junkyardjeep

Ok so I recently purchased a 2001 cherokee and when I did the first oil change on it pressure would drop to 0. I replaced the fram filter with a wix filter and problem solved. Well so I thought. No more than 500 miles later it happened again. What do you think the problem could be? If the pressure sensor is bad will it still allow gauge to build pressure when at higher rpm and than drop at idle. Or will it just stay at 0 or fully pegged? If that's not the problem what's next oil pump?

TheJerm

The pressure sensor will do all sorts of weird things as it goes bad.

JeepDeep

The area where the sensor is threaded might be clogged. There was a good thread explaining this not too long ago. I'll see if I can find it. Just take the sensor out and the 90* fitting and see if it's plugged up.

junkyardjeep

i took off the sensor and sensor fitting and they both look clean. no clogs. what i did notice is that oil was passing through the sensor and reaching the electrical plug. i know this cant be good so i guess its time to replace it. what do you think about this?

JeepDeep

Oil doesn't play well with electrical connections. Rent a mechanical gauge to verify the oil pressure.

TheJerm

1st sign the sensor is failing

Bustedback

There is your problem.

tjwalker

There is no confirmed testing based diagnosis yet.

As mentioned, get a "mechanical oil pressure gauge" and temporarily install it where the oil pressure sending unit resides. Then you'll KNOW where you're at, instead of wondering.

Good data = good decisions.

If pressure is poor, then you have a clearance problem with either the engine bearings (most likely) or oil pump. If pressure is good on the mechanical gauge, buy a new sending unit from the Jeep dealer.

junkyardjeep

i think its time for a new sensor since it leaks threw. but like you guys said i need to confirm with mechanical gauge. parts store by me doesn't rent them so gonna have to wait till my buddy comes home to use his. what should my pressure be? and why buy from dealer over regular parts store? im guessing quality?

cruiser54

Here's the link for those of you interested in checking the oil passage:

http://www.jeepforum.com/forum/f19/4...fixed-1304679/

Radi

No less than 10# for every 1000 rpm is a general rule of thumb. IIRC Jeep specs 13# minimum at idle?

You guessed correctly. If that oil pressure sensor fails catastrophically, you'll have your crankcase contents spit onto the road.
Aftermarket parts often feature that legendary Chinese low-bidder quality control...OEM is usually built to a higher standard.

cruiser54

Correct. 13 PSI minimum at idle.

I like your slant on Chinese low-bidder quality control. Well stated.

junkyardjeep

With the mechanical gauges im reading 14 at idle and shoots up to around 30-40 when I rev it up. So the problem was the sensor. I replaced the sensor and all is well. Thanks again cherokeeforum.

tjwalker

Glad we could help. Easy and inexpensive fix.

This is why I sound like a broken record sometimes, but a testing based strategy is always the best way to proceed.

Much more efficient and cheaper in the long run than "throwing parts" at a problem and hoping you get lucky!