Oil Gauge Help......

[Hotrod86]

Hi, new to the Site. I have a 1985 C10, bought a few weeks ago without an engine. I am on my way to fix things and when I bought it there was an aftermarket mechanical oil pressure gauge mounted on the lower side of the dash. I choose not to leave it in. I put both oil pressure sensors and switches in, so the choke works correctly. I did see on utube about the resistor on the back of the gauge being open. So, I took the gauge out and the resistor off the back side of the gauge, its open. So, I ordered one from LMC. correct year. the ohms on the new and old are different. the new one does not come with a resistor on the back. one oil pressure gauge reads 60. one is at 15. Please help. Thank you.

 

[Redfish]

I don't completely understand your question. If the old resistor is open it should have a different ohm reading than the new one. Or can you read what the ohm value was supposed to be?

At what engine speed are these two different gauges reading 60 and 15psi?

 

[Matt69olds]

There are different oil sending units calibrated for different gauges. Most are 60psi, there are a few for 80 psi dash gauges. They are usually stamped on the threaded end of the sender.

Put a 80 psi sender gauge cslibrated for 60, the pressure will read low. Put a 60 psi sender on a 80 psi gauge, it will read high.

The fact someone put a aftermarket gauge under the dash suggest there was a problem. Ground the wire to the gauge, the needle should read zero. With the wire disconnected, it should read full tilt.

Inspect the printed circuit board on the back of the gauge cluster. Make sure none of the copper traces are damaged.

 

[dvdswan]

There are C/K oil gauges that go 0-60, I don't recall ever seeing 0-80, but that doesn't mean they don't exist. The 0-60 gauges come in the 2 different prints so it would match your dash. The L-H gauges, IMO, are idiot gauges/lights for those that can not comprehend a number of pressure.

 

[wlwarnke]

0-60ohm sensor = 0-60 psi

The newer truck with 80psi gauges or still 0-60ohm sensors.

Sorry I can’t recall the value of the resistor on the gauge itself.

 

[Snoots]

You must be registered for see images attach

FYI, the 89 ohm yellow is on the back of the gauge, just NOT to the GROUND side! Forget the 80 on this illustration.