Pontiac Repair: 1991 Pontiac Grand Prix, crank shaft position sensor, flood mode

Question
I have a 1991 Pontiac Grand Prix with a 3.4 liter DOHC Engin.It was running fine and I shut it off. It never started again. The fuel injectors are not working. What tells the fuel injectors when to spray fuel into each cylinder? None of them are working. They have power and 45 psi at the fuel rail when key is on.

Answer
Hey Jim:

Doe the engine have spark? If if doesn't have spark either then you have an issue with a bad ignition module/power or gound to the module or a bad crank shaft position sensor. The ignition module receives the signal from the crank sensor and then it produces the signal to run the 3 ignition coils. The module also sends an rpm signal to the engine computer to then run the injectors. If it has spark but no injector pulse you could have a computer issue or a bad power/ground feed to the engine computer. You could also have a bad sesnor such as a throttle position sesnor taht is bad and sending a bad signal back to the computer telling it the throttle is wide open and then the computer goes into what is called clear flood mode and it will not run the injectors. Unplug the throttle sensor and see if it starts... Just a few places to try first. Good luck :}