2000 Xj Oil Pressure Issue

[boardmanMJ]

Well recently the motor that came factory in my 00 XJ but the dust. Since I had it up for sale anyway I didn't want to rebuild it or build a stroker motor. Long story short I got my hands on a used 4.0l out of the same year XJ. put the motor in and it runs great...except for one problem. The oil pressure gauge is all types of messed up. It will read 40 pounds then all of a sudden drop down to 0 and check gauges light comes on then come up to right around 20-25. I thought it was the oil pressure switch so I replaced that and it's still acting up. Any ideas?

[88mjgilley]

any breaks in the wiring?

[Backdraft]

don't take this as fact. But I have heard that the connections to the back of the gauges can become troublesome resulting in intermittent screwy problems like that. I have not personally had any expierence with this problem, but it's probably worth checking out.

[boardmanMJ]

don't take this as fact. But I have heard that the connections to the back of the gauges can become troublesome resulting in intermittent screwy problems like that. I have not personally had any expierence with this problem, but it's probably worth checking out.

 

 

any breaks in the wiring?

 

 

As i know of there are no wire breaks or shorts. i broke the clip that hold the connection together but that was after i had replaced the switch with a brand new one so its not in that connection that i broke. i really hate to pull the dash apart in it to see if i wire broke loose or not but i guess thats what I'm going to have to try. I'm thinking about putting some engine honey in it to thicken the oil up so see if maybe the oil pump is starting to go bad.

 

this is what the gauge looks like while I'm driving

 

and as soon as i come to a stop

 

 

 

Josh

[mvusse]

If the check gauges light comes on, the problem is before the signal from the oil pressure sender (should be right next to the oil filter) get to the PCM.

 

But it could also be a defective oil filter. Replace it with a good quality one (Purolater Pur-One, Wix, NAPA) and might change the oil too to see if there's anything in it.

[Geonovast]

Stick a mechanical gauge on it before you start tackling wiring. I wouldn't blame wiring if it started doing this as soon as you put in an unknown used motor. Make sure it's the gauge and that the motor isn't tearing itself apart.

[mountainman]

^^^ this. Borrow a mechanical oil pressure gauge from autozone or your local parts house and do an oil pressure test. And when you do make sure you run the motor for at least 15-20 mins to get "hot" results.

 

Then if its low youre probably looking at a new oil pump and pickup to start. While you have the pan off (IF thats the case) look for metal particles in the bottom of the pan. That will tell you if just your pump took a dump or if you have deeper (bearing) issues.

 

You could have a big sludge island floating in there and its getting stuck up against the pickup.

 

Keep us posted. I wouldnt drive it AT ALL till i had done the oil pressure test.

[boardmanMJ]

this has to be one of the screwiest probelm i ever had with this thing. since i posted up that something was wrong with it the oil pressure gauge seems ok, not perfect, but okay. it hasnt been dropped down to zero anymore and it only seems to drop down to about 30 pounds. unfortunatly i have to drive it every day since the MJ isnt running yet but i have really been babying it (for what its worth) sunday is going to be the day that i fix the oil pressure issue. thanks for all the advice I'm going to get a mechanical gauge then.

 

 

 

Josh