jeep 4L oil pressure

Oil pressure depends on pump quality and bearing clearance both. If you put a new pump on an engine with bad bearings, then you didn't help yourself much. Did you check the accuracy of the oil gauge before installing the new pump? Isolated oil pump failures are rare, because the pump is the best lubricated part of the engine. They do happen, of course, but they are rare.

Earle

Thank you Earle. I was thinking that was the problem but, I was in denial and hopping for another answer.

I'm with Earle on this one, but with a caveat.

The oil pressure sending unit could be a problem area that you should look at before you go in search of the bad bearings. The sending unit uses a variable resistor of some sort mounted to a diaphram. The diaphram can get a hole in it, and give strange oil pressure readings. It is common for the oil pressure to drop at idle, then come back as the engine speeds pick up, but I don't think that a drop all of the way to zero is right.

Well, if it really goes to 0 at idle, you will 'hear' about it. The valves will start clacking really fast.

Usually that trouble is the sending unit above the oil filter. They are poor quality and fail lots. The fact it got worse also implies the sender is fast going dead.

Second is a main bearing, but again if you have mains that bad, you should be able to hear a knock or rumble vibration at idle.

Mike

ansky wrote:

My '95 ZJ does the same thing and has for a couple years...I've jus been to cheap and lazy to change the sensor...one of these days! kinda freaks u out for the first while watching the gauge drop off to zero... Jeff '03 TJ & '95 ZJ

Is there a 't' fitting for mechanical oil gauges? ( To be able to leave the original sender attached, and attach the line for a mechanical gauge?) I would have attached a mechanical pressure gauge long ago on my son's wrangler, but haven't done so because of the computer turning on the 'check gauges' light and sounding a tone when the pressure sender is disconnected.

thanks!

cal

Cal did pass the time by typing:

Any brass T fitting that has the right threads will work.