Oil Pressure Gauge or Oil Sending Unit?

[hionbusa]

Hello,

86 Carrera 3.2
In process of updating my instrument bulbs to LEDs, I discovered that the oil pressure gauge now goes to max ( 5) on ignition ON & Zero on ignition off. Stays at MAX After engine starts. Read some threads that could be related to a poor connection or grounding issue.

Everything worked flawlessly before attempting this mod so below are my trouble shooting steps:

Switch back to stock bulbs
Disconnect & reconnect the battery: nothing
Tap the gauge with ignition ON stuck at 5: Doesn’t move
Make sure all 3 connectors are not short (photo) high probability of the issue
Tap the oil sender unit gently, check the ground wire and the connector

On note : When connecting the red wire only it goes to max (5).




Any thoughts before diving further into either a bad gauge or oil sending unit.

Thank you,

[wazzz]

Probably not a short, but a bad connection between the pressure sender and the gauge. What you describe (needle pegging to max) is what you get if you disconnect the wire at either end.
If you didn't work on the sender in the engine compartment, the wire end to be checked first is the one at the gauge. Make sure you plugged everything as it should.

[hionbusa]

I will check again.
I did notice that some 911 models have wires connected directly to the while mine has a harness.
Merci Beaucoup ☺️

[nospiners]

same issue i had was fixed by checking and cleaning all the brown ground wires behind the gauges,,

[Showdown]

Grounds should always be on the list of things to check when dealing with Porsche wiring.