Fuel Pressure Problem Anyone?

[spongeboob]

Hey guys..for some reason my fuel pressure has spiked at about 45 psi and seems to be stuck there vacum off or on.. I thought maybe the diaphragm was gone in my regulator so I replaced it with an Accufab, I also replaced the gauge still no luck, I blew out the return line to check for any blockage still the same I checked the voltage at my inline pump and it was at 14.2v... I can turn the screw all the way in or out and the pressure doesnt change ..it doesnt change vacum off or on either.. Anyone have any ideas.. this is driving me nuts!!!

 

[TurboBuRick]

Have you tried another gauge?

 

[spongeboob]

Have you tried another gauge?

Yes the gauge is working tried it on another car and another gauge on mine.

 

[bison]

Does the pressure drop while cruising and opening the throttle? Maybe a loose hose connection in the tank?

 

[spongeboob]

Does the pressure drop while cruising and opening the throttle? Maybe a loose hose connection in the tank?

I haven't driven the car since this happened, what I did notice is i pulled the ground off of my external pump and voila , I could adjust the pressure, but the car needs both to run.

 

[bison]

I haven't driven the car since this happened, what I did notice is i pulled the ground off of my external pump and voila , I could adjust the pressure, but the car needs both to run.

Are you saying you couldnt adjust it down with the external on? If so you need a bigger return line or hole in regulator return is too small.

 

[spongeboob]

It was working, but it spiked and now it wont go up or down , vacum off or on, regulator and gauge have both been replaced..

 

[TURBOELKY]

did you replace the fuel pump before you had this problem? I had the same thing. I had the hose for the return on the vent tube of the sending unit. Stopping the fuel return. so it was way too high and not adjustable at idle, and would drop waaaayyyyy down under load.

 

[spongeboob]

did you replace the fuel pump before you had this problem? I had the same thing. I had the hose for the return on the vent tube of the sending unit. Stopping the fuel return. so it was way too high and not adjustable at idle, and would drop waaaayyyyy down under load.

No the pumps were both on the car and working fine, and the pressure stays the same no matter whats going on.

 

[Chuck Leeper]

Something wrong w/ the return flow capacity. Restricted flow back to the tank w/ both pumps on, causes adjustability problem w/ the FPR.
Reduce the flow by unhooking the 2nd pump, and the restriction in the return will allow enuf flow to "unlock" the FPR.
IE:
Both pumps on = 100GPM.
Return line can handle 50GPM.
Results: FPR adjustment is fubar.
1 pump on = 40GPM.
Results: FPR can be adjusted.

Bottom line = easy test.
Try a "free flow" return line, into a 5 gal jug. Both pumps on. FPR can control the flow? Look at the return...