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97 wrangler oil pressure...

I have seen a lot of posts here about oil pressure senders failing on 97's, but I want to just see if this fits the profile..

My sons wrangler, 4cyl, suddenly started showing about 20 lbs pressure at idle. The pressure swings with engine speed, to about 45-50 lbs at highway speeds (1500 to 2500 rpm) and will drop quickly again at idle to 20-30 lbs.. Even though the manual states this is ok, it has never changed this much before. (usually stays over 40lbs even at idle when hot.) This was sudden. No change in the sound of the engine. Changed oil several weeks ago, and it is still up to 'full'. My grand cherokee's sender went out last winter (also a 97), but it behaved very differently (the pressure would just randomly drop and rise..) I plan to replace the sender as soon as I can get one, but I ask if anyone has any other ideas...

cal

Reply to
Cal
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Sounds pretty normal once it is warmed up completely. I'd expect the idle pressure to start off higher then decrese to to 20 psi or so. I did have to swap out an oil pump last summer because the highway pressure dropped 10-15 PSI during the course of a 200 mile trip (verified with a mechanical guage) but the pressure (hot) should pretty much track the RPM with no rapid changes at any particular RPM. Mine does drop a bit lower with really high OAT on a long, sustained run but even I get a tad limp when the air temp pushes 100 F.

Reply to
Will Honea

I was out on a trail with my '97 TJ and as I was sitting idling all of a sudden mine dropped to almost nothing and the 'check gauges' light came on. I rev'd it a couple times and it went back to almost normal and when I finally got back to pavement it was pretty much business as usual. It has never happened again either. I wonder what happened in my case? Something momentarily obstructed the pickup tube or the pump got something stuck in it?

Shawn

Reply to
Endo

Reply to
Will Honea

It was at crawling at idle on mostly level ground from what I remember. Can't think of anything external that could have caused it. Wonder if it was a symptom of faulty contacts on the back of my instrument cluster? I've had the turn signal indicators go out a few times. It did light the 'check gauges' light though. Not sure if that is computer controlled or built in to the cluster.

Shawn

Reply to
Endo

That's EXACTLY what my '97 4.0L was doing; it was the OP sender!

-jeff

Reply to
Handywired

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