Getting DTC codes and idling up and down.

[bszopi]

Hmm... Well, that is definitely the OPSU. And its definitely the gauge one (longer). Why it only has a single wire coming out of it baffles me. Unless, for some odd reason, you car doesn't have the interface with the fuel pump.

[cutlass supreme FE3]

Hmm... Well, that is definitely the OPSU. And its definitely the gauge one (longer). Why it only has a single wire coming out of it baffles me. Unless, for some odd reason, you car doesn't have the interface with the fuel pump.

Well the vehicle is a 1988 Oldsmobile Cutlass Supreme International with the 2.8L MFI motor. I had this car since new and that is the original OPSU and I never had it replaced. The dash is the blue lit digital type where there is a gauge not a oil light.

So if it does not have the interface with the fuel pump then the relay power output goes directly to the pump?
I get the 54 code but what would cause my idle to go up and down? I have replaced the fuel pump relay with a new one and problem persists.

[cutlass supreme FE3]

okay i went outside today and the temperature is -6 degrees celcius.

I have to crank the starter three times while pressing on the accelerator to get it to start. It will not start without the accelerator depressed.

once started the oil pressure gauge shoot up which is normal at cold starts.




the idles is at 1000 rpms


idles at 900 rpms


now at 1100 rpms




900 rpms

gas is full and alternator charging full


original mileage in kilometers and also you can see the idle dropped two bars



idle back up 2 bars 200 rpms


idles at 800 rpms now





anyone have a clue what could be wrong?

Now the focus is the fuel pump and i need to get a fuel pressure test done tomorrow.

[cutlass supreme FE3]

I was just outside and I did a quick test for the fuel pressure.

There is a shraeder valve on the fuel rail and i just depressed the valve down to see if any fuel comes out.
There is no gas at all. Okay, then I turn on the ignition for 5 seconds and off a few time so the fuel pump is supposed pressure the fuel rail. Wrong, the fuel pump does not operate at all. Okay, I crank it two times but it does not start and I got and depress the fuel rail valve and now there is fuel coming out.
I go and crank a third time and yes now it starts.
Now I got to figure where the fuel pressure is leaking from? most likely one or some of the injectors is leaking.

I'm slowly trying to pinpoint the problem area.

[bszopi]

Take the vacuum line off of the fuel pressure regulator and see if gas comes out of it. If yes, then you have a bad regulator.

[cutlass supreme FE3]

Take the vacuum line off of the fuel pressure regulator and see if gas comes out of it. If yes, then you have a bad regulator.

I do this with the car running or off?

thanks for your help

[bszopi]

Hmm... I dunno. LOL I'd say try it first with the car off. I'd hate to say do it with the car running, and then have it be ruptured and gas starts spraying out all over a running engine.

[cutlass supreme FE3]

Hmm... I dunno. LOL I'd say try it first with the car off. I'd hate to say do it with the car running, and then have it be ruptured and gas starts spraying out all over a running engine.

pic of the motor in the morning



with the car off not started during the morning = no gas

started the car and pulled off the hose = no gas

shut off the car and waited 2 minutes and pulled off hose = no gas

[cutlass supreme FE3]

anyone confirm the fuel pump check valve is faulty?

[cutlass supreme FE3]

going to get a fuel pressure gauge

[cutlass supreme FE3]

here is a video of how the idling is.