How to diagnose a car that won't start

We've all experienced the frustration that comes when we get in our car, turn the key, and realize the car won't start. Before this happens again to you and before you turn to a mechanic who may charge more to diagnose the problem, read on and you will save time, money and your sanity. Plus you'll impress your friends who think you are clueless about cars.

You don't need to know anything about cars to diagnosis the most common causes of no-starts; just your ears. Thats right, just listen in and you can diagnose most of these causes; no special training or equipment required. For explanation purposes I've set up the remainder of this article into sections; each section is headed by the likely problem parts and followed by the noises/sounds you should listen for to determine if that is in fact the problem part. For all of these problems, you'll need to listen carefully when you turn the ignition.

Battery/Alternator-
If you turn the key and hear complete silence, your problem is most likely the battery or alternator. This means you are hearing no sounds at all, not even a sound suggesting an attempt of a start up. You can confirm one of these two parts as the problem by testing any of your electrical components in the car while the ignition is turned on such as radio, lights, windows, etc. If none work, then you've found your problem as the other problem parts wouldn't cause your electrical system to fail save for a short.

Starter-
If when you turn the key you hear what sounds like a grating/grinding sound, then this part is most likely the problem. The starter is what creates the initial electrical spark to get the whole system going. Try not to try more then 2 or 3 times if you hear a grinding sound as you can cause more damage.

Fuel Injectors/Spark Plugs-
You may have failing injectors or blocked up injectors if your car starts then sputters out, although a sputtering engine could also be due to low oil or a number of engine problems. These injectors carry the fuel to the engine where the fuel meets the sparks off of the spark plugs.

Fuel Pump-
Upon turning the ignition on, if you hear a noise from the rear of your car that sounds like any of the following: pressurized air gun, sucking, hissing, or a brief moving parts like sound followed by silence then your problem is most likely the fuel pump. The fuel pump is what takes the gas from your tank and pumps it through to your fuel injectors into your engine. A failed fuel pump can be due to the pump motor dying, low fuel levels, clog in the pump, or just an aged fuel pump.

Fuses-
A blown fuse can cause a no-start problem if the fuse that is blown is for one of the electrical components in the above list. You can use sight to check this problem by locating your fuse box and checking for fuses that are blackened or discolored.

While there are many things that can go wrong in the complex workings of a car, the above parts are the most common culprits when your car just won't start. By being able to diagnosis which of the above parts is most likely the cause you can avoid diagnosis fees and extra hourly labor from a mechanic by telling your mechanic what you believe the problem is. Some good mechanics will even let a smart customer (one that can diagnosis their own car problem) go out and purchase the trouble part and will only proceed to charge the customer labor and not for parts. Money saving and looking smart to your mechanic aside, you'll impress your friends, feel good about your knowledge, and be able to say you know something about cars.