Denali Fuel Pressure Low

[eg30.06]

So as alot of you have seen i bought a 99 Denali with a bunch of electrical questions. I have not run it since I bought it and today was the first. Had low fuel pressure from the start 10 psi max. Replaced the fuel pump, same. Fuel filter replaced, same, relay same... said the hell with it, ran straight 12v to pump, instantly worked and started rite up. Is there a common place these chafe wires causing bad connections? I checked voltage and I'm getting 12v at the plug..

 

[someotherguy]

Sounds like weak ground. It's attached right there at the frame, near the sending unit. Seeing 12V with a meter doesn't draw any current like the pump itself does.

Richard

 

[SUBURBAN5]

Does your gas needle work on the cluster?

 

[eg30.06]

Yes fuel gauge works. Ill check the ground tomorrow.

 

[SUBURBAN5]

The fuel pump connector a 4 pin right?

 

[eg30.06]

The fuel pump connector a 4 pin right?

Yes

 

[SUBURBAN5]

You said you replaced the fuel pump. Did you use a original style or did you convert to the newer style?

 

[SUBURBAN5]

Also when you connected it straight to the pump what was your psi?

 

[eg30.06]

Also when you connected it straight to the pump what was your psi?

I'm not sure what the new style is, it looked like the one I replaced lol. Was 65 70psi when hooked to a battery.

 

[SUBURBAN5]

Wow awesome pressure. Without a wiring diagram I'm not able to point out the route. However you said your recieving 12v. Check the other pins to norrow down your issue. I have a feeling the ecu or ignition is not signaling the pump. I may be wrong but having a 99. You got some anti theft features like mine. I'm just not sure on what communicates with what. Maybe the electrical wizards will chime in..