I get tons of e-mails each week that ask this very simple question. Unfortunately when asked that way it is all but simple.
Okay so what happens when your car won’t start? A gasoline engine needs three key 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 fuel 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.
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? 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…blank..(nothing is happening). The radio and the lights may still be functioning fine.
What are the things that cause the engine to turn over?
The battery and the starter are the two most important. If the headlights are on and are bright, then we could probably assume the battery is up to snuff and doing its job.
The starter 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).
The other type of “no start” occurs when the engine turns over like it is trying to start but will not start.
So the battery and the starter are doing their jobs, but we are lacking one of the main exploding ingredients. Is there fuel? Look at the gauge first (we still get cars towed in to the shop and the no start correction is adding gas to the tank!)
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? 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.
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 car in PARK? I have been to many roadside assists only to find out the car is still in DRIVE. The engine will only start in park and neutral. Do you have an anti-theft device, and is it working properly?
If it is a stick shift, do you have the clutch pedal depressed? Are the front tires up against the curb? Sometimes it is very hard to turn the key if the front tires are in a bind on a curb, or if the car has rolled back a bit after it was placed in PARK. If this is the case, 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 you still have trouble 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 time should save you money.
Category: Won't Start Problems