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How to diagnose a no-start problem:

Does the engine crank over when you turn the key to start? If the answer is no then you are actually talking about a no-crank problem, here are some checks to make for that situation:

1) First of all make sure your car is in park. Your vehicle won't start unless it is in park or neutral due to what is called a neutral safety switch. This switch keeps you from starting in gear.

2) Does the dome light come on inside the car and or do your headlights work? If not then you have a battery problem. If possible check for 12 volts at the battery then try charging it or jumping it with another vehicle using jumper cables.

3) If the headlights do work and you still have a no-crank problem then turn the headlights on and turn the key to start position and see if the headlights dim. If the lights don't dim then you have a solenoid, wiring, or relay problem. Check for 12 volts and a good ground at each one of these components to narrow down the problem. If the headlights do dim you most likely have a weak battery and possibly a starter or solenoid problem as they are trying to work.

Since we are actually talking about a no-start problem we will assume the engine cranks but won't run. Here are some tips to diagnose this situation:

1) Look at your gas gauge. Even though it's obvious we need gas in our tank we sometimes forget and let it run out. Check to see how full the tank is. If you are unsure and think maybe the gauge is off, try adding some gas to the tank from a gas can and then see if it will start. This will save you a lot of time and is easy to do if your gauge is not reading correctly.

2) Check for fuel at the engine. You could've done this first but it's very easy to check the gas gauge and we want to take the easiest steps possible first. Since most vehicles don't have carburetors anymore we have to check pressure, if you have a fuel pressure tester that you can screw onto the fuel rail, that is the best way to go. If you don't then you can cautiously remove the little cap that covers the test port and use a small screwdriver to push in on the valve to see if gas is present. This won't tell you pressure but will give you and indication that gas may not be the problem.

3) Check for spark. Many newer cars have the coil over plug ignition system and this may not be feasible, but if you can get to the spark plug wire and remove it, you should be able to do this check. Take a small screwdriver (a known good spark plug works even better) and insert it in the spark plug cable and then lay it close to a ground. Have someone try to start the car and watch to see if you get an ignition spark that jumps to the ground. If you do then you have eliminated the wire, coil and ignition system from being the problem.

4) If you don't get a spark at the end of the cable then go to the coil cable and check for spark there. If you get spark at the coil then you may have a distributor cap problem if applicable to your car. If you have no spark at the coil then you may have a crankshaft sensor or other computerized problem. You will most likely have to call the repair shop and have them come out to look at it or have it towed.

For an engine to start it requires fuel, spark and timing. Without one of those three things the engine will not fire and run. Always check the simplest things first and try to eliminate several items with one check such as checking at the spark plug wire cable before the coil. A no-start problem is a no-fun problem.

Good luck and stay safe!

Learn more about this author, Mike Webb.
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