By February 14, 20063 Comments Read More →

Car Won’t Start? What Causes Your Car Not To Start?

Reader Question: My car won’t start, what do I do now?

Hi Liz
I hear this question everyday, and it sounds like it should have a simple answer. Unfortunately when asked that way it is all but simple. Okay so what happens when your car won’t start?

A typical gasoline engine needs three main ingredients to operate:

1) fuel (there has to be something to burn)
2) a spark to ignite the fuel
3) some way for the fuel to meet the spark and ignite a fire — this is called “compression”. Compressing gasoline in a confined cylinder inside the engine, then introducing a spark from a spark plug will produce a small explosion.
This explosion process is what generates horsepower, and makes your car go.

So before you call the mechanic and tell him your car won’t start, ask yourself this question FIRST, “What is missing in the equation (fuel, spark, compression)?” You went out to your car today, and the car won’t start… how did it not start? Suppose the engine won’t turn over. When I say the engine won’t turn over, I mean when you turn the key the engine goes…silent..(NOTHING is happening). The radio and the headlights and dashlights may still be functioning properly.

What causes the engine to turn over? The battery and the starter are the two most important elements. If the headlights are on and are good and bright, then we could probably assume the battery is strong and doing its job.

The starter motor takes electricity from the battery and turns the engine over to start the piston explosion process I described earlier. So in this case there is probably a problem with the starter, or something is hampering the electricity from the battery to the engine or starter (maybe burned or damaged wiring or a bad ground connection…something that will probably require a mechanic to correct).

The other type of “no start” occurs when the engine turns over quickly (the engine is making noise….RRRR..RRRR…RRR…RRRRR…RRRRR) like it is trying to start but will not start. So the battery and the starter are propably doing their jobs, but we are lacking one of the main exploding ingredients. Is there fuel? Look at the gas gauge first (we still get cars towed in to the shop and the “repair” is adding gas to the fuel tank!)

So, do you have compression?

Does the engine sound like it is turning over fully, or does the engine sound like it is turning over too fast or too slow? Does the engine sound like it normally does when you turn the key? A broken timing belt or timing chain will cause the engine to turn over very easily and very fast because the compression process is not taking place because there is NO compression going on inside the engine.

Is there spark? This is not as easy to determine as it sounds, and can require some tools and experience to test. Now you probably don’t care to “do it yourself” from here on out, but at least you have ruled out the battery, the starter, and a lack of fuel in the tank. This little bit of effort on your part saves the mechanic a lot of time trying to guess what happened and why, and you might actually find the problem yourself.

Is the gear select in PARK? Don’t laugh this happens. I have been to many emergency roadside assist calls only to find out the car is still in DRIVE or REVERSE. The engine will only start in park and neutral. Do you have an anti-theft device or some kind of kill switch, and is it working properly? If it is a stick shift, do you have the clutch pedal depressed all the way down on the floorboard? Are the front tires up against the curb?

It can be difficult to turn the key if the front tires are in a bind on a curb or a curb stop, or if the car has rolled back a bit after it was placed in PARK. If this has happened, you can turn the steering wheel real hard to the right, or try to physically move or rock the car forward to release the key.

If after this you are still having trouble, then it is time to call the tow truck. When you call the shop to inform them your car is on its way into their shop, you should be specific in the nature of the “no start” you’ve experienced. Saving your mechanic diagnostic time trying to troubleshoot the problem will save you money.

Austin Davis

3 Comments on "Car Won’t Start? What Causes Your Car Not To Start?"

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  1. Tom says:

    Outstanding quest there. What occurred after?
    Good luck!

  2. charles williams says:

    I’m haveing a problem with my 98 grand marquis not starting. It does turn over but it won’t fire. I have spark and fuel I don’t know how to rule out compression. Is there anything else that could cause this? I’m lost now.

    • By Austin Davis says:

      I would be more concerned with spark control and spark timing and fuel pressure. I would use a manual fuel pressure gauge to hook up to the engine to see if the pump is pumping enough fuel to start the engine. You can sometimes bang on the bottom of the fuel tank with your fist or block of wood AS someone cranks the engine over. If it starts or tries to start you probably have a weak fuel pump. Do that first.

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