Could this just be the sending unit? I was not the owner of the vehicle when this happened but the gauge has always been pegged all the way to the right never moves I just wanna know if I can fix it without replacing the cluster because the vehicle has only 100k miles

 

Try unplugging the wire from the sender on the engine by the oil filter and see if the gauge drops down to zero when you turn the ignition on. If it does then the sender is dead.

 

nada it moved a little bit for the first time I believe but not to zero

 

Just replaced my sensor today to solve my problem. With the sensor unplugged the needle moves to the high side like yours shows. If you ground the sensor wire (run a wire to ground from your sensor connector) and the needle moves all the way to the left or zero, then the gauge is okay and your sensor is bad.

 

Based on the above, you may have open circuit between the gauge and the sensor. If your gauge goes downscale (zero) when you ground the wire at the sensor then you have a bad sensor. If it doesn't move then check the sensor wire for voltage. If it is zero volts when measured to ground then you may have a bad wire. I doubt you have a bad gauge.

 

Maybe I wasn't clear. With the bad sensor it went to zero after grounding like you said. With new sensor gauge works perfectly.

 

After reading the description of how the gauge/sender works you are right, straight to ground should show no oil pressure. I thought it was the other way around. So yeah, try grounding the sensor wire as Winterhawk suggested.

 

I've not checked it with the grounding method yet I will just after I post this but its a little confusing trying to figure out what unit I need to buy I'm pretty sure this style on rock auto is the Sender and that this one at AutoZone would but for use in vehicles with idiot lights correct? or do they both complete the same task>?
I cant seem to find one that specify says "sender" locally so if the AutoZone one were to work that would be neat though I do not think it does, I will go take a look at the one that's on there right now but I'm pretty sure its the switch/autozone style and that might be the reason my gauge is not functioning

 

Look on RockAuto for "gage" in the listing. For a 1999, I see
STANDARD MOTOR PRODUCTS PS317
WVE 1S6755

 

You are correct on the 2 types and they work differently. A switch is just On/Off to control a light whereas a sender has variable resistance which the gauge uses to know where to point the needle.
What year is this XJ as I don't think it's a 99 as it's a pre 97 dash and a non airbag steering wheel.

I know pre and post 97 have different senders as they have 2 wires post and 1 wire pre. I'm not sure if Renix era XJ's were different again.

Does your existing wire for the sender have a connector on it or is it just a crimp terminal?

This is what I have on my 95, single wire with connector:
More Information for STANDARD MOTOR PRODUCTS PS257 (rockauto.com)

 

I checked out what the one that's on there looked like and it was the larger unit that I linked on rock auto so I am gonna go with that as I was pretty sure that's the one I need pretty sure that will fix my issue ill post if it does

 

Sounds good

 

oki doki I figured I would let yall know that replacing the sender worked go figure I shoulda known that, but the renix jeep did the exact opposite of my 99 xj when I owned the 99 it went to the low side and the 90 went to the high side thanks for the help also cant believe the advanced auto near me had the sender in stock! 2 minuets and we have a working oil pressure gauge and while I was doing that I unplugged the box that turns on the emissions maintenance light so no more eye sores on my dash at least for the mean time all thats left is to find a sport cluster that works with a speedo cable