what if oil pressure goes to 0 then everyonce in awhile it goes to about 10 when u accelerate, then the next day it stays at 40 all day, then the next day its back to the weird stuff.. i can be doint 70mph and my oil pressure will all the sudden drop from 40 to 0 and my check gauge light comes on.

 

I'd say replace your sensor as well. "Random operation" is exactly that - random. I've seen oil sensors fail to where they'd read higher pressure at idle than at cruise, believe it or not (no, I didn't cut that one apart to find out why.)

This is why there is a T-tap inline with my oil pressure sensor, with a "dry-break" quick-connect fitting. I back-check my oil pressure gage with a mechanical gage as part of annual inspections anyhow.

 

I have a similar related question:
My oil pressure gauge stays constantly at "60." It never changes under any conditions, ie engine hot, engine cold, RPM high, RPM low. Is that weird?

Also, my temperature gauge never fluctuates and never reads differently. I can't remember where it's "stuck" at the moment, but even early in the morning when it's 25 degrees out, the moment I turn the key, the temp guage reads 200 or 210 or thereabouts.

Any thoughts?

 

my sensor started reading like the OP's and a couple weeks later I was driving home and BOOM white smoke coming out like crazy from my engine compartment, I popped the hood and oil was everywhere I thought my block had cracked, but the oil pressure sensor burst

 

well shoot. That should be an exciting day. Maybe I should put the sensor in my glove box just to wait for the explosion. that would really get a rise out of my wife.

s

 

That can happen as well - the variable resistance gets stuck at a specific value. Replace both sensors.

 

Thanks, I'll give that a shot. Also, I need to edit my previous post; previously I stated that the gauges were stuck at whatever position they were at when I turned the key. This morning I noticed that they were stuck there even with the key removed, so I believe I misstated the problem.

I think your diagnosis still holds, though, so again, thank you!

 

I am dealing with the same issue.

Question: I have a '91 4.0 sitting in my drive. With the same sensor fit my '93? From a search of O'Reillys says no...

Also, the only things that I have done that might be different is I have done 2 oil changes so far. The first was because I just bought this Jeep and who knows when the PO changed. When I changed it, I put in 10W-30 in hopes of lowering the pressure. It worked and the gauged stopped jumping around. When I changed it the first time the oil was full of crud. So I figured on changing it again to get the last of the crud out.

Well it did that today, and used 10W-40. Well, now the sensor is gone funky again...

So, still the sending unit?

Oh, and to make sure I am looking at the right part... Is this it?

Thanks!

 

havensov,
I'm not sure if that is the right part or not. It looks like it, sure, but you need to make sure you get the right one for gauges or idiot light. Also, when I got mine from rock auto, they made me specify which country of manufacture.

Also, while searching rock auto, it appears that the difference between the 91 and 93 sending units is how it plugs into your wiring harness. Check it:
91 sending unit for US model with gauge not light: http://www.rockauto.com/catalog/moreinfo.php?pk=443956
93 sending unit for US model with gauge not light: http://www.rockauto.com/catalog/moreinfo.php?pk=44311

Which one do you have? Hope that helps,
s

FYI, my problem was fixed with the new sending unit.

 

hahaha that's a good one, mine drips oil right onto the exhaust and smells all the time. My oil pressure gauge is also out of control, the damn thing acts like a tachometer. When I accelerate the the gauge goes crazy, it even goes beyond 80 or whatever the max is.

 

Mine did the same, until I got a new oil pressure ending unit. Maybe some people think replacing it will take away part of their Jeep's personality or something. Personally, I found it distracting and I don't like not knowing (or having a very rough estimate) what my pressure is. Either way, it would probably be an important and cheap repair for anyone foolish enough to try to sell their jeep in the future.

s

 

By chance, does anyone know where to find the sending unit on a V8 engine??? I don't see one above the oil filter at all.

 

I am having the same problem. mine is a little different tho. I had my oil sensor replaced and it still bounces all around from 0 to 65, depends on the time of day ect. My engine sounds good no knocking but im so confused and what would be causing it. would synthetic oil be the issue? just change my oil a few days ago

 

Testing and InspectionTurn ignition switch to Run position, then disconnect oil pressure sender connector terminal S. Indicator needle should move to H side of gauge.

1. Touch oil pressure sender connector terminal S to ground. If indicator needle moves to L side of gauge, replace sender. If not, repair open circuit to gauge.