Oil Pressure / Gauge

[KAHruzer]

I've a recently acquired 1991 C1500 V6, 4.3L w/5-spd manual.

It's got that dash cluster I'm not particularly fond of, but the gauges
are wheel edge type with white fill indicating level for fuel, oil pressure, speedometer, etc.

Anyway, the Oil Pressure is the only one of concern. I do know the speedometer
always going berserk is due to the VSS, which I will soon fix.

When I start the engine and as it idles after warming up, it shows a pretty
steady 30psi. As soon as I accelerated, no load and normal, it pegs the
oil pressure off the end.

Is this gauge driven directly by oil pressure or electronic signal?

High oil pressure is something I've never had to deal with. IIRC, this could
indicate clogged passages and such.

The engine runs great, holds temp and doesn't seem to have any problems.
How can I tell if the gauge is bad? I guess I should put a test gauge on it
and see what the oil pressure really is, huh?

Any helpful tips appreciated.

[PitKrew]

This is a service bulletin from General Motors, not sure if it addresses your concern completley hopefully it will help in soem way or another
BULLETIN NUMBER:
93-8C-28

SECTION:
8C
NUMBER:
2
CORPORATE
REFERENCE NUMBER:
268304
DATE:
November 1992
SUBJECT:
INCORRECT OR ERRATIC OIL PRESSURE READINGS (INSTALL NEW OIL PRESSURE SENSOR)
MODELS:
1990-93 ALL LIGHT DUTY MODELS
Owners of some 1990-93 light duty trucks may comment that the oil pressure dash gauge reads high, has erratic movement or is inoperative.
The internal resistance wire in the oil pressure sensor may not be properly supported, resulting in an intermittent open condition.
SERVICE PROCEDURE
Check for normal causes of high oil pressure gage readings (high resistance or open circuit), such as a poor ground path caused by loose sensor mounting, oil cooler adapter loose, or poor electrical connections. If no cause can be found, replace the oil pressure sensor following the procedure.
1.Disconnect the negative battery cable.
2.Remove the wiring harness connector from the oil pressure sensor.
3.Remove the oil pressure sensor.
4.Install the new oil pressure sensor.
5.Connect the wiring harness connector to the oil pressure sensor.
6.Connect the negative battery cable.
PARTS INFORMATION

New Oil Pressure Sensor Part Numbers for the 1990-93 models
Parts are currently available from GMSPO
WARRANTY INFORMATION
For vehicles repaired under warranty use labor operation N2220.

[KAHruzer]

Thanks PK, probably would've never found that.