King Nothing

iTrader: (9)

This is what is happening, the engine oil pressure stays around 40psi at idle at operating temp with easy driving, at 2000rpms at OT with driving easy it doesn't go past 45psi. When I give the throttle more pressure for more fun take offs or even just want to get up to speed faster, I notice when I come to a stop at idle right away my psi is fluctuating between 20-25. I know the spec for oil pressure is 7psi for every 1000rpm, so 20-25 is ok if it's not fluctuating. My question is regarding the sudden drop of oil pressure and the fact that it's fluctuating. And yes the oil has been changed and I'm not running a Fram oil filter which comes up in the threads I've searched but I couldn't find one with someone asking this exact problem. I have a good guess what the culpritis, but I'd like to hear some other opinions. And how long this has been going on, I don't know because the engine was installed from another Camaro.

RPM WS6

iTrader: (3)

I would suspect the sending unit first, as they often seem to be problematic.

King Nothing

iTrader: (9)

All the years I've been on here, why is this the first I'm hearing of the sending units going bad lol well a sending unti is easier to check compared to bearings or a lifter.

RPM WS6

iTrader: (3)

I wouldn't jump to suspect any internal engine issue unless you're having some other problem (such as noises above and beyond what is "normal/typical" for an LS1.) Oil pressure sending units do fail in this way (needle shake, erratic readings, low reading, etc.) on these cars.

You could also send an oil sample in for analysis, if you are concerned about bearings or other abnormal internal wear. Lifters would not even enter my mind unless there was significant noise (which you didn't mention.)

King Nothing

iTrader: (9)

I forgot to mention I do have a ticking on the driver side, I'll drive it today and see if it gets louder with acceleration, but I don't believe it does.

wssix99

iTrader: (5)

You've missed a number of threads, then. I've been a victim of this and can attest that the sensor is also a major PITA to replace: https://ls1tech.com/forums/general-m...ding-unit.html

This is worth reading up on as many people (including myself) have had major issues with aftermarket sensors. (The off brand wasn't much better than the bad stock sensor...) It appears that this is one of those situations where it pays to get a GM part.

kingtal0n

iTrader: (1)

did you see the thread where the O-ring is pinched and the oil pressure more or less hovers around 40psi instead of 65+ like it should when the engine was revved?

King Nothing

iTrader: (9)

I had to replace that sensor years ago when I broke it when I had the intake off . . . can't remember what I was doing to break it lol I want to clean up the top end of dirt, I'll pull the manifold off and test the sensor.
I did and it completely slipped my mind, I'm gonna go tinker in the garage and I'll rev it up and see what it does after I top the oil off.

RPM WS6

iTrader: (3)

In reviewing several old threads about this, it seems that erratic and low readings at idle is a pretty common problem for these gauges. I've seen this with some of mine from time to time as well. Sometimes a new (even GM) OPSU doesn't cure it. There are theories about it being an issue with the gauge itself, wiring, etc. The scenario seems to always be the same - odd idle behavior, including low readings and/or shaky/jumpy needle but only after the engine is hot, and then normal behavior as soon as rpms are brought above idle speed. No issues on a cold start or really at all until the engine is plenty hot. Doesn't look like anyone has found a solid answer for this, but many people are living with this issue for 10s of thousands of miles/years without having any engine problems so I think the issue is more electrical than mechanical. Many with this problem have also hooked up mechanical gauges and found that pressure is normal, even though their stock gauge is jumpy at idle.

King Nothing

iTrader: (9)

I'll check everything and I'll check with a mechanical gauge to see what it's at.

kingtal0n

iTrader: (1)

Yes you really need a mech. gauge for accurate diagnosis.

I've seen electric gauges that read some oil pressure even when the engine was off!

Craigtom86

iTrader: (3)

I agree with the gauges being a possible culprit. Gm clusters are known for stepper motor failures. A mechanical gauge would be best but a quicker, simpler solution would be to use pretty much any diagnostic scan tool to read the oil pressure. If the scanner reads steady it's obviously the gauges. If not, it's the sending unit or worst case and internal failure somewhere. Of course the scanner will not tell you anything if the sending unit is bad but I figure it's worth a shot to rule out the gauges since it's so quick and easy.

King Nothing

iTrader: (9)

True true

RPM WS6

iTrader: (3)

I agree with this as well. There are just too many complaints of this exact type of odd oil pressure gauge behavior to really put much faith in it being a mechanical/engine issue. I've seen some of this odd behavior on some of mine as well and I don't really worry about it.

King Nothing

iTrader: (9)

But I could understand if it does this every now and then, but it only happens after I punch it. That's why I don't suspect the gauge, it'll be hooked up to the scanner on Friday hopefully and we'll look at the readings.

RPM WS6

iTrader: (3)

When mine have done this, it's always been after everything gets good and hot, but then goes away once the engine cools again. Oil pressure is obviously going to be higher when cold, but if an internal issue had occurred that caused erratic and suddenly low readings at operating temp I would expect to see at least *some* difference in the cold/warm-up readings as well. However you did mention some engine noise - LS1s aren't particularly quiet engines but if the noise is new or alarmingly loud then perhaps there is more cause for concern.

Craigtom86

iTrader: (3)

I agree that the pressure being erratic after high rpms is odd and doesn't sound as much like failed stepper motors. Does the noise get louder when the oil pressure is lower? I would still hookup to a scanner just to rule it out like you're going to do. Just for fun, next time you see lower oil pressure, shut it off. Then restart it. I've seen the 07+ trucks act like this (VERY common) and the sending unit or the sending unit screen (filter) is typically the culprit. Under higher pressure they get crap in them partially plugging it sending crazy readings to the gauge. Once the oil pressure is gone the crap tends to clears out and your oil pressure will read normal again.

RPM WS6

iTrader: (3)

I wonder if it's actually due to high rpms, or if it's just that the lower pressure which always results from hotter oil (due to said higher rpms) puts the gauge in a range where it then becomes erratic (until the oil cools a bit, pressure comes up a bit, and the gauge is then back in a range where the erratic behavior doesn't happen)? That's basically been my experience with the odd "shaky/jumpy" needle + lower idle pressure issues on mine. For example, if it's happening when in gear (lower idle rpm for the A4) and then I shift to P/N, which naturally brings the pressure higher due to the jump in idle speed, the shaky/fluctuating needle will usually stop with the slight rise in pressure. I don't see how a 100rpm rise in engine speed (from drive to neutral) could mask any sort of internal engine issue that's serious enough to cause rapid needle fluctuation, so my guess is that something about the sending unit or gauge just becomes erratic within a certain range and/or due to increased temp (of the cluster/wiring, or sending unit, or both.) Then again, I've never had any noises that were specifically associated with, or connected to, the odd needle behavior - so less cause for concern there.

Craigtom86

iTrader: (3)

Makes sense ^^. I guess I'm looking at this as the noise and the pressure fluctuation is unrelated. Lifter tick is pretty common... And coincidence in the automotive field is seen regularly. I'm not sure what scanner is going to be hooked up BUT any bi-directional scan tool can do a gauge sweep. It's a simple test that makes all the gauges go from min to max and back. Anything erratic is failed steppers. Do it a few times and watch them sweep back and forth.

King Nothing

iTrader: (9)

I'll test the pressure sensor if the scanner checks out the same pressure as the gauge. This part will really throw you guys for a loop: after I throttle it some and it gets into the 20's, I can shut it off, let it sit for 10 minutes and start it up . . . the oil pressure is back in the 40's until I throttle it while driving.