My GTA has always pegged the oil pressure gauge since I've had it. Figured the gauges were off or one of the bypass valves was stuck. Drove the other day and she read 40psi at start up and after driving and warming up, idle sets at 20-25, and goes up to 30-40 while driving. We're headed out to power tour today and it's got me thinking... It all sounds in spec, but not my normal that I had gotten used to. Car only has 126k on it and is stock, running great, no noises. Could a bypass valves that was stuck, unstick? Did the gauge just now to start displaying accurately? Should I change the sending unit? Should i just go.... All replies greatly appreciated..

 

The bypass valve is in the piece that the oil filter screws on to. Did it unstick? I doubt it. I doubt it was ever stuck. Possible issue with a wire or the sending unit? Possible. Best thing to do is take a GOOD mechanical gauge and test it. That way you have a reliable number to know as opposed to assume. Then you know if you have and engine problem or a gauge problem.

 

Yes, I had an issue with my Oil pressure guage wiring. This year I finally sorted it out. I used a bell sender for a 85 TPI car. All was well at first, then my brand new engine seemed to start getting VERY poor oil pressure when warm. Like 3-5psi. But I didn't hear any valvetrain noise.

The first step was to put a mechanical gauge on it.

Mechanical gauge showed about 20 psi hot @ 900rpm idle, spiking to 30-40psi between 1000-2000rpm. Which is more than enough to make me happy. So now I know its either the sender, or the wiring thats got a problem.

The easiest first step in diagnosing a possible oil pressure issue is to put a mechanical gauge on it. That will tell you the true story.

 

Thanks guys,

No time to do the mech gauge this time, had to leave for power tour. Did change out the sender unit. Helped a little and in five hours of driving to Memphis in 100 degree weather she stayed at about 37psi at 75mph all day. At idle would set at 25-30psi. I believe all is well, just got used to seeing it pegged all the time. On to the tour and the next stop...