is not cranking then you would either hear a clicking noise, or no noise at all.
So let's look at the different things that could cause an engine "NOT" to crank, and instead cause a clicking noise or no noise at all.
If you try to start your car and you don't hear anything, or all you hear is a clicking noise, it could be a few things.
A bad battery - (the job of the battery is to supply voltage to sensors, actuators, and motors in the vehicle. In some rare cases a low battery will cause an engine to crank slowly, but 90% of the time a low battery will cause your car to make a clicking noise or cause a no crank no start condition)
Dead Battery is not the reason because in case of a dead battery, the car doesn't crank.
If your car is cranking but not starting, there is a problem with the starting system which could actually be because of a variety of reasons.
Problem could be with the starter motor
There could be a problem with the relay
Get your spark plugs cleaned
Low Battery charge.
A bad starter - (the job of the starter is to take the voltage that has been supplied by the battery, through the ignition switch, through the neutral safety switch, and crank the engine over. A bad starter will cause a no crank no start condition)
A bad neutral safety switch - (the job of the neutral safety switch is to complete the circuit between the ignition switch and the starter. A bad neutral safety switch will cause a no crank no start condition)
* - A loose or bad connection to the starter
* - A loose or bad connection to the battery
* - An open fuse between the starter circuit
A bad ignition switch - (the job of the ignition switch is to take the voltage from the battery and complete the circuit from the battery to the starter, thus cranking the engine over. A bad ignition switch will cause a no crank no start condition)
Now let's look at the things that would cause an engine to crank but not start.
If you try to start your car and you hear the engine cranking (trying, but just not starting) it could be a few things.
In order for a gas engine to start once it is cranking you need three things.
Air or Compression, Fuel, and Spark. If you are missing one the engine will never start.
*No Air - or Compression (Lack of compression would cause an engine to crank but never start. Things that could cause lack of compression are:
- Timing belt or Timing chain broken and or out of time
- Internal engine damage, pistons, valve, head gasket etc.
- Clogged catalytic converter
No fuel
(Lack of fuel would cause an engine to crank but never start. Things that could cause lack of fuel are:
- Bad fuel pump
- bad fuel injector
- open fuse or relay in fuel pump circuit
- No gas, or bad gas
- plugged fuel filter, or lines
2. *No spark (Lack of spark would cause an engine to crank but never start. Things that could cause lack of spark are:
- bad spark plug
- bad ignition coil, wires, or distributor
- Bad crank sensor, cam sensor or computer. (This could prevent spark and fuel when bad)
So next time your car doesn't start ask yourself. Is it cranking or not, and then take a look at this list.
There are things an engine needs to start and run properly
1) A BATTERY with enough power to turn the engine over fast enough to start
2) A good STARTER strong enough to turn the engine over fast enough to start
3) A engine in good mechanical shape with the correct VALVE TIMING and high enough COMPRESSION to start.
4) Proper fuel air mixture delivered to engine by the CARBURETOR or FUEL INJECTION SYSTEM. No fuel, no start
5) Proper spark of high enough voltage across good SPARK PLUGS. No spark, no start .
This spark must happen at the correct time. This is called IGNITION TIMING.
This spark must happen at the correct time. This is called IGNITION TIMING.
Click on the above links for test procedures on all 5 essential car systems!
Some quick field tests for no start condition:
There are 2 stages you go through when starting a vehicle. The first part is "turning the engine over". This is done by the vehicle's starter. After the engine is spinning over, fuel is admitted to the cylinders and is ignited, and the engine starts to run under its own power. If a vehicle "turns over" but won't start, there is probably NOTHING WRONG with your starter, battery, or alternator. The old folk term for this is "It will turn over, but it won't catch!"
So if your vehicle does nothing when you turn the key to start, or it turns over slowly, or clicks, see articles on batteries and starters for diagnostic help.
If your car turns over fine, but won't "catch", read on!
(This stuff is REALLY IMPORTANT: I don't know how many times a customer has come to me and said his car doesn't start, and he suspects the starter. I'll get in the car, and the starter will spin the engine over very nicely. The starter only rotates the engine until it starts: in fact on a manual transmission car you can push start it or roll down a hill and release the clutch, and not even use the starter! )
Cars that won't start when the engine is turned over by the starter usually have either a fuel supply problem or a no spark problem. A broken timing belt or chain can also stop your car dead! It won't start again until you fix the belt or chain.
Here are some easy no start tests to do:
NO START TEST 1 (non-risky)
Note: this applies to fuel injected gasoline engines. Most all engines made after 1990 are fuel injected.
Get a friend to sit in the driver's seat. Go to the gas filler cap. Remove the cap and listen to the open gas filler pipe. Have the friend turn the ignition switch on, but don't turn the engine over ( the rrrrrr sound, like you were trying to start the engine ). You should hear a whirring sound from the gas tank for a few seconds, then it should stop. This is the electric fuel pump running. No whirring sound, no running fuel pump, no start! This means your fuel pump is either bad, or the relay powering it is bad, or the computer which runs the relay is bad, etc. There are some vehicles with electric pumps where the pump only runs when the engine is being turned over by the starter. Have your assistant turn the engine over and listen again. If there's still no "whirring" sound, there's no pump action.
See my article on FUEL PUMPS for more fuel related no start information.
NO START TEST 2 (COULD BE DEADLY if you have a pacemaker, otherwise unpleasant if you get a shock: careful now!!!)
Remove a spark plug wire. Insert a screwdriver or other metal object in the plug wire end. Hold this wire about 1/8 to 1/4 inch from a metal part of the engine. Have the friend turn the motor over. (making the rrrrr sound like you were trying to start the engine). There should be a nice blue spark jumping off the screwdriver to the engine metal part (pick a part: any part).
DON'T LET THE SPARK GET NEAR THE BATTERY: IT WILL EXPLODE!!!!!!!!!!!!!!!!!!
CAREFUL!!!! IT CAN BITE!!!!!!!!!!!!
No spark can be from a bad coil, rotor, distributor cap , electronic igniton module, pickup coil assy., or wiring defect.
DON'T LET THE SPARK GET NEAR THE BATTERY: IT WILL EXPLODE!!!!!!!!!!!!!!!!!!
CAREFUL!!!! IT CAN BITE!!!!!!!!!!!!
No spark can be from a bad coil, rotor, distributor cap , electronic igniton module, pickup coil assy., or wiring defect.
TIMING BELT NO START CHECK: MOST CARS
Remove oil filler cap. Should be able to see the camshaft. Have a friend crank the engine: No cam turning, timing belt gone for sure! If you can't see the cam, remove the distributor cap. With only a few exceptions, the distributor is driven off the camshaft. Distributordoesn't turn with motor, probably the belt is bad.
A NOTE ON BAD TIMING BELTS
When the timing belt goes bad the engine will have LOW COMPRESSION: Often it will have NO COMPRESSION! No compression, no start!
Easy way to determine low compression
An engine with LOW COMPRESSION will spin over really fast compared to an engine with good compression. As you try to start it the engine will sound differently: higher pitched, spinning a lot faster than normal.
WHAT CAUSES LOW COMPRESSION
The most common causes of low compression:
BAD VALVE TIMING, usually from a bad timing belt or chain
A BLOWN HEAD GASKET, usually from overheating. Engines with aluminum heads are especially "delicate". Get one hot and it will blow a head gasket QUICKLY!
If you do everything right on your engine it still won't last forever. Eventually the piston rings or valves will wear out and it just won't have enough compression to start anymore.
If you've got the right genes and live right, you might just live to be over 100 years old. Eventually, though, you'll die: of heart failure. The old pump just goes on for so long.
If you take care of your car and it's a good make of car you very likely will go 200,000 miles or more. Some go 300,000. One day, though, it won't start anymore: dead from low compression.
AN OLDTIME TRICK
On older motors you can sometimes squirt some oil in the cylinders and it will bring the compression up enough to start. This used to happen to the old "Detroit Iron" V-8's back in the 60's and 70's when someone would overheat them. Those motors could overheat enough to burn all the oil off the piston rings and not blow a head gasket. Newer motors blow a head gasket LONG BEFORE they get hot enough to burn the oil off the rings, so unless you've got a classic with low compression this probably won't work.
NO FUEL NO START TESTS
If you have spark and compression but the car still won't start you probably have a fuel supply problem.If in the first no start test you did above you could hear the fuel pump "whirring" then you still could have a FUEL INJECTION problem.
A QUICK FUEL TEST FOR ALL GAS ENGINES
Get a can of engine starting fluid. Any parts store has it. Spray some in to the intake manifold (removing a vacuum line is a good way) CAREFUL!!!! THAT STUFF IS HIGHLY FLAMMABLE!!! DON'T PUDDLE THAT STUFF ON THE MOTOR!!!
If the motor "tries to start" then you have a fuel supply problem.
See articles on FUEL INJECTION, FUEL PUMPS, and COMPUTERS for diagnostics and more information on fuel no start problems.
See articles on FUEL INJECTION, FUEL PUMPS, and COMPUTERS for diagnostics and more information on fuel no start problems.
Here's a good article on Toyota ignition and coil tests: Here's a good "no start" diagnostic flowchart
When you turn the ignition key to start your car, or press the START button, voltage from the battery flows through the ignition switch to the Park/Neutral safety switch and/or brake pedal or clutch pedal safety switch (you have to push the pedal down before the circuit will complete) to the starter relay or solenoid. When the relay or solenoid is energized by voltage from the ignition switch circuit, it closes a contact that routes more power from the battery directly to the starter to crank the engine. The starter motor spins, pushes the starter drive gear to engage the flywheel and cranks the engine.
If the engine fails to crank, there is a fault in one of the components in the battery/ignition/starter circuit.
COMMON CAUSES OF NO-CRANK NO-START
Low battery (Check battery voltage, recharge if low, or jump start with another vehicle or battery charger).
Loose or corroded battery cables (Inspect, clean and tighten BOTH ends of BOTH battery cables).
Bad starter relay wiring connections or ground connection (Inspect, clean, tighten wiring connections).
Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay).
Bad starter (Jump battery voltage direct to starter to see if it spins, or remove starter and have it bench tested at auto parts store).
Damaged starter drive or teeth on flywheel (Remove starter and inspect drive gear and flywheel teeth, replace damaged parts if necessary).
Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).
Open P/N safety switch, or open Brake Pedal Safety Switch (automatic transmission) or open Clutch Pedal Switch (manual transmission). Bypass switch with jumper wire to see if engine cranks, or use test light or voltmeter to check for voltage passing through switch when ignition is turned to start.
Engine seized due to bearing failure or internal damage (Use socket and long handle to see if engine can be turned by hand, if not engine is locked up).
Engine hydrolocked due to coolant leak from leaky head gasket (Use socket and wrench to see if engine rotates, remove spark plugs and see if coolant comes out or engine can not be cranked with plugs out).
Loose or corroded battery cables (Inspect, clean and tighten BOTH ends of BOTH battery cables).
Bad starter relay wiring connections or ground connection (Inspect, clean, tighten wiring connections).
Bad starter relay/solenoid (Check for voltage at relay, if relay has voltage but there is no "click" when key is turned to start, replace relay).
Bad starter (Jump battery voltage direct to starter to see if it spins, or remove starter and have it bench tested at auto parts store).
Damaged starter drive or teeth on flywheel (Remove starter and inspect drive gear and flywheel teeth, replace damaged parts if necessary).
Bad ignition switch (Check to see if voltage reaches starter relay/solenoid when turn to start. If not, check for open P/N switch and brake or clutch pedal switch. Replace ignition switch if defective).
Open P/N safety switch, or open Brake Pedal Safety Switch (automatic transmission) or open Clutch Pedal Switch (manual transmission). Bypass switch with jumper wire to see if engine cranks, or use test light or voltmeter to check for voltage passing through switch when ignition is turned to start.
Engine seized due to bearing failure or internal damage (Use socket and long handle to see if engine can be turned by hand, if not engine is locked up).
Engine hydrolocked due to coolant leak from leaky head gasket (Use socket and wrench to see if engine rotates, remove spark plugs and see if coolant comes out or engine can not be cranked with plugs out).
ENGINE CRANKS OKAY BUT WON'T START
If the engine cranks over normally when you attempt to start you car, but the engine does not start, the problem may be NO FUEL, NO SPARK or NO COMPRESSION. The engine needs adequate fuel pressure, a properly timed spark and normal compression to start.
TIP: To find why the engine won't start, remove the air inlet tube from the throttle body, push the throttle open and spray a small amount of aerosol starting fluid into the engine. Crank the engine. IF it has spark and compression but NO FUEL, it will start and run a few seconds before dying. If it does NOT start, it probably has NO SPARK.
TIP: Another method to check for spark is to pull a spark plug wire off of a spark plug (if it has plug wires, coil-on-plug ignitions do not) and place the open end of the plug wire near a metal surface on the engine. Have a helper crank the engine while you watch for a spark. DO NOT hold the wire while doing this as it can shock you. If you see a spark, the problem is not spark, but most likely NO FUEL or NO COMPRESSION. If you do not see a spark, the problem is in the IGNITION CIRCUIT.
TIP: Proper fuel pressure is critical for fuel injected engines to start and run. You should hear the fuel pump inside the fuel tank buzz for a couple of seconds when the ignition is turned on (no buzz means the pump is not running and the engine is not getting fuel). You can smell the tailpipe for gasoline vapors after cranking the engine. If you smell gas, the problem is likely not fuel but NO SPARK. You can also remove the plastic cap and press the schraeder valve test fitting on the fuel rail to see if there is any fuel pressure to the engine (not a very accurate test because fuel pressure must be at a certain level for the engine to start, for that you need a gauge). Even so, no fuel at the fuel rail would tell you fuel is not getting to the engine.
FUEL RELATED CAUSES OF A NO START
If your Anti-Theft light is flashing, the anti-theft system is disabling the fuel pump to prevent the engine from starting. The problem could be a defective chip in a smart key, or a dead battery in a smart key or keyless entry fob, or a fault in the Anti-Theft system itself.
Bad fuel pump (Pump should run for a few seconds when ignition key is turned to start, no buzz means no fuel delivery to the engine).
Bad fuel pump relay (Relay is energized by PCM to route power to fuel pump when ignition is on).
Bad inertia fuel shut-off safety switch (Shuts off fuel in an accident, may have been tripped by a severe jolt, press button to reset).
Open in wiring anywhere in fuel pump wiring circuit (power or ground). Problem may be at wiring connector on top of fuel tank (hard to reach!).
No gas in fuel tank (Check the fuel gauge, and keep in mind the gauge may not be reading accurately).
Bad gas (Contaminated with water or too much alcohol or diesel fuel). If you just filled up with gas and now your car won't start, suspect bad gas.
Plugged Fuel Filter (When was the filter last changed?). Replace the filter. If plugged with rust,k fuel tank may also need to be cleaned or replaced.
Plugged or Pinched Fuel Line (Inspect fuel lines under vehicle for damage).
Leaky Fuel Pressure Regulator (Controls fuel pressure to injectors, which is critical for starting and proper air/fuel mixture).
No power to Fuel Injectors (Due to faulty fuel injector relay, blown fuse, no input signal to PCM from crank position sensor or cam position sensor, or bad PCM driver circuit). Injectors should usually have power when key is on. PCM grounds other side of injector circuit to pulse the injectors.
Major vacuum leak (An open EGR valve, disconnected vacuum hose, PCV valve, etc, can create a large vacuum leak and allow too much air to be sucked into the engine. This will make the air/fuel mixture too lean and make the engine hard to start. Engine will usually idle rough if it does start.
Bad fuel pump relay (Relay is energized by PCM to route power to fuel pump when ignition is on).
Bad inertia fuel shut-off safety switch (Shuts off fuel in an accident, may have been tripped by a severe jolt, press button to reset).
Open in wiring anywhere in fuel pump wiring circuit (power or ground). Problem may be at wiring connector on top of fuel tank (hard to reach!).
No gas in fuel tank (Check the fuel gauge, and keep in mind the gauge may not be reading accurately).
Bad gas (Contaminated with water or too much alcohol or diesel fuel). If you just filled up with gas and now your car won't start, suspect bad gas.
Plugged Fuel Filter (When was the filter last changed?). Replace the filter. If plugged with rust,k fuel tank may also need to be cleaned or replaced.
Plugged or Pinched Fuel Line (Inspect fuel lines under vehicle for damage).
Leaky Fuel Pressure Regulator (Controls fuel pressure to injectors, which is critical for starting and proper air/fuel mixture).
No power to Fuel Injectors (Due to faulty fuel injector relay, blown fuse, no input signal to PCM from crank position sensor or cam position sensor, or bad PCM driver circuit). Injectors should usually have power when key is on. PCM grounds other side of injector circuit to pulse the injectors.
Major vacuum leak (An open EGR valve, disconnected vacuum hose, PCV valve, etc, can create a large vacuum leak and allow too much air to be sucked into the engine. This will make the air/fuel mixture too lean and make the engine hard to start. Engine will usually idle rough if it does start.
IGNITION RELATED CAUSES OF A NO START
Bad crankshaft position sensor or distributor pickup (Sends pulse signal to ignition module and/or PCM that is necessary to trigger the ignition coil(s)).
Bad ignition module (controls firing of ignition coil(s), may have an intermittent open in circuitry that causes loss of spark, hard starting or sudden stalling, usually when hot)
Bad ignition coil(s). Ignition coil creates high voltage to fire the spark plugs. On engines with a distributor, a bad coil will prevent spark at all the spark plugs. On engines with a distributorless ignition system or coil-on-plug ignition, a bad coil will only affect one or two cylinders depending on the application. This may make the engine hard to start, but it will run on the remaining cylinders that are firing.
Cracks or carbon tracks inside distributor cap or on rotor (allows spark to short to ground before it reaches the spark plugs).
Bad spark plug wires (if wet, cracked, burned or internal resistance exceeds specifications, can interfere with good spark and make engine hard to start).
Fouled spark plugs (if the electrodes are contaminated with deposits, spark may short to ground before jumping gap causing misfires. Can make engine hard to start and run poorly. If plugs are wet when removed, it means they are not firing or engine is flooded).
Bad ignition module (controls firing of ignition coil(s), may have an intermittent open in circuitry that causes loss of spark, hard starting or sudden stalling, usually when hot)
Bad ignition coil(s). Ignition coil creates high voltage to fire the spark plugs. On engines with a distributor, a bad coil will prevent spark at all the spark plugs. On engines with a distributorless ignition system or coil-on-plug ignition, a bad coil will only affect one or two cylinders depending on the application. This may make the engine hard to start, but it will run on the remaining cylinders that are firing.
Cracks or carbon tracks inside distributor cap or on rotor (allows spark to short to ground before it reaches the spark plugs).
Bad spark plug wires (if wet, cracked, burned or internal resistance exceeds specifications, can interfere with good spark and make engine hard to start).
Fouled spark plugs (if the electrodes are contaminated with deposits, spark may short to ground before jumping gap causing misfires. Can make engine hard to start and run poorly. If plugs are wet when removed, it means they are not firing or engine is flooded).
COMMON CAUSES OF NO COMPRESSION
Broken timing belt or chain (Belt failure will prevent the valves from opening. The engine will NOT run if the belt has broken, and it may have bent valves or other damage as a result of the belt breaking).
Broken camshaft (This can happen on an overhead cam engine if the engine has overheated, warped the head and seized the camshaft).
Plugged catalytic converter (Creates a restriction that causes exhaust backpressure to back up. Engine may start but usually dies within a minute or two).
Broken camshaft (This can happen on an overhead cam engine if the engine has overheated, warped the head and seized the camshaft).
Plugged catalytic converter (Creates a restriction that causes exhaust backpressure to back up. Engine may start but usually dies within a minute or two).
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