Philippe L.

Hi all, I'm having high oil pressure (going over under and over maximum rapidly) at highway speed. Oil level is fine.

92' 4.0 with 275.000 km's.

Any suggestions? Thanks!

superj

sensor is bad, bad connection, bad wire somewhere

Philippe L.

I'll check this out this weekend. I can find the sensor near the oil filter, right?

doublechaz

What pressure at what engine RPM?

BlueRidgeMark

Yep. Not uncommon for the connection to get oil-soaked and cause craziness.

Best thing is to pick up a cheap mechanical gauge to verify the REAL reading, to make sure you aren't chasing a ghost. Most auto stores, twenty bucks. Takes maybe 10 minutes to:

1. Install it with the hose just draped over the engine so the gauge is visible through your windshield.
2. Fire up the motor.
3. Read the pressure.
4. Reverse the process, putting things back to normal.

Philippe L.

I tried making a video of the issue. The oil pressure goes up and down very quickly, it keeps shaking when the issue exists.

This is the video:
https://streamable.com/jkfvse

Philippe L.

Finally had the time to check the oil pressure with a mechanical gauge. (I just bought one online - it goes all the way to 500 PSI, which was a mistake since the measurements aren't that accurate now.)

I noticed the following:

• Oil pressure on idle: barely measureable
• Oil pressure on 2k rev: 35 PSI

So I'm guessing the measurements aren't very accurate.

• Oil pressure on any rev does not go over 5 bar (max on my dashboard gauge)

So it seems like it is the oil pressure sending unit, because with the sending unit oil pressure does max out (in dashboard).

Can anyone confirm this is logic?

Also, the sending unit only has one wire and one connection pin. Is this normal?

PatHenry

Yes - normal to have 1 wire on the sending unit.

+1 on the bad sending unit or wiring issue.

BlueRidgeMark

The wiring is more likely bad than the sending unit. On the other hand, they aren't expensive and it's an easy job.

With a gauge that goes to 500, I would not worry about the readings being accurate.

Philippe L.

The issue really comes forward when the engine is heated up properly. My best bet is the sending unit. I ordered one from Jeep.
Also, the wiring isn't damaged as far as I can see.

Philippe L.

Thanks for the help guys. The sensor is replaced and the issue resolved.