1991Jeep_Man

I'm starting to fight a low pressure issue with my '91 XJ. She has 205K miles, almost 206K. I didn't have any issues before I put a bottle of Lucas in it, and now Im startin to wonder. Anyway, my oil pressure is now at 17-19 psi hot idle and then at 2000 rpm I have just a tad over 35 psi. After that, it barely goes up with engine RPM. I replaced my sending unit with a Duralast from Autozone yesterday because the dealer seems to only have a listing for the $12 dummy light sensor, but I am still having doubts. I've heard of A/Z sensors disagreeing with the XJ, plus the XJ gauges aren't very accurate to begin with. So...

I have considered replacing my oil pressure gauge by disconnecting the old one, cutting out the gauge from the cluster, and replacing it with a mechanical gauge that mounts in the same hole. Then eventually I'd do the same with the temp gauge except keep it electronic, volt gauge, and gas.

Also, does this sound like a bad oil pump? I've been told bearings are possible, but the engine has NEVER been starved of oil and I have no knock. Thanks for any help/ideas!

freegdr

try changun the filter its a cheap try mine had probs last week and i change the filter its worth a shot

93gc40

Sounds like you need to check your oil presure. Using a machanical gauge. You need to determine if you have a OP problem or a sender issue or a gauge issue. Start by testing the oil presure. the gauge in you dash IS an idiot light with a movable pointer instead of a light bulb, even if you upgrade it. A mechanical gauge in the dash would require running an oil line into the dash.

1991Jeep_Man

So, I am thinking a new oil pump is the last route, plus I can go ahead and replace the RMS as well as check for play in the con rods (and praying to God the low OP isnt due to toasted cam bearings). I am also still liking the idea of a mechanical oil pressure gauge because it's live-time and much more accurate than the factory electric.

So, which oil pump from NAPA? High volume or standard flow?

The Rooster

i would put a mechincal guage on it 1st.... to see the real oil pressure is at.... you can add it with out cutting out your old one...

1991Jeep_Man

Is there like an T connector or something I can use where the OPSU goes? I was thinking, since running oil to the cabin can be messy, etc, maybe instead have both the factory gauge and mechanical gauge mounted AND functional, but have the mechanical gauge mounted in the engine bay.. So basically if I am concerned, just pop the hood and take a look. No need to risk burning a hand to swap the fittings. Main concern: would this t-fitting cause a differentiation in the oil pressure?

BRUNER247

A little copper line running through the dash is simple. There won't be no mess from oil. The little compression fittings won't leak. Running the mechanical oil line is as easy as running a wire through the firewall.

1991Jeep_Man

I still think I wanna run the mechanical one through the engine bay; basically because later down the road I want to invest in a nice gauge set, and want to keep the electrical gauge with the set. But would some kind of t-connector be feasible? Also, should I go with the high volume pump or the standard one?

1991Jeep_Man

Also, I was lookin at a rear main seal at Autozone, and the description for the item said "double lip; improved design". Any ideas on what this means? Usually when I buy a part from anywhere that says improved design, it leads to a crap out.

freegdr

myself i trynot to buy part that take alot of time to install from autozone/advanced parts store stick with napa or bennett type auto part for the important stuff

1991Jeep_Man

Alright, so I've got the oil pump (I opted for standard flow) out in the Jeep as well as an oil pan gasket and rear main seal waiting to arrive. I just have a few questions about this swap:

1) About how long of a job am I looking at? The only time I have is Sunday morning.

2) General process? Anyone know a good write-up?

3) How do I prime the oil pump? I heard to pack it full of vasaline.

4) Any other tips?

Thanks for all the help!

freegdr

its gonna take a few hours the higher you lift is the easier when i didmine i was on 6.5 inch of lift was pretty quick this manual may telll the how of it just remember you oil pump does not create oil pressure just flow http://www.filestube.com/537d2723635...ual-84-93.html

freegdr

i really dont think your oil pressure is bad mines a little higher but ive got like 70,000 less miles on mine watch thic vid bearing might be more what you need napa sells them if needed but it aint a morning job..https://www.cherokeeforum.com/f51/ho...e-works-82130/

1991Jeep_Man

I'm also thinking of picking up some rod bearings. Idk, I hooked up a manual pressure gauge this morning, and with a semi-warm engine (only about 1 1/2 hrs allowed to cool in the rain after parking), the oil pressure was about 40 psi at idle. But then, after about 2 minutes of slight reving, it dripped to about 35 psi, and when I would rev the engine briefly, it barely went up. As it stands, the lowest my pressure has gotten was 35-37 while going down interstate, and about 18 at idle. These just seem low to me. Could this also be a clogged pick-up screen?

freegdr

http://www.ehow.com/how-does_4778942...-cherokee.html