Hey everyone, I've been lurking these forums looking for some answers, but I'm having difficulty with a few things, so I thought I create a post about it.

I was having issues with fuel delivery for a while, it was intermittent, just cutting out here and there. The fuel filter has been replaced.

After looking through these forums, I decided to test the inertia switch. The button on top was up slightly, it can go down further but won't stay down...if I move it up it doesn't stay up either. So I jumped the connection and put a test light on it.

When I turn the key on, there are no pulses or anything, can't hear the fuel pumps turning on at all. But if I try to turn it over, the light comes on, so at that point there is power going through at least that point.

It turns over, and runs for about a second then dies. I was just seeing if anyone had any info about what could be causing it to not send the pulses to prime the pump when I turn the key on. But still send power when I turn the engine over

EDIT: Also it was doing this with both tanks


Edit: Jumped the relay, the light where I jumped the inertia switch was on the whole time it was jumped, didn't hear any fuel pumps running got down and couldn't feel anything either, so bad pump?

 

Key on should cause fuel pump relay to close for 2 seconds, then it will not close again until engine starts(above 600rpms), not sure why yours isn't doing that, but relay is closing when cranking, which it shouldn't do.
Maybe '88 computer software is different.

Yes, if you put a jumper on the Fuel pump relay or digital terminal and get power at inertia switch but pump doesn't come on then pump is "most likely" bad.
I think the '88 was the last year of the high pressure pump in the frame rail and then a low pressure pump in the tank.
in '89 there was just one high pressure pump in the tank.

Both pumps not coming on would be a wiring issue vs a pump issue, to long of odds for both pumps to fail at the same time.

If you have dual tanks your switch could be bad or intermittent

 

Thanks! Just got back home from the weekend, so I'm taking another look tomorrow. I'm gonna test the connections at the high pressure pump to see if power is getting down there, I know that pump isn't turning on...as for the two low pressure pumps, I think I just can't hear them well, both tanks are full so they may still be coming on.

The connections on my relay looked pretty nasty so I'll clean those up before getting a new one

 

Ok, the power was working at the fuel pump, the weird thing is....this time the in line pump came on..i think I heard t he low pressure ones to, this was after jumping the relay....still wouldn't start though.

I think I'm gonna get a new relay first, and see what happens. Last time we jumped the relay the pump didn't come on, and power was going past the inertia switch, so I'm not sure what's going on exactly now, Still doesn't prime when I turn the key on...but I was doing it by myself and I may not have been able to see the light quick enough

 

There is a splice near the high pressure pump, this can get corroded and become intermittent.
At the factory they just spliced a wire into the original low pressure pump wiring to power the added high pressure pump, over time and moisture................well, it can go bad.

 

Yeah, I had forgot that I cleaned a plug that went to the high pressure pump, when I was testing it, that must have been it. Also Looking at it today, I turned the High pressure pump, and the line going from the pump to the fuel filter just slipped right off the pump...the plastic pin was still in it, I'm going to get another hose as well. After the relay and the hose, I don't see any reason it wouldn't start now that the pump is coming on.

Thanks for the reply, I'll see how it goes!