Faulty oil pressure sensor?

[mlipmd]

Ever since I got my '90 ZR-1 seven+ months ago the oil pressure has read ~70 psi as soon as the car starts, at idle, at any throttle speed with no more than a tiny 2-3 psi fluctuation if it revs up.
I assume this means the OPS has bit the dust and should be replaced. And that is the sensor standing upright to the left of the oil filter, correct?
Anything else that could cause this, anything else I need to look at? The connection is clean inside and I doubt a poor electrical connection is the issue. Do I bother trying to measure the resistance at various engine speeds or do I just replace it for < $40?
Car otherwise runs great with no issues.

[GOLDCYLON]

Ever since I got my '90 ZR-1 seven+ months ago the oil pressure has read ~70 psi as soon as the car starts, at idle, at any throttle speed with no more than a tiny 2-3 psi fluctuation if it revs up.
I assume this means the OPS has bit the dust and should be replaced. And that is the sensor standing upright to the left of the oil filter, correct?
Anything else that could cause this, anything else I need to look at? The connection is clean inside and I doubt a poor electrical connection is the issue. Do I bother trying to measure the resistance at various engine speeds or do I just replace it for < $40?
Car otherwise runs great with no issues.

Just replace it these go out ALL the time :cheers:

[mlipmd]

That's my intention. I'll let you know what happens when I get it done.
Was just looking for a little support or other advice.

[GOLDCYLON]

:)That's my intention. I'll let you know what happens when I get it done.
Was just looking for a little support or other advice.

You have it here just trying to save you some time. I have replaced 4 of these on the 2 Zs I have. They fail all the time so it is somewhat common.

Key indicators of failure are that they all peg or the drop showing less that 0 oil pressure. Correct it's upright of the oil filter.

[Corvette95]

I believe there are multiple OPS's out there. I think there is a specific part# to order if you want your analog gauge to read pressure more in the normal zone than standard replacement OPS that tend to show the pressure higher than the original gauge. I don't have the actual part number handy but I am sure someone here will have it.

[mlipmd]

My OPS is black so I assume it's been replaced at least once. Is the socket size still a 1 3/6" if it was replaced, or would/could a PO replace it with a 1 1/16" sensor?
Are the thread sizes that screw into the filter housing the same, just the size of the base to grab on to is different?

It's hard enough to get a sensor socket without having to buy 2 of them.

[mlipmd]

Is there any difference in the sensors with the base either 1 1/16 in. size vs. 1 3/16 in. size? Will either sensor work the same in my '90? Seems like all the sensors are 1 1/16 in. in size now and all the suppliers say they are all compatible with the '90-95 LT5s. If so,
now I have to get the 1 1/16 size socket as the 1 3/16 I got is too big to fit what's in my car or the new sensor I was sent.

[mlipmd]

Posted also on the Corvette Forum - any thoughts on here?
So I put in a new AC-Delco OPS and the oil pressure still reads ~70 on startup, then down to maybe 60 after it warms up, back to 70 on revving up the engine a little. Maybe that's due to a 40 wt. oil in there instead of 30?

Or the OPS is not properly calibrated for the LT5. Gonna leave it like that for now.
As another aside - how many wires are in the connector to the OPS? Mine just has one wire leading into the top of the sensor, I assume that's just to measure the resistance inside?

[mlipmd]

FYI- if anyone cares-
Went for a 20 mile ride today and the OPS and the oil temp sensor seem to be working OK and I learned a few things too. First of all, the reading of 70 on startup is what the last reading was on the analog gauge when you last shut off the engine, before it starts. If you turn the key to OFF again and then to restart, the gauge will read 0 before the engine starts, then the pressure reads 70. This is with cold oil. Because of the volume of oil in these cars (~9 qts.), it takes a while for it to warm up and reach operating temp - maybe 10 miles of driving or so. After the car is warm, the idle pressure in my engine drops down to the 30-40 range on my gauge (about 1/3-1/2 way up the scale), and then goes up to 60-70 when revved up or driving. And my oil temp only goes up maybe to 1/4 the way up the gauge, also takes 10 miles of driving or so to get up to there.
So everything seems to be working as it should and I never really noticed that before, that it takes so long to get the oil up to temp.

[staminqia]

FYI- if anyone cares-
Went for a 20 mile ride today and the OPS and the oil temp sensor seem to be working OK and I learned a few things too. First of all, the reading of 70 on startup is what the last reading was on the analog gauge when you last shut off the engine, before it starts. If you turn the key to OFF again and then to restart, the gauge will read 0 before the engine starts, then the pressure reads 70. This is with cold oil. Because of the volume of oil in these cars (~9 qts.), it takes a while for it to warm up and reach operating temp - maybe 10 miles of driving or so. After the car is warm, the idle pressure in my engine drops down to the 30-40 range on my gauge (about 1/3-1/2 way up the scale), and then goes up to 60-70 when revved up or driving. And my oil temp only goes up maybe to 1/4 the way up the gauge, also takes 10 miles of driving or so to get up to there.
So everything seems to be working as it should and I never really noticed that before, that it takes so long to get the oil up to temp.

That pressure at Idle and rev seems to track what I see on my 92.