91greenbird

iTrader: (4)

Well i started my car today since i do it weekly to keep everything moving. When i started it, it fires right up pressure gets up to 5 and runs good then when its running after a minute the psi goes to 0 then stalls about 30 seconds later ill turn the key on the pump comes on pressure goes back to 5 and it fires right up. What can cause the pressure to suddenly die to 0? The fuel gauge doesnt work but i dont think this is due to no gas since it well restart.

Apeiron

Your fuel pump is shutting off.

91greenbird

iTrader: (4)

but why? How can i wire it to stay running with the key on?

five7kid

iTrader: (14)

The stock EFI fuel pumps had two means of powering the pump - a timed relay that is turned on when the ignition is turned on; and a circuit that went through the oil pressure sender, powered through the ECM, typically.

What did you do when you converted to carb? You need to get power to that 2nd circuit, it sounds like.

91greenbird

iTrader: (4)

the computer is still in and the oil pressure switch is plugged in. How can I wire it to run all the time with the key on? Im going to try to get some gas in it could be out.

tompumped

iTrader: (3)

I just installed a holley oil pressure switch. If your using one of these maybe there's a problem with the wiring. Shouldn't be too hard to fix.

Thank you five seven, I never thought about being upside down in the car with the electric fuel pump running. I'm stupid sometimes, I thought it was just to save your motor. You might've indirectly saved my life, I appreciate it sir.
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I had mine directly connected to a switched power source in the fuse panel. I'm pretty sure on my '88 it was a tan wire with a white stripe. You can find wiring diagrams somewhere to let you know.

91greenbird

iTrader: (4)

nope everything is stock the only things that are unhooked is tps, maf, injectors, cts, iat. It did this to me when i had it at my work working on it. Then i would restart it and everything would be fine and went to the gas station put a few gallons in it i played with the timing beating the hell out of it to make sure there was no pinging and it would never cut off. Ill try to put some gas in it to see if it is low or out then if not ill have to find a way to wire it to run always with the key on instead of a few seconds.

bluechevy194

i had this same problem with my car, worked fine, then one day started doing this, never could figure it out though, so i just got rid of all the stock fuel system wiring and wired the fuel pump straight to the ignition switch, like older carbed cars. i just used a fuel pump relay kit off of summit, reall simple to do.

91greenbird

iTrader: (4)

So you can just by one of those and delete the factory relay?

Apeiron

What about the distributor, did you replace it with a non-CCC one?

91greenbird

iTrader: (4)

lol yes im not a dumbass or maybe i am put 5 gallons of gas in it today and it ran fine for 30 mins straight then i cut it off. Guess i need to fix that gas gauge.

Auggie

Just use the in-tank fuel pump part of this wiring dia. See in-tank fuel pump and carbs post.

Auggie

Apeiron

If you replaced the distributor, then the ECM isn't getting reference pulses anymore to know that the engine has started, so it won't turn on the fuel pump after the initial 2 second prime. The oil pressure switch would normally power the pump as the backup to the fuel pump relay, but it sounds like its failing.