Ok this does not look good to me! At first start up when its cold its about 35-40psi at idle. Driving around for about 10-15 minutes it drops to 20psi at idle. Now about 30 minutes later when its warm this is what it gets to sometimes when im at idle!!! Now of course when i give it gas and drive it around it goes up as my RPM's go up. BUT, when at idle its just at the redline. Sometimes it get down to the bottom redline and the "check guages" light comes on so i have to get it some gas. What could be causing this? Im in the process of rebuilding an engine but i dont want my car to take a crap on me. What are your guys opinions on whats happening?

 

your oil pump is taking a crap. replace it quickly or pay consequences of an oil starved engine. oil pump should be relatively cheap and if you know what your doing, changing it should only take a few hours.

 

first thing to do is to verify with a mechanical gauge

 

If you are super lucky its the sender unit or the gage.
If your just lucky its the oil pump.
If its worn bearings and excess clearances then you aint so lucky.

 

Also common for the oil pick-up to fall into the oil pan. Bang on the bottom of your oil pan and listen for a metal piece bouncing around.

 

I've heard this diagnostic before and have always wondered how people come to this conclusion. I mean, what exactly would have failed in the pump? It's the most lubricated part in the whole engine after all. About the only thing I could think of would be the pressure relief valve sticking. I hate to say it, but if that pressure is legit, you probably have worn main bearings.
Scott

 

Does the engine get noisey when the oil pressure lamp comes on? If no, good chance its a sender/guage issue. If yes, start planning to tear it apart.

 

how would check it using a mechanical guage? The engine has been running strong but does have 207K miles on the clock. I need to find something to fix it because i dont want to tear it down and put in a new pump when about 2 months i should have a new motor going in. In the mean time, THIS IS my daily driver so i want it to last as long as i can. It's been doing this now for over a month.

So worse case if its the main bearings, then the motor is just about done?
I've been putting in 20w oil and lucas additive to thicken up the oil but still no help

 

my 97z started doing this and shortly there after the motor grenaded. it only had 112,xxx miles on it and i babied it for its whole life.

 

the motor really doesnt get that noisy. I was sitting at the drive through for a couple minutes and didnt realize the it was sitting in the red and "check guage" light was on.

I have noticed a couple times at idle that it does shake/vibrate a little (kinda like an engine miss) but the light isnt on. Its just right where its at on the picture above. Im scared to drive it around. Lucky im only 2 miles from work but still want to take it out on weekends

 

A mechanical guage would be attached to a hose with a fitting that would screw into the oil pressure port. Removal of the oil sending unit would be necessary to access the port. For best results a guage with 1psi increments is recommended.

 

I had the same problem right after I got my 95 Z28. Had only 58k on it. Number 7 rod broke in 2 places on the freeway after about 2 hrs at 75mph.

Oh well, all forged, no more worries.

 

Mechanical guage will tell you all you need to know. You did not mention if this problem occured over night or if it is the product of a slow decline in oil pressure. 207K on the clock my money is on rod and main bearing wear.

 

the oil pump is just two metal gears that are compressing oil into a path in the block. over time the metal gears lose the tight fit they have and the compression is lost therfore losing oil pressure.

 

What wt oil are you using? Switch to a heavier viscosity and see if it makes a difference. This is the first thing you should do----bearing in mind that you shouldn't even start an engine with excessively low oil pressure unless you are prepared to rebuild.JMHO