Good News for Low Oil Pressure

Over the summer it seemed as if my 4.0 was dying It as 147K on the clock...Oil Press on the freeway was just shy of 40 PSI. and on more than one occaiton it would drop below 10 PSI for a few moments .... Normally on exit ramps and parking lots where it was at idle and at temperture.

I now had the time and money to start working on it. A New pressure sensor which is literally a 5 minute job put everything back in line. Where it would drop below 10 now stays well above 20 PSI... Where it was barely 40 PSI now is above 50 PSI.

I did the pressure sensor first because while I had no other symtems and noises of low oil pressure. And it feels good to know that it was not a serious issue. I always had good power and never had the noise that comes when an engine is about to let go.

Common sense is so uncommon. :laugh3:

What is involved with replacing the pressure sensor?

My gauge is fubared until the Jeep warms up. Shows over 80 PSI when cold....and that's impossible. Jumps around occasionally too.

Blaine B. said:

What is involved with replacing the pressure sensor?

My gauge is fubared until the Jeep warms up. Shows over 80 PSI when cold....and that's impossible. Jumps around occasionally too.

Click to expand...

un-hook the wire, Screw out the old one and screw in the new one hook up the wire. It is located on the '97 just above the oil filter.



Jeff

Ah, I know what you're talking about. I see the wire, it runs the length of the engine to the front.....in corrugated loom and through wire slots.....I can't seem to see where it plugs into though.....lol.

I'll see what happens with it, it isn't a really big deal as long as the engine runs right.

i had the same problem last month... took it to the dealership because i was tired of hearing "your engine is shot" and "try this". they changed the sensor and it ran fine. no more check engine light or check gauges. but now the check engine light is back and it says outboard computer. so i think maybe the computer has been going bad and possibly that is what caused the sensor to read bad. maybe not. i dont know.

Blaine B. said:

What is involved with replacing the pressure sensor?

My gauge is fubared until the Jeep warms up. Shows over 80 PSI when cold....and that's impossible. Jumps around occasionally too.

Click to expand...

Actually it is possible, I had the same problem >80 PSI on the oil pressure gauge. It was a clogged Catalytic converter backing up the engine exhaust that was raising the gauge pressure. After replacing the Cat converter it read 40 PSI.:roll:

That I would have to see to believe.

I'm with old_man. 80psi isn't unbelievable if you run heavy oil, but a clogged cat isn't going to raise your oil pressure.

Um I did mention once everything is warmed up, it does show a normal reading.....

Now a cat wouldn't only be clogged when cold, would it?

In my case it started out as a loose honeycomb that rattled. Oil pressure was fine. Then suddenly it stopped rattling, the engine lost power when you gave it gas, or tried to die, stumbled, shook, and the oil pressure gauge was peged at >80 psi. We replaced the cat converter and all was well, ran fine, oil pressure read 40 psi and no more worries! It was a big surprise to me too.

Your comment about it (the pressure) jumping around made me think of when the cat honeycomb was loose and rattling around in mine just before it lodged somewhere and pluged up the works and thus raising the oil pressure reading on my gauge.

Keep in mind one side of the gauge is reading atmospheric pressure. The oil gauge is not reading absolute pressure, it is reading the difference between the oil pressure at the pump outlet versus atmospheric pressure.

Mike MccGinness
So. Houston, TX

My cat is solid if I beat on it, no rattling ever.....I've been in one vehicle with a rattling cat (96 Cherokee owned by a friend of mine)