heres the deal i have a 89 gta with a rebuilt 350 that i just fired up a week ago my problem is that i can start it but it will not idle and it will die without holding my foot on the gas i am getting spark and the timing is not set yet but it is not too far off. my iac and tps are all within reasonable range. i beleive i am not getting fuel, when i turn the ignition on sometimes the pump runs for 2 sec and holds pressure (45-50) then after that it drops to 0 and sometimes the pump will not turn on when i turn the ignition. Also when i crank the engine it will have pressure but then when i stop cranking it will drop to zero. the guy told me that he had replaced the fuel filter recently i checked the fuse block and its not a fuse and i have tried bypassing it through the aldl and it does not work the only way i can get the pump to work is when i bypass the relay. is there any other fuses or relays i am missing? i only had the car for about a month before i rebuilt the motor and when i tore it down i noticed that the guy before me had put in aftermarket oil press gauge and hooked it to the back of the block and moved the stock sensor some where that i do not remeber now and i do not have that hooked up my question is without that hooked up will it tell the ecm there is no oil pressure and then shut the fuel pump off? if so how come it ran before? is there any other places i can hookup the oil sensor since it is so crowded in the back

any and all help will be appreciated

thanks in advance
brendon

 

The oil pressure switch powers the pump in case of a failure in the fuel pump relay circuit. It doesn't provide any input to the ECM directly.

The ECM will turn the pump on through the fuel pump relay for 2 seconds after turning the key on for priming, and whenever it sees reference pulses coming from the distributor telling it that the engine is turning. If that's not happening, you have a problem.

 

If you bypass the relay and leave the fuel pump running continuous does the engine run?
If not, it's not the fuel pump's fault.
If it does, there is a fuse in the fuel pump circuit off all by itself between the battery and the cruise control unit. Check it for corrosion.
Here is another place to put the oil pressure sender. You'll have to use some fittings: