454 Low Oil Pressure

[Crimsontide14]

Ok guys, I recently purchased a 1991 V3500 with the factory 454 in it. My problem is that the oil pressure gauge is only reading around 15 psi all the time (no matter what rpm). I have changed out the oil pressure sender and changed the oil, but have not no change in the pressure reading. I filled it with 15W-40 Rotella and put a new Purolator filter on it. I have tried to run it as little as possible since I noticed the problem. I plan on getting a mechanical gauge to double check the gauge in the dash. As of right now I can't hear any ticking or knocking, but it is kind of hard to do because the exhaust is fairly loud. Do you guys have any tips on what I could try to get the oil pressure right again? At this point, I am just hoping I don't need to start saving up for a rebuild or new crate.

[bd]

...I plan on getting a mechanical gauge to double check the gauge in the dash....

Do this ^^^^^^^.

And, welcome to the Forum!

[emod20]

you are right on about testing with a mechanical gauge that would be first step. its 15 with gauge all the time thats an unusual problem. usually lower at idle and goes up somewhat even with low oil pressure problems. one thing i have seen happen is a piece of dirt or something causing oil pump bypass valve to stick partialy open. usually the normal bearing problem have real low at idle when hot. just my 2 cents worth

[Crimsontide14]

Today, I hooked up a mechanical oil pressure up to the port for the oil pressure sender. At idle the mechanical gauge read around 40 psi and would increase to over 60 psi when I revved the motor. So, I'm pretty sure that my oil pressure is OK for now. My new question is what do you suppose is wrong with my factory gauge. When I disconnect the oil pressure sender, the oil pressure gauge pegs out at over 60 psi. Do I need to invest in a new gauge or do you think there might be a loose wire or ground somewhere? The current gauge reads the same with both the old and new pressure sensor I have.