Fuel pressure problems

[SPD TRP]

I am having some fuel pressure problems.

The symptoms are kind of wacky.
I can start it up but it quickly dies.
Narrowed it down to fuel pressure since my prosport fuel pressure gauge sweeps from 30 psi to zero.

So I unplugged the fuel pump resistor and bypassed it by jumpering the harness side of the connector. Kinda a shot in the dark, fired right up and idled.

So I assumed it was the resistor at fault, so I get another one and put it in.

All was good until last night, she stalled with the same symptoms. So I popped the hood, unplugged the resisitor, but this time I just plugged it back in. She fires right up.

Today I go in the garage to start it up and we have the same problems, will start but quickly dies as fuel pressure plumets.

Did some searching but didn't find any information pertaining to this type of problem.

Tested the resistor, still well within tsrm limits.

Should I just do the re-wire and hopefully be done with it?

 

[Knight_MKIII]

hmm, how old is your pump?

stock or after market FPR?

 

[SPD TRP]

hmm, how old is your pump?

stock or after market FPR?

Walbro gss 341
little over a year old

 

[blackgamer16]

Walbro gss 341
little over a year old

I wouldnt Depend too much on the Walbro. I had one for like 3-5 months, no heavy driving at all. But when i swapped to FFIM, IC and the works. I kept having problems of it not Getting the extra Psi per boost when am in full boost. Tried out another Aeromotive FPR, still same problem then went to a MK4 pump and Viola- Problem Solved.


If it was me, i would check the voltage at the pump, take out the cover in the hatch and have a DVOM on the power n ground wiring so ur getting the voltage you need, if you bypass the Resistor you should see a constant 12v or pretty close to battery voltage. IF it stays like that ur good. THan more than likely borrow a pump for a buddy. Dropping the tank is a breeze, make sure its empy and have a jack of some sort.

Let us know what happens.

 

[Knight_MKIII]

hmm, that's very weird. and if once you re-seat the resistor it works fine this means something is messed up with the circuit, maybe not getting enough power or something is wrong with the wiring (could be a bad ground)? I am a newb in case you didn't guess already but I am interested in knowing the solution as well.

 

[blackgamer16]

You'll know your answer once you tee in at the Fuel pump with a DVOM. Just watch what the voltage does. Simple fix. If you got the resistor plugged in it should switch from 9v to when you get WOT or some other trigger from the ECU to 12 V- thats the normal function.

If you bypassed it with a clip( resistor that is) it should always read 12 v because you just did the 12v mod.

And if you want to test the circuit just look at the Crynus and see which wire is which and ohm it out with a DVOM.

 

[SPD TRP]

I don't think it is a pump problem because I tested it at the pump with my dmm when we were having problems. I would get around 9 volts but it would go to zere volts and then cycle back up to around 9 volts, it just wasn't staying around 9 volts long enough for it to stay running although it would try. Once it would die, turn the key and it starts right back up but quickly goes through its stalling again.

What I did initially was to jumper the resisitor plug, fired right up.

One thing that I did not do was to leave the jumper in place for any period of time to see if the symptoms come back again.

Wayne

 

[p5150]

I think I am having the same problem although I have not had the chance to watch the gauge on my AFPR while the car idles. I have dual pumps and the resistor wired up in parallel. Initially, I had one resistor and it got WAY too hot. I wired in some resistors in parallel for low load conditions. The motor starts but the fuel pressure is dropping off.... or so I think. The engine dies a bit after it starts idling....