Sorry for asking here a totally OT make - but you guys are very very smart fellers and I figure I'll get better response from you than find some yeep forum (when I don't even own one).

A friend has a '93 Wrangler, they bought it fairly recently through a dealer.

Noticed a slight burnt oil smell the other night and today when arriving at work noticed the pressure is pegged on high. I advised to cancel all evening plans and not to drive it anywhere but the closest shop / lube place.

Diagnostics so far:
Pressure is pegged high after about 2 seconds and stays high for quite a while after shutting down.
Letting the vehicle sit for hours, when you first get back in, the pressure gauge is down to low.

No clue on vehicle history as I said it went through dealer.

They are running to a shop (3 blocks away) for an oil change and detergent add (i.e. seafoam if possible). Two possibilities that came to mind are clogged filter and clogged galley - really hoping the filter cause how do you fix other issues short emptying the checkbook.

Am I steering in the right direction here, any other causes I am not considering?

 

Broken gauge or sender. What does it read when the key is off?

When you hear hoof-beats, think horse, not zebra...

 

Key off, immediately after shut down it is pegged at high.
Key off, after sitting for an hour and it is pegged at low.

Yesterday (and up till now) middle of Normal during run (any rpm).
Today pegged at high during run (any rpm).

 

is it a 4.o litre? those send units tend to do this nonsence every now and then. before spending any money, remove sender and hook up a mechanical unit. you will know right away.

 

Parts Jeep w/4.0L I got had the oil shoot up through the valve cover tube to the air intake box. Remove that tube and see what happens. I don't mean letting it run forever either. Just a while to see if a lot of oil shoots up through the hole. If that's the case, then you have a possible blowby issue. There is no PVC on the 4.0L, it all goes back into the air box.

Let me rephrase that, that is if the sending unit checks ok. Point being, if the sending unit is good, there is a reason the oil pressure is building up, and the result will be a blowby, IE blown rings or a hole in the piston.

 

Just to close this thread out and provide the answer.

The sending unit was the issue - as suggested here the jeep has a history of sending units going wonky, mechanic expected that and confirmed. Being the only vehicle for this person they had the shop where they took it go ahead and do the sending unit replacement ($45 for the unit, $20 for an early oil change, $50 for the labor).

Thanks much to all for the feedback and suggestions. It's good to know I got you guys in a pinch.