My 88 “Rosie” has been having problems for months. It hesitates, stalls, and sometimes backfires. This is an intermittent problem, though it is happening more often lately. I took it to local auto shop and their computer showed Rosie was throwing a misfire code as well as a lean code. I took it 3 mo…

Yes, turned the ignition (but not start) first to let the fuel pump “charge” the lines. The fuel pressure went to 55 then it drops to 48 after starting the engine. Then at some point it also dropped to 15 Psi While Running. Yes, I replaced the fuel pressure regulator.

You might be thinking along the right path about the relay. One thing I would try is to swap the FP relay with another relay not important to engine operation and see if it helps.

OK. I meant to check if there is vacuum at the fuel pressure regulator. If not you have a blocked vacuum port at the intake, just follow the line and use a can of fuel injector cleaner to clean it. Check the hose for cracks. There is not too much to say, assuming that the car is in shape, no accide…

Since I last posted, I did put the fuel pressure tester back on it. Sure enough, it was struggling at 18 psi. It is also still throwing a P171 code, which is lean bank 1, I believe. Thank you Pete, I’ll check out the relay. Castironman, I did check the vacuum hose. It was pulling a vacuum. I also …

Did you replace the fuel pressure pulsation damper when you replaced the fuel pump? It’s a check valve located on the fuel pump assembly and if it fails it causes fuel pressure to bleed off.

UPDATE: My fuel relay is hot. Not melting, but significantly hotter than it’s neighbors. Been reading around on other forums, some guys are having similar problems and one symptom in particular caught my eye. They say their power windows don’t work when it happens. Random. But Rosie has been doing…

Find the return line to the tank from the fuel rail, pinch it off, recheck your fuel pressure after it sits and see if the pressure drops. If it doesn’t drop then the problem is in the tank, more than likely the pulsator.

Ground for fuel pump relay is G101. This ground is attached to the engine next to the oil pressure switch. Oil pressure switch is attached to rear of timing cover. For some reason I can’t find diagram for power windows.

If your fuel pump relay is hot, then either its defective, or the socket it is in is loose. Check the socket and replace the relay and you may fix it.

Olds 88 (1998) Low fuel pressure

Power/Fuel

mitchellt.eng February 18, 2011, 7:14pm 9

I believe the pulsator was built into the new fuel pump. I’d feel like a doofus if it wasn’t, but I’ll tell you one thing, it would not fit. The new fuel pump was the length of the old fuel pump and the pulsator together. It had a plastic component on the top that the old fuel pump did not have. I had to assume it was the pulsator.

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Olds 88 (1998) Low fuel pressure

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