I know the horse is dead and I am still beating it. I've used the search option here, google, different sites, prayed, drank heavily, nothing.

1999 XJ 146xxx miles
Cleaned carpet seats, interior, put back in, fired it up, oil pressure dropped.
I change the oil once I noticed, same.

I have recently done
Valve cover gasket
Oil pressure sending unit (after research)
I changed the oil with a full synthetic 10w-30 and a FRAM filter after i initially saw the pressure drop. I have heard horror stories about fram filters.

No one in my local area has a Oil Pressure Test kit in my immediate area.
I'm convoying out tomorrow to get one.

Just so we are on the same page, no noises from motor, no ticking, valve cover was relatively cleaned when I replaced the gasket. Pressure was aound 5ish on cold start up today, yesterday was 20, you throttle it and it spikes but soon drops.
I would agree on some bottom end work but it runs way to quietly and good.
Any and all help would be greatly appreciated

 

put a mechanical gage on it.

 

+1 on mechanical gauge.
Learned the difficult way on this one myself..

 

I tested my sender when my gauge started reading 0. I found online somewhere if you unplug it your gauge should go to max and if you connect both sides of the plug from the harness it should read zero. Couldn't get mine to work at all even with a new sender. Leads me to believe I have a short somewhere in the harness. One time it went up for a bit then back to zero not sure how but that's it. I need to get a mechanical gauge or tear the harness part and find where it's shorted. Just figured if I lost oil pressure I would know it and wouldn't need a gauge. After all some Cherokees only have a light.

 

Both the senders and the gauges tend to go.
And as you stated wiring could be a issue.

 

Going to get a mechanical gauge today, ill find out what my pressure should be at elsewhere.
Thanks for the fast replies everybody, Ill update post after I find out what the mechanical gauge reads at!

 

That is low mileage on your engine, did you have decent pressures before you changed oil/filter, and was it your first oil change since purchase?

 

So this is how it went.
Replaced valve cover gasket, alternator, serp belt, water pump, thermostat. Pulled interior out, cleaned put back together, still havent change oil since I bough it but has ran alot with no issues.... temps, oil pressure has been fine
Started it after i put the interior back in and oil pressure dropped.
Did research and put a new oil sending unit in, change oil at the same time. Still low to no pressure. Some cold starts its normal but quickly drops.
I did use a FRAM oil filter.
I just bought a pressure tester kit so we will have some definitive answers here shortly, will update!

 

UPDATE
The 7/8 Brass fitting that my Oil pressure sending unit threads too was hand loose. I tightened it down, put mechanical gauge on and is at temp and is holding around 50 psi at idle.
I held it at 4k RPM and it held at round 60psi, let off and dropped back down to 50 PSI.
I am using a 10w-30 full synthetic, with a fram filter FYI. 50 PSI seems to steep for idle?

 

UPDATE
Sorry to blow up this thread
Drove it around with the mechanical gauge hooked up.
Now Idling at 30 psi, i throttle it, it jumps to 40+ in park.
The lowest it got was to 20 psi while driving, i gassed it, slowed down real fast with no throttle, hit 20 psi and proceeded to come right back to 30 psi

 

Sounds like you should drive it.

 

ON IT madmanmarty !

 

And if you haven't done it yet, get rid of that Fram filter...


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