ordpete944

I have a late 85.5 NA. I took the car out and at high revs 5-6k the low oil pressure light went on along with the big red exclamation point light at the top of the gauges. But the oil pressure gauge is still registering pressure. Just did an oil change with mobil 1. Shut off car to investigate. Everything seems ok. I disconnected the ECM and cranked the car and the indication was still there. Cycled the key about 30 times and nothing. BTW, just did a P/S rack on the car. Any ideas??? (Oil quantity is full. Brake fluid is full. Oil pressure sender appears to be visually ok.)

Help!!!!!

Zero10

What is the oil pressure when running?
It sounds like one of the two wires to the sending unit has come off, and is shorting.
1 wire is for a pressure reading, the other wire is for the warning lamp.

ordpete944

Thanks!! I'll check that very closely. I looked from the top of the engine bay and it all looked ok. But of course that wouldn't rule out a broken wire. Thank you for your help.

livewirevoodoo

I had a similar experience.. When I first bought the car, oil pressure was pegged high at 5. Cleaned the contacts with some WD40, and that was all it took to get it working. One day after a car wash, I got the idiot light and lighted oil pressure warning. Seems like the undercarriage wash knocked the warning lamp wire loose.

Zero10

Yep, the wires go onto the oil pressure sending unit, which you can only see well from underneath. Check out Clark's Garage for more info on how to find it/fix it. His site is really helpful.

I think that's the wire, which has a little ring that is attached to the sending unit, then a spade terminal that slips on the ring. Terrible design IMO.