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Discussion Starter #1 (Edited)
Instead of having too many separate problems in one thread, I figure I'd start another.

Initial start-up with 32psi at idle and 42 psi of pressure with the vacuum hose off of the regulator. After driving for approximately 10 minutes/6 miles, I gradually lose all but a couple psi of fuel pressure.

From watching the gauge, anytime I attempt to give it throttle, I can see the pressure drop from 32 to 2 or 3 psi. If I coast for a while, it will slowly recover to ~30 psi. However, once the test drive was over it stayed at 10psi and would not recover.

I'm pulling 20.3-20.5 in/hg of vacuum while coasting.

My fuel system consists of a Walbro 255 and Racetronix harness that have 30k miles and bare metal grounds. A new wix/Napa gold fuel filter, new regulator and low mileage injectors.

I have inspected all of the wires going into the relay next to the tank and they appear to be just fine. I went around the intake and vacuum lines with a propane torch which didnt lead to any leaks.

Again, thanks in advance.
 

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Discussion Starter #2
Using the 12v jumper wire next to the fuse box made the pressure shoot up to 40psi.
 

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This is rare but first loosen the gas cap. I have seen blocked evap systems do this in other cars,
Air cant get in to replace the fuel in the tank.

It is likely not the above but easy to check,

More likely internal fuel line leak , voltage or ground at pump petering off,

My experience with regulators, they typically don't work up to the problem.
The only sure check is to work in a sight line or piece of clear hose on the return.

When ever the pressure is below where it should be, there should be no fuel returning .
 

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Discussion Starter #4
I'll give it a shot in the morning.

Any thoughts on the underhood relay slowly failing?
 

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I may have misunderstand your red jumper.

This is a racetronix in tank harness, or a remote relay , or both?

Are you saying that when you jump the red , the pressure is good, engine running and alĺ acts well driving?
OR
Jumping the red wire sitting not running makes pressure?

As you likly know, that red wire goes nowhere when the relay is energized.
It connects to the fuel pump wire though the relay when and only when the relay is NOT energized .
 

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Discussion Starter #6
The jumper wire used to prime the pump. It's located next the the underhood.
 

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I know exactly what it is and how it is wired.
It connects to the pump THROUGH the relay only when the relay is unenergized .
Normally when the engine is starting or running the red wire is disconnected because of the relay being energized.

What brings confusion to the mix in a 94-95 is the paralleled oil pressure switch .
Because of it, a 94-95 will start and run with a failed relay or relay control circuit.
My specific questions were to try and understand what might be going on.
If you dont have a wiring diagram, PM me with your email
 

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Discussion Starter #9
I may have misunderstand your red jumper.

This is a racetronix in tank harness, or a remote relay , or both?

Are you saying that when you jump the red , the pressure is good, engine running and alĺ acts well driving?
OR
Jumping the red wire sitting not running makes pressure?

As you likly know, that red wire goes nowhere when the relay is energized.
It connects to the fuel pump wire though the relay when and only when the relay is NOT energized .
Relay harness that is located near the tank.

With the car not running, I energized the red jumper wire pictures above and it then jumps to 40psi.

I replaced the under the hood relay with a Denso marked AC Delco relay this morning :geek:. I'm still loosing psi at part throttle, but it recovers to 32 psi instantly when I get off of the throttle. That in itself is a win.
 

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Discussion Starter #10
After sitting all night I checked the gauge and it was sitting at 12psi. I then started it with the new relay and it was 32 psi.
 

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Discussion Starter #11
The fuel pump is gradually losing power. Being a Walbro it's pretty evident that it's running or not. I heard the pump going from a mild EEEEEEEEEEEEEEEEE to an EEEeeeeeeeeee then eventually nothing and the car begain to stall.

This was in park and at idle after 30 minutes of driving.
 

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Discussion Starter #12
Cycling the key after the pump died did not cause the pump to prime.
 

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Discussion Starter #14
On the bright side, my bulkhead still looks good.
 

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Discussion Starter #16
From looking at the consistency and fine bits, my best guess is the sock.

The weird thing is that I never put anything in the tank other than gas and a little bit of Stable.
 

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Glad to hear you found it!
 

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It seems highly improbable any aspect or component of the system would still be incorporated into the design that disintegrates like that given the progression of technology through the decades. An introduced contaminant just seems more plausible, either that one directly or a reaction that you're seeing. If you still have a sample, then an outfit like 'Bob The Oil Guy' may be interested or able to shed light on it.

Glad you (hopefully) got to the bottom of the problem. Cleaning the rest from the tank may be a challenge from what I've heard about all the baffles in the design.
 
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Might be cardboard. Thanks for putting "solved" in the title, I wish more people would update.
 

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The fuel filter should stop much of that gunk from reaching the fuel injectors, but whatever chemical degradation was going on behind the fuel filter could still affect the fuel injectors as well.
 
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