I need to start trouble shooting my oil pressure gauge in my 1984 4Runner. It hasnt worked since I got the truck. I does have power to it, when starting the truck the needle will move from the L position up, but once the truck is started and running it drops and doesnt read. I did replace the sending unit because the threads were bunged up pretty bad and it wasnt tight.
So, when the key is on and the truck isnt running where does the gauge read? I am thinking that the PO may have reversed the plug ins in the back when putting in an aftermarket tach, but kind of want to know that before I tear into the gauge pod.



Thanks!

J

 

Sounds like you have an idiot lite oil sender not a oil pressure sending unit. Hook an ohm meter to sender. Gage if defective is easy to replace. I have used gauge for $10 or sender for $5 plus $5 shipping.

 

I will check the gauge, I know my sender is correct though, just bought a new one because the one it had was bunged up.

 

Is the sender the size of a walnut or a lemon? If it's small it's an idiot lite sender. New the small one is $5-10 and the pressure sender is $35-50.

 

It is the size of a lemon and was closer to $50. The one I took off of it matched it. Gauge has power, so I think I will take the gauge out and check the wiring when I can get some time.

 

Sender wire is the ground leg of the oil lite, oil pressure opens the circuit turning off lite or in the case of the pressure sender moves a rheostat. Ground the sender wire and see if gauge goes to top. If positive power were to contact sender wire it would burn out sender.

 

Great, THANKS! I will check that out too.