[Dan-MI]

I've got a couple problems with the oil pressure gauge. One is with the idiot light coming on sporadically after the car has run awhile. Searching through the old threads, I found some ideas to check. The oil release valve sticking sounds like a good starting point. However, the actual needle part of the gauge never moves up or down. It is at zero when the car is off, but as soon as you turn the key on the gauge goes to 4 and never moves. Even with the engine off. The wiring appears fine. Anyone with any ideas on where to trouble shoot? If I can avoid it, I'd rather not just start replace wires, sending units, or the gauge until I hit upon the problem.

 

[baronbors]

It is at zero when the car is off, but as soon as you turn the key on the gauge goes to 4 and never moves. Even with the engine off. The wiring appears fine. Anyone with any ideas on where to trouble shoot? If I can avoid it, I'd rather not just start replace wires, sending units, or the gauge until I hit upon the problem.

Let me see if I have this right? From your description the gauge is at zero. Turn on the ignition and it goes up to 4 and stays there. Turn off the engine and it stays at 4. But when you go back and start it later it is at zero again?
Easiest thing to do is get a replacement gauge that works (BTW- I have a spare one) disconnect the sending unit wires and temporarily hook it up with a set of new wires (make sure you also gound the gauge to the frame). That would eliminate the sending unit if it works OK. Then I would check to make sure the wiring hasn't shorted out with a vom meter. That would eliminate the wiring. Only thing left is the gauge. Replace the gauge with the original wiring if OK and bet it works. BTW- my bet is you have a bad gauge .

 

[Matt M240Z]

ok, please help people, i too hav a severe gauge problem. Only one of the filaments in the right brake light was burning after i reattached the wires (after i painted the back of the car), so i tried switching the wires. First i just switched the side wires with each other. Then, i put the ground wire on the side and both filaments lit up. Then after that, my friend tried to stick the key in the wrong way in the ignition, and after that my gauges have read lower than wut they are supposed to and they just shut off wen i hit the brakes. Now when i turn the key to on, the battery and oil pressure lights dont come on. The car is currently under the garage with one battery wire disconected.

 

[guyopel]

guyopel

this sounds like a poor ground ( loose or not clean at contact area )
check grounds with voltmeter;;
hope this helps

 

[baronbors]

this sounds like a poor ground ( loose or not clean at contact area )
check grounds with voltmeter;;
hope this helps

Agree

 

[GTJIM (R.I.P.)]

Search!

Put "Oil Gauge" in the search and look for the thread discussing "oil pressure gauge does not work properly ( blah was 1.2N blah )" and also "OP Gauge / Sender Basics".
Both real informative threads - I have just printed them and placed them in my Indespensible Info File.
They have lots of info on the pressure sender and what happens when it is hooked up electrically back to front. Sounds like your symptoms.

 

[Matt M240Z]

hey guyopel and baron, so ur sayin that even a bad ground connection on the tail light housing could make the gauges in the dash innacurate? Why would the tail light wires effect them? It does make sense though sense anytime i hit the brakes, the gauges shut down

 

[guyopel]

guyopel

a poor or open ground can cause a backup in ele.sys, to hunt for a
ground in other parts of the ele. sys. .. & is evident in other sys.
droping out or other changes ..

hope this helps