oil gauge jumping around

[coxfmly]

Hello,
While driving my Sub on the freeway at a constant 65 MPH, I noticed my oil gauge jumping quickly from 20 to 40 psi ?? this lasted for about a minute or so and then leveled off at its normal cruising reading of 40. The truck has a instrument reading (factory) of 45 cold and 25 hot. Sub has 200K, new heads and fresh oil.

Thanks..

[racer55]

Sounds like a bad connection or a failing OPS.
If you need to replace the OPS only use the GM dealer AC DELCO version,aftermarket senders are not as reliable.

[jhornsby3]

I had the same issue and found the OPS to be bad. And like Racer55 said the after market ones can be iffy. Used an Autozone one and it lasted a week. Went to a Crappa one and it lasted for a month. Stick with the AC Delco. I put a fuel pressure guage after the "T" valve with another "T" valve so I could check the pressure and to watch the OPS for a working condition.

John

[coxfmly]

I'm going to pick up a GM OPS tomorrow and let you know how it goes. I think i'm going to replace the boost control solenoid and resistor #9 while i'm at it. Sub was bucking a bit after 3K on hard pulls.
John, as far as the "t" valve, are you talking about the valve next to the upper intake hose? I have opend this up at idle and the engine runs fine. Is this the line which should have 3-5 psi?
Thanks,Paul

[JohnC]

Don't waste your time replacing the resistor. It's very unlikely to go bad and wouldn't have any noticeable effect if it did.

[coxfmly]

I replaced the OPS and the boost control solenoid, 2 day nightmare! The OPS wasn't a 27mm or any other deep socket I had. Tried everything...eventually I broke off the body and unscrewed the brass fitting which was going into the block. Tough part was unscrewing the clamp which holds the fuel lines in place. Anyway, after I removed it I still dont have a socket which would fit the old OPS ??.

With the new unit installed my oil pressure jumped almost 10 PSI all around. Seems to run strong but still seems to cut off on hard pulls. Its not shutting off but I can hear a small "miss". Kinda strange since I can't duplicate it every time. The switch helped but I might need to time the IP now. local shop said they could do it for $140. Other that than the truck seems to roll right along.

Thanks.....