Oil Pressure Gauge is Pegged

[blackandredvette]

The last couple times I drove my '81 the oil pressure gauge pegs out. It comes back down after I shut the engine off but pegs as soon as I fire her up. Any thoughts?
thanks,
Brad

 

[bill81vette]

Bad switch..
it's located under the distributor..
besides its easier to change this 1st!!!!

 

[blackandredvette]

Okay, I have replaced the oil switch and also replaced the oil gauge and still have the same problem. Dunno, it looks like its time to take her to the shop.

 

[Peer81]

The only thing that I can think of now is a shortage in your wiring.

Groeten Peter

 

[damoroso]

Sounds like a grounding problem. Is the engine doing anything that would give you an indication somethings wrong? I can't think of anything in the oiliing system that would cause pressure to be that high all the time. There's a bypass for a clogged filter, a bypass in the oil pump, and in the engine, it's one big oil leak...I can't see how the actual oil pressure would be pegged if you didn't change anything in the engine.

 

[Hib Halverson]

First thing to do is stop all this guessing.

If you replaced the gauge and the sender and pressure is still "pegged" let's look at some basics.

1) Install a known-good mechanical gauge in place of the sender, fire the motor and observe the pressure. Does it match the pressure trend you saw before? If it doesn't then you need to trouble shoot the gauge wiring.

If it does match the regular gauge, then look at other issues. What weight oil are you running? If you're using a 10W30 or a 30, then the pressure relief valve in the oil pump may be stuck or sticking. That valve is what regulates maximum pressure and if it "sticks" oil pressure will be very high.