Jeff's DIY

Advice on doing your own diagnosis and repair

Advice from the book Can I Do It Myself?

Engine Starts but then Dies Within a Few Seconds

If the car has a security light that is flashing while you try to start the car, the security system is the likely reason for the car dying. Some models are designed to allow the engine to start even when the computer does not get a "good key" signal, but then the computer shuts off the fuel injectors to discourage theft of the vehicle. If this is your problem, focus your research on the specifics of your car's anti-theft system. If your security light is not blinking or staying on after the bulb test, please continue reading.

This issue requires a lot of careful troubleshooting. You really need a fuel pressure gage to start.

To check for fuel,

If all of that is good, you have fuel. If not, the problem is with the fuel pump, pump relay, wiring, or fuel pressure regulator. If the fuel pump is not coming on at all, you have an electrical issue. If it is coming on, and your regulator is on the fuel rail; you can test the regulator by plugging off the return line and rechecking the fuel pressure. If the pressure increases to normal only with the return line blocked, replace the regulator. If your regulator is integrated to the fuel pump or the pressure does not increase when the return path is blocked, replace the fuel pump.

If you are getting good fuel pressure and your injectors are firing, next look at sparks.

Now the only thing left is the air. Will the engine keep running if you press on the accelerator? If yes, the problem may be with the idle air control valve. Review the book section above on idle air control valve to troubleshoot that component. If all of these things are working correctly, the problem is very difficult to find, so it may be time to hire a professional mechanic. If you don't have a fuel pressure gage, you can run the other tests first or borrow a gage from Autozone.

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