1989 Buick Regal with the 3.1L V6 engine. Car runs fine for 10 minutes. If you shut it off it won’t restart but it will turn over. It has spark to all six spark plugs it has gas pressure of 45psi. Changed the ECM and ignition control module (ICM). If I wait for the engine to cool off it will start again. Idle position sensor and throttle position sensor (TPS) both work. Additional question: can the anti knock sensor cause this or possible grounding of hot lines wires to the injectors located under the intake plenum? Thanks for any help.
Answer: If the ignition system has spark then there was no need to change the ignition module so i do not know why you did that repair. The Idle and throttle position sensors will not cause a no start problem on your Buick.
It sounds like you are loosing fuel injector pulse signal. This is usually an ECM problem, since it controls the ground side. You need to check for power to the injectors with a test light. Each injector will have 12 volts at one wire and the other wire is ground that the computer controls. You can test the circuit also with what is called a noid light. It plugs into each fuel injector connector and will flash as the ECM sends the pulse signal. Most likely you have 1 or even several bad fuel injectors. This causes the ECM to not fire all of them.
You would need to remove the upper plenum and use a multi meter to check the ohms of resistance on each fuel injector individually. They should be about 12.5 ohms. Any less will cause your no start on hot engine problem.
This is a fairly common problem on that engine in your Buick. When one injector goes bad electrically it affects the whole circuit of the other 2 on that side of the engine. That will shut down the trigger circuit inside the computer. You could also have 1 bad on each side so be sure to test all of them and not just say you found it when the first one you test fails.
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