Weird oil pressure needle indication

Hi listers

At iddle the needle waves in the middle of the gauge, but when RPM goes 1000tr/mn and up, the needle stucks after the maximum index.
Bad Sensor ?

Thx.

Christophe Salvaing

I suppose you are talking about the '91 you bought recently...
I wonder if this problem is not related to same causes as the one you have with the low fuel light?..because on that model, (at least on the '93 diagram), there is no actual pressure measurement, just a switch that activates the needle in the same (opposite) way as a low pressure alarm light..and consequently this would indicate some fault in the instrument panel, cause the oil pressure switch only has 2 positions: OFF and ON... (may be a bad ground... speculation!!..)
See diagram: 3.1 is VIN D : www.avigex.ca/xport/instrumentpanel1.jpg
If it did have a real pressure sender in '91 (as it was the only engine available then, may be they were more generous) , then I agree the sender would be the culprit, plus the fact it happens only at 1000 rpm...

I know in the 95 3.8 if the ground wire form the starter to the frame is cut..the needle on the oil pressure starts acting erradically jumping up and down,also the a/c stops working too....

My 93 tsport would be maxed out all the time. Replaced gauge and still the same. Found the ground wire at the sensor and ran it to a good ground and it now works. Not sure on 91 's though.

I have the same problem, the needle keeps waving at the middle and sometimes just rockets to the max and sticks there. I would check the ground on the oil sensor, but this being my 1st car and me being a noob I have no idea where it is located. Is it close to the pan?

It is the 93 3,8

Thanks for the help

my oil sender is located in between the belt down low. If you look at the passenger side of the engine you can almost NOT see it. You have to get a light and sometimes a small mirror and then it is hard to see. You have to get your head right down in there and then you will see it.

It will have a plug in connection that pulls off. Usually they are so greasy and black you are not sure if it is there.

Not too easy to get off but I had to use a vise grip and work at it. They just screw in.