oil pressure reading...
 

Hey guys... My girlfriend has had her 82 280ZX for a few months now and we've done a fair amount of work to keep it alive. Its horribly plagued with rust, but she is trying to get as many miles out of it as possible (free car!)...

Anyway, I have a question about the oil pressure reading. I know the car burns and leaks oil a little, but I'm curious to know if these cars are known for having a flaky oil pump, pressure sending unit, or pressure gauge...

Sometimes the reading will fall to 0 at lower RPMs... Also, sometimes you'll be driving and it'll drop, and even go to zero without warning... The engine runs fine, so I know the car has oil, but the gauge will read zero or will bounce back and forth... Possibly a loose connection?

Help me out if you can..

My 78Z is doing the same it is either the sending unit or the connection, or combination of both. As long as you know the oil is fine and the motor isnt running hot or ticking really bad you are good to go.

Seems to be a common problem with the sending unit on Z-cars. Mine reads high at idle, droping to 10# at higher rpm's.

My worry would be if the engine has an automatic shut down when oil pressure is below a critical level. I don't know.

Mine does the same thing. So I replaced the pressure sender and it seemed to fix it for awhile but it seemed like it went back to the same thing, rising at high rpm's and dropping at idle. I tryed a thicker oil and it helped alittle bit more. Then it dropped off agian. So I don't know, I'm stumped to, but it still runs great so i really don't know.
Good Luck
Chris

Chris if your oil pressure is rising as your RPM,s rise that is good. It should go to any where from 50 - 80. At idle it should drop to anywhere from 10 - 30. That is normal because when you are idleing your oil pump isnt pushing that much oil thus lower pressure, the faster you pump the higher the pressure. Now when it is reversing on you and the pressure drops on accleration then you need to start checking thngs.
Shane

Thanks man you cleared up alot of things
chris

at 3,000rpm mines reading 4kg/cm-5kg/cm on the gauge so that works out too be 56-71psi

my engine is not all that old when i got it

If your worried about the drop you should get a manual gauge and check the pressure just to be sure. Any time you have a oil psi gauge doing that you need to find out if its sending unit or an oil pump going bad. It does not take long to damage bearings if you lose psi and by installing manual gauge either temperary or permanent you will know which way to go.............

Very common issue. Disreguard it, or deal with it. An aftermarket guage will also read a lot lower then you'd expect it too.

Mine is begining to show the same thing as well.

I had this same problem. I have an 83 280 zx with the auto shut down. The sending unit was bad and I leaked a minor amount of oil. It finally started shutting my car down while I was driving. I replaced the sending unit and no problem now.
Chris