What to do if your CAR WON'T START

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 my 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!!!)

TIMING BELT NO START CHECK: MOST CARS

A NOTE ON BAD TIMING BELTS

Easy way to determine low compression

WHAT CAUSES LOW COMPRESSION

The most common causes of low compression:

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

NO FUEL NO START TESTS

A QUICK FUEL TEST FOR ALL GAS ENGINES

If the motor "tries to start" then you have a fuel supply problem.
See my 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