jbdpayne

Hey guys, been having some issues with my sending unit. I'm in PA, 01 xj, 165k miles, noticed at the beginning of November my oil pressure went to 0. Replaced rhe sending unit with a Napa unit, worked fine for about 2 weeks and then got stuck while driving around 15lbs. I mean id literally turn it on and it wouldnt go past 15 or go Down unless I turned it off. Put a mechanical guage and it was just fine, so Napa gave me a new gauge and all was good until this morning. Turned it on to warm up, read 0, I turned it back off and on again and it's stuck at about 20lbs. Any ideas what the deal is? Maybe the wiring harness itself? I did the gauge function test and it was fine, and I finished my hour commute so it does have pressure, but any ideas are welcome!

robertj

In my experience, the Napa sending unit is crap. Get a Mopar, and you'll be way better off.

PatHenry

I recently did a gauge swap on my 95 (which involved installing an oil sending unit in place of the old switch). I got a BWD (Pep boys and Advance Auto both carry this brand in my area) and it's working pretty well so far.

I think that you can probably rule out the oil sending unit though since you had 3 different ones in there and are getting the same issue recurring every time. If you're sure that the dash gauge is fine, and you're sure the actual oil pressure is fine (and it sounds like it's OK if the mechanical gauge reads ok and you drove it some distance without seizing the engine) then it's got to be an issue with something between the dash gauge and the sender. Probably an issue with the wiring. I'm sure there is someone with more expertise than I on what happens when the wire grounds out, but it sounds like the wire is either grounding out or losing connectivity to the ground.
There was a problem with TJ's in the 00, 01 model year where the gauges would get moisture that would screw with the dash gauge connection. I would check the sending unit connector, make sure everything's kosher there and use some di-electric grease in the connector, then check the dash gauge connector, make sure it's clean and use some di-electric grease when re-connecting that as well.

jbdpayne

Yea honestly I figured Napa would be more on par than AutoZone etc, but I'm shocked it would be more than 2 going bad. Its def not the motor, I drove it another hour fine and after the first went bad I confirmed it of course mechanically, but I got called out today so it'll have to wait till I'm back. I'll check that connection and spray it out/grease it, I can't​​can't imagine anything else other than the wiring harness screwing with it

Ralph77

My sensor started reading way to high in my '00. Guessing it was the original. I too replaced it with a Napa one. Despite how everybody says when it comes to things like this to stick with OEM parts. That was over 3 years ago. No problems so far. ECH OP6185 was the part number. I buy the majority of my parts at Napa. Napa usually has 2 or 3 choices when it comes to parts. Good and better. Good, better, and best. Priced accordingly unfortunately. I always bite the bullet and buy better or best. Pretty sure they make a MPE version of the ECH switch I bought. Which one did you buy?

jbdpayne

I also bought the echlin unit paid 50 bucks, when I get off this job I'll check the connection, might be worth my while to take the cover/tape off from around the harness and check the wiring

Ralph77

I would give it a shot. Still could be defective. Unfortunately it happens.

jbdpayne

It's been a while, but I finally got around to looking at my harness. I cut out the old and wired in a new, none of the wires looked bad, but I did replace it on the fact that the seal didn't look great, and the connectors were worn, I left the Napa unit in, still fires up and only gets about 13psi on the gauge, no more or less with throttle. I then metered the 5v supply, still good at 5.14v. so I'm at a loss here, the cluster test is still fine, I guess at this point I could order a Mopar and love that a try

robertj

Consider yourself lucky, but my Napa sensor leaked like a pig (and not from the threads) a month after I put it in. There's a reason why "everybody" says go OEM.

jbdpayne

I hear you man that sucks. Honestly Napa oem I've never had issues, I know as far as sensors go everyone preaches Mopar of course, or at least the Bosch premium version etc. I just can't believe I would put 2 in, both work for roughly a week and then all of a sudden get stuck on idle pressure. Either way I'll see here in about a week when the Mopar one gets delivered, hopefully it'll clear it all up

PatHenry

I have a bad feeling you're just going to get the same result. Are all the aftermarkets the exact same brand? You could always grab an autozone or advance one, just for giggles and see if it does the same thing.

What I might try is to hit your local junkyard and see if they'll let you pull a gauge cluster and test it to see if you get the same results. This depends obviously on how cool the guys at the JY are (and or their return policy).

It's kind of grasping at straws, but at least you could eliminate the "bad batch of the same brand" and "cluster" possibilities.

jbdpayne

I can definitely try that, I did the cluster test which came back fine but yea something is definitely wrong. I have a good jy here so if this oem one gives me an issue I'll try the cluster swap

PatHenry

I don't know if it's compatible, but if the gauges off a 00 TJ are compatible - worst case scenario I can mail you the cluster out of my old TJ...

RocketMouse

X2 on the BWD unit... their products are worth the price. Put a BWD TPS in mine about 2 months ago. perfect so far. And agree on what to do next there... and using the di-electric grease is definitely a good idea on them.