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Old 04-07-2011   #1
tkrburnout
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Location: denver co & deming nm
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fuel pressure issues??

Well I'll start off by saying that I did a swap with the holley stealth ram intake manifold, camed and put afr heads on it, using 30lb injectors. I have the adjustable fuel pressure regulator too. I've hooked up fuel pressure gauge and saw I'm only getting 25psi of fuel pressure.
I'm guessing fuel pump, but idk much about the specs of the pump, I current ramped the fuel pump and only saw bout 2 amps coming from the pump, wave form was good, squeezed off return line and pressure barely touched 60 psi, already tried messing with the regulator..
Don't know what else to look for or test any suggestions before I drop the tank?
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Old 04-07-2011   #2
budfreak1
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GTA Year: 1991
GTA Engine: 350 TPI Automatic
Re: fuel pressure issues??

I'm guessing it's the regulator since it can go to 60 psi when you crimp off the return line which I would guess is about the max pressure it will produce. I do believe it runs at 42 psi stock with the vacuum line unhooked from the regulator.
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Old 04-07-2011   #3
tkrburnout
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Re: fuel pressure issues??

Do you kno of any other tests I can do to confirm its the regulator? I've turned the set screw and pressure has only gone up 5 psi from where it was to all the way in which was over a full turn.
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Old 04-10-2011   #4
skibum2100
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GTA Year: 1988
GTA Engine: Custom
Re: fuel pressure issues??

Turn the key to run but dont start the car and have the fuel pressure gauge attached, then squeeze off the fuel feed hose just after the pump is done priming. Note how long it takes the fuel pressure to drop to zero. Then do the same thing but pinch off the return line and note how long it takes the fuel pressure to drop to zero.
When you pinch off the feed line you are isolating the return side...the pressure regulator. When you pinch off the return line you are isolating the pressure side...the pump and pulsator (attaches the pump to the fuel line). My bet is one side will drop much faster than the other and I would start looking there for your problem.

Good luck, hope this helps.
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Old 04-12-2011   #5
tkrburnout
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Re: fuel pressure issues??

ya it does, i also have another test i found out about. but it requires me knowing what the flow rate of the stock fuel pump is, which i dont know? does anyone know what it is ive tried google and calling up dealerships and parts counters and their computers just show the part numbers and all of that. i could only find aftermarket fuel pump flow rates which are about 255lph
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Old 04-12-2011   #6
skibum2100
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GTA Year: 1988
GTA Engine: Custom
Re: fuel pressure issues??

The fuel pressure regulator diaphragm is an inexpensive item (Advance Auto Parts)...if your still using the original, it wouldn't hurt to just replace it. When your installing the new one, aligning the screws is critical. I tore mine by not paying enough attention to aligning the screws.
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