5 psi to 0 psi
#1
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Car: 2012 Ram express
Engine: 5.7 hemi
Transmission: auto
Axle/Gears: 3.55
5 psi to 0 psi
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.
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
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.
What did you do when you converted to carb? You need to get power to that 2nd circuit, it sounds like.
#5
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Car: 2012 Ram express
Engine: 5.7 hemi
Transmission: auto
Axle/Gears: 3.55
Re: 5 psi to 0 psi
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.
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Car: 88 firebird
Engine: 355
Transmission: t-5
Axle/Gears: 9 bolt 3.91
Re: 5 psi to 0 psi
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.
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.
Last edited by tompumped; 04-29-2007 at 11:16 AM. Reason: Automerged Doublepost
#7
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Car: 2012 Ram express
Engine: 5.7 hemi
Transmission: auto
Axle/Gears: 3.55
Re: 5 psi to 0 psi
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.
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Car: 92 c1500
Engine: 355ci
Transmission: 700R-4
Re: 5 psi to 0 psi
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.
#9
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Car: 2012 Ram express
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Re: 5 psi to 0 psi
So you can just by one of those and delete the factory relay?
Last edited by 91greenbird; 04-30-2007 at 07:25 AM.
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Car: 1984 Z28 Camaro
Engine: H.O. 355 NOS
Transmission: 700R4
Re: 5 psi to 0 psi
Just use the in-tank fuel pump part of this wiring dia. See in-tank fuel pump and carbs post.
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Last edited by Auggie; 04-30-2007 at 04:35 PM.
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Car: 1984 Z28 Hardtop
Engine: 383 Carb
Transmission: 4L60
Axle/Gears: 3.54 Dana 44
Re: 5 psi to 0 psi
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.
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