Olds 88 (1998) Low fuel pressure

“I haven’t put the fuel pressure tester back on it (been busy) so I don’t know if the pressure is still low or if these other things are even related.”

Maybe you should do that…

When you replaced the pump, you also replaced the silicone (or whatever) flex lines that connect the pump output to the hard-line exiting the tank didn’t you?

more diagrams. Hope this will help.

Question: What do a fuel pump, windshield spray motors, rear defroster, power seats, power windows and power locks have in common?

I’ve been messing around with it and any time one of these is activated, the engine stalls out. However, other big load systems (headlights, blower) seem to have no effect. Interestingly, the rear defrost relay is on the same panel as the fuel pump. I’m not sure about the rest. (Can’t find a relay position diagram for the life of me). Would a panel like that have a single ground for all relays?

One more idea: if the tank vent system is plugged up after all there years, maybe a good bit of vacuum in the tank is affecting the pump. To test this, loosen the gas cap and see if the fuel pressure behaves. You may or may not get a CEL on, but it is worth a shot.

It turns out, these items (or at least most of them) share a common ground bus. I googled the car model and the items I mentioned and found 3 posts of people who had the same issue. They said there is a ground bus under the carped between the driver’s seat and the parking break. After some digging, I found it. Rather than using the factory part for replacement, I bought a ground bar from home depot. I put that in and heat shrinked insulation over it. I can now use my rear defroster, move my seat and roll up my window all at the same time without killing the engine. As for the fuel pump, I haven’t checked the pressure, but it has not stalled out all evening driving it around town. That’s pretty unheard of. So after spending countless hours and hundreds of dollars, it was fixed with a part that costs $4.93. Oh boy.

Thank you all for your help in guiding me through and saving me some money along the way. You all are by far the most helpful forum out there!