oil pressure issue

[jbelcher0628]

i got a 93 cummins 275k miles and the oil pressure gauge says that it is low but not sure if its the sensor, gauge or what..truck runs fine though..while i am running down the road the oil pressure shows what it should be showing at idle. when it is cold its fine, which i understand that it should be, but it aint the oil or filter cuz its all new. any help is appriciated

 

[ameristar1]

Check the pressure at the sending unit port with an accurate gauge. Then drive it around, get it good and hot and see if the variation is still the same. I know after I got mine hot, the pressure would run low and the light would flicker, but like your truck, it ran fine. Never had a problem.

 

[rebel_horseman]

Does the volt meter read lower than normal? If so more than likely it's the ground wire. There should be a 110-12ga black wire running from the negative terminal of the battery to the front radiator support. The wire should be about 8" long. Check to make sure teh connection is secure on both ends. I had a similar problem a while back that caused the gauges to read low and the lights to flicker slightly.

If that is all good, you can change out the oil pressure sensor. If I remember right it was like $20 from NAPA. The sensor is located a few inches behind the vacuum/power steering pump on the driver's side of the block. It's recessed up into the block slightly so you'll need either a thin socket or an open end wrench. Be careful as the sensor housing is plastic while the bung that screws into the block is metal. If your socket gets off center just a little it will break the plastic housing.

As a reference, at idle the volt gauge and pressure gauge should be on or just slightly below the first tick mark in the normal range. The volt gauge should be right in the middle when the truck is running. The oil pressure gauge should read all the way to the next tick mark when cold and anywhere in the middle of the gauge under normal operating conditions.