spillmk1

Hello,
Just bought a nice 1988 944 with 64,000 miles and all records. Everything on the car works.....except the oil pressure gauge.

The gauge stays on zero even with the sending unit unhooked.
I ohmed the wires back to the gauge and no shorts or grounds.
I cleaned and reconnected all the grounds above the drivers kick panel.
I removed the instrument cluster and pulled/cleaned all the plugs.

Still the gauge stays on zero with the sending unit unplugged.

What have I missed??
Is there a way to check the gauge??

Thanks in advance for all your thoughts/help.

Keith

odonnell

Firstly, welcome to the forum!

You can indeed test the gauge as well the sending unit: http://www.clarks-garage.com/shop-ma...ect-19.htm#oil

OPSU goes out all the time, apparently. I just had a episode with my oil pressure- same symptoms. It got cold out and suddenly no oil pressure. I recommend getting OEM sender unit, the Uro and VDO are flaky (found out after I ordered a Uro). Pump wrenches are a must-have! Link

Are you sure you do indeed have oil pressure? If you do, it's the sender. If you don't, it could be the pressure relief valve being stuck open, which is a very real possibility if you recently had a brisk temperature change. O-ring could be improperly seated.

spillmk1

I guess I was under the impression that with wires unhooked to sending unit, the gauge should read full scale. If gauge stays at zero, then that eliminates the sending as a problem.

Is that not correct?

odonnell

That's interesting, the link I shared also has a write up for testing the gauge.