Oil Pressure Gauge Pegged Out...........

[Wild Comanche]

I have a 1989 Jeep Comanche.  Just today I noticed the Oil Pressure Gauge was pegged out to the far right,  with the engine idling and also at speed.  After shutting down the engine the needle was still maxed out to the right.  It seemed to me that the needle always returned to zero with the engine off.  This is the first time that I have noticed this problem in all the years I have owned this vehicle.  Possibly a faulty gauge?  Or a broken wire or loose connection?  It doesn't seem likely the sending unit just went out.  But I don't know. Any help on this matter will be appreciated.  Thanks..........

[Eagle]

Could well be a broken wire. Test procedure:

 

Disconnect the wire from the oil pressure sender. Turn on the ignition (you can start the engine, but you don't have to. But the ignition has to be in the RUN position, not the Accessory position.

 

• With the wire disconnected and not touching anything, the needle should be pegged at the high and of the scale.
  
• Touch the wire to a good ground (like a clean spot on the engine block. The needle should swing to zero.
  
  

 

If the needle doesn't read zero when the wire is grounded, you have an open connection between the sender and the gauge.

[ParadiseMJ]

...or the sender is shot.  I've replaced one on each of my Renix Jeeps with the same problem...$15

[Wild Comanche]

Thanks for the tips.  After posting this problem, I checked the internet and found that the sending units are a common  problem..............

[Wild Comanche]

Well, figured out the problem.  The male terminal on the oil pressure sending unit/switch had completely broken off.  Looked like it had been really twisted.  Since I do most of the wrenching on this vehicle, I will have to chalk that up to operator error.  I changed the oil filter 2 weeks ago.  Somehow I must have hit the connection.  And it finally completely broke off.  Thanks for the input..................

[Eagle]

Easier to fix than an oil pump ...