oil presure

[diverman555]

I have read that on a M923A1 the cummins engine will have about 15-20 lbs oil presure at idle. my guage shows 85 lbs all the time it's running, whether at idle or at 2000 RPM.
Any ideas what this could be?

 

[paramedic7831]

Does the guage show 0 when switched on and not cranked?

 

[diverman555]

Yes

 

[dozer1]

When I have oil pressure gauge concerns, I like to get a new mechanical one (which are pretty inexpensive) and hook it up to wherever they read the oil pressure on the engine. That means remove the electric sending unit if the truck has an electric gauge, and hook up the hose for the new gauge there. You can then see what is really going on for oil pressure. If everything is OK, you can then go on to change the stock sending unit or gauge. If your truck HAS a mechanical gauge to begin with and it reads incorrectly, the gauge is no good.

 

[rrrr]

If you are not getting the truck up to operating temp for a while to warm up the oil it will be high. My truck will peg the gauge for a while then after 30 minutes of driving it will be 40 at idle. Takes a while to warm up. Big motor lots of oil

 

[diverman555]

I disconected all the wires at the sending unit. gas gauge not working took off wire, sprayed electric cleaner in and on post, put that electric lube on and reconnected wires, now all gauges work fine. don't know about trans gauge yet have not drove it enough to get trans warm.

 

[cranetruck]

FWIW, the oil pressure gauge (also the fuel level) works on low resistances, about 30 ohms for 60psi. If the connection to the sending unit is cut, you will see a full deflection.
Increased resistance in the connection to the sending unit will through off the reading...