I have a 85 gsl-se with a brand new Mazda oil pressure sending unit. I installed this new unit, hooked up the wire and nothing. My next move was to peg the unit and it worked like a charm. I ground the pressure senor wire to the body of the car and the gauge would max it's self out.

So can someone explain to me what the heck is going on?

I have no idea what else to do? Suggestions?

Anyone know how to wire a resistor into the system so I can check my gauge? Any kind of help with this would be great.

 

I spent a couple of hours yesterday playing around and here is what I found out:

1. I confirmed that the oil pressure sending unit works. I used a syringe, tubing and multi meter and measured resistance.
2. The dash gauge only pegs when grounded to negative end of battery. The gauge doesn't peg when grounded to the body of the car.
3. I also confirmed that the wire from sending unit to the first alligator clip has not cuts and is in working order.

I'm begging to think that the gauge is the problem. How do I confirm?

 

Possible grounding issue with engine block to chassis/batt?

Did you use any pipe dope or Teflon tape, if ya did it might be preventing sender from grounding.


My $.02