Oil Pressure "128 psi" - incorrect reading

[mrsilv04]

1999 Buick Park Avenue. Non-supercharged with optional driver information center.

The gas gauge quit on the instrument cluster, so the shop took it out and took it to the GM dealer to be sent in for rebuilding. This was after they tried to fix the car with 2 different used clusters... one wasn't the right one, and the second one had a bad gas gauge as well.

3 days and $300 later, instrument cluster is back from the GM dealer. It is reinstalled and the gas gauge works fine.

Only problem is now the oil pressure reading is at 128 psi... engine running or not.

Shop is sort of at a loss as to what isn't right with the oil pressure reading. This was a bit of a nightmarish fix to begin with.

Suggestions as to where to start?

 

[Corvette Owner]

Happens all the time on Corvettes, your oil pressure sensor is bad. Hope it is easier to replace than on C5 Corvettes, you have to pull the intake manifold on those.

To check this, turn on the ignition, but not the engine, if your gauge reads any pressure, the sensor is bad (or wire could be shorted). Most likely a bad sensor.

Be sure you torque ONLY to the correct level (15 ft-lbs) and clean off the electrical connector if it is oily.

Good Luck !

Whoa, I re-read your post. See you stated it was high with the motor not running. BUT, I can't believe your sensor would go out just as you replaced your cluster, my bet is now on wiring in "new/re-worked" dash cluster.

 

[andyd]

Corvette owner, so, while the instrument cluster was out being fixed, the OP sender coincidentally failed? Possible, I s'pose, but unlikely. More likely, the OP gauge has had a ground put to it during the repair. Repairs of this sort are a PITA and not a run of the mill repair for a shop. If it worked before the repair, and it doesn't work now.... Been there done that, so I know the deal. The shop is gonna blame the rebuilt part, the rebuilders are gonna blame the install. The job is gonna stall unless you bite the bullet and settle for a 10 yr old car with a bum OP gauge.
My car's Instrument panel can be taken out in 10 minutes and swapped back in just as easily. That is not usual. Dashes are generally bad to work on. Ive had it out a few times. But, the gauges and connections are fragile. My average is about 50% success rate on fixing a gauge fault.

 

[mechtech2]

In any event, an oil pressure sender unit is not much $ and can be installed by yourself.
It is be worth a try in your situation.
Is it throwing parts at it to fix it? Yes, but there a good chance that is what's wrong, as it is what's left.