My Jeep's 4.0 started to show zero oil pressure at stop lights a few summers ago (157,000 miles) so I thought my sending unit was bad. Changed it. No difference. So I replaced the oil pump. No difference. Then I read on the net to use a Napa Gold oil filter. WTF? I've always used Fram. I tried it anyway and problem solved immediatly. It may not solve your particular problem but keep it in mind. Sounds nuts but it worked for me.
My oil pressure goes from being Ok to almost zero depending on the speed. If i am stopped, it will go low and when driving it will be normal. And i am getting a ticking noise from the lifter area, i think, so i tightened up the rocker arms that were a little under torqued, but didn't do anything about the noise. What should i do next?
I'm very interested in this too, mine is doing the same thing. It goes down to 0 oil pressure at idle and says "check gauges." But it does seem to have semi-low oil pressure at highway speeds too (about 20) so i'm thinking it might be oil pump or sending unit. But i'll try that Napa Gold filter first and hope that makes the difference.
4" Skyjacker Sport Kit
33x10.50-15 Interco M16 on 15x7 stock steel painted black
55w 8k HIDs
My opinion....if you can pull the oil cap from the valve cover, and see/feel oil on the lifters inside, I'd say you're pumping oil to the correct places.
From what I have gathered from the past on other posts, a lower oil pressure is better than a high pressure. And I think, if I'm not mistaken, there is no "warning red" label on the dash panel where the gauge is telling you that you're in danger. (hi or low)
When you see smoke and hear knocks (not ticking), then you might be on to something.
My gauge runs just past 40psi I think, and while stopped, it lowers quite a bit. The engine has 135K on it, and does not burn a drop of oil between changes.
I say....don't worry too much about it.
At some point during jeep ownership, you will BUST A NUT!!!
Ticking could just be a lifter gone bad or it could be a sign of bigger problems to come. I would replace sender (as stated on forum on other threads) and see if pressure is really going to 0 at idle . If you rev motor and oil pressure goes up does ticking go away ? If ticking stays with higher pressure then maybe just a sender and lifter issue. If you have good oil pressure and lifters make noise look into replacing lifters. JMO I am a newb to jeep motors but have built plenty of SBC motors.
I worried with the low oil pressure indication at idle (when engine at operating temp.) and the CHECK ENGINE light for four years. Just last week I had my Jeep in the shop for other reasons and I had them gauge check the oil pressure at various RPMs and change the sending unit, if needed. Oil pressure was fine, sending unit not, new sending unit and oil pressure looks right. I searched this forum and it is a very, very common problem. But.....there isn't much margin for error where oil pressure is concerned. I'd change the sending unit just for the peace of mind.
Never argue with idiots......they will drag you down to their level then beat you with experience.
I have the same ticking noise. I only hear it from cold start up and it comes and goes..once I drive it around and get it warmed up...i can pop the hood and the ticking is gone. I tried some seafoam in it...drove it around for about 300 miles then changed the oil again...still ticks off and on during cold start up. This sound like a bad lifter or dirty one? I was thinking the the oil pump may not be pumping oil fast enough to the head. What do you guys think?
You can lock it..even put a different t/c in it..but its still not a RUBICON!
A ticking noise is not usually an indication of a bad oil pump, like stated above it is most likely just a bad lifter. Just verify the condition of you oil pump by plumbing in a accurate manual gauge to see what the pressure actually is. Factory gauges are nortoriously inaccuarte especially on the early TJ's. My 97 factory gauge would show zero at idle sometimes. I installed a manual gauge and the pressure was actually aroung 15 psi. !