Oil pressure gauge-- always shows pressure!

[Skunkworks Challenger]

My oil pressure gauge shows 40 psi anytime the key is on, engine running or not.  The car is a 70 Challenger with the rally dash and the gauge is electronic.  If I unplug the lead from the sending unit it reads zero but if I plug it back in it reads 40 psi.  I have tried three different sending units with no change.  All the other gauges in that cluster seem to work fine so I doubt if the problem is the voltage limiter.  Any suggestions?  PK

[Chryco Psycho]

weird , does the guage peg when you ground the wire . to me it seems to be a sending unit problem where it is making a ground through the unit somhow

[Skunkworks Challenger]

Hi Neil, thanks for the reply.  Yes the gauge pegs if I ground it to the frame.  One of the sending units was on the car before and worked.  The second is off another engine. The third is new out of the box.  I'll try a fourth one before I get too crazy.  I know I have oil pressure because my lifters are quiet.  PK

[BIGSHCLUNK]

I have a similar problem, but only once i'm running max oil pressure on the gauge all the time. Switched senders no difference. Let me know what you find ..thanks.

[Strawdawg]

and you are using the sender that is indicated for the electronic gauge?

[Chryco Psycho]

the factory guage is only good to 80 psi , many of the rebuilt engines I have seen push close to 105 cold & 80 Warm so the guage would be pegged & reading accurately