Hey longtime listener, first time caller.

Looking for help identifying this part. It's located on the passenger side of the block, just above the oil pressure sender. It looks like it was attached to a bolt on the block, but it's tab has corroded off. It has a single wire that goes to it, Green with a Pink stripe.

The Jeep is a 2000 XJ, 145,000 km, Canadian Market, good shape, and has been good to me.

Two days ago, the oil pressure gauge has begun to read 0. Flat, nothing, no gain. Engine seems fine, lots of oil flow, fills the head rapidly.

New pressure sender installed, no change.

Anyone with idea's or assistance? I'd be every so grateful, this ones got me stumped.

 

My first thought is...Are you sure the piece with the green/pink wire was attached to the tab on the block? It might just be a coincidence it is laying next to it and it actually came from somewhere else.

 

Hard to tell from the pictures. Can you trace the wire back to anything like a harness or some other sensor?

On a side note.... Get rid of that Fram filter. The general consensus around here is that they are junk. I like to only use Wix/napa, purolator or mopar.

 

It's a radio interference condenser, it blocks the electrical frequency generated by the alternator from interfering with your radio reception. Most modern engines have them mounted on the engine somewhere out of the way, or built into the alternator themselves. It's supposed to be mounted to that tab. Shouldn't have any effect on oil pressure though, possibly a broken wire to the oil sender or the gauge is busted?

 

Thanks for the Fram heads up.

 

This is kind of unrelated but this is also why your should never run your CB radio off a cigarette lighter plug of off your fuse box.. Run the power straight from your battery.

 

That's an Ignition Coil Capacitor.


Nothing to do with the oil pressure sensor. You may have a broken or chafed wire going to the OPS.

 

Aha!

Ignition coil capacitor, that's the beast right there. Some one has far less underhood corrosion than I do!

Thanks so much, #1 solved.

Is there a place, if it is a chafed wire for the Oil Pressure, that is more common on the XJ to have a problem? I did a good scope under the hood, can't find anything suspicious. I've giggled gauge cluster, checked at sender pickup, checked grounds. Most of the harness is wrapped in a loom, makes it a bit tougher....

Thanks!

-I

 

With a helper in the cockpit, start the engine, see what the oil pressure indication is, wiggle the wiring harnesses and see if the oil pressure indication changes.

 

I don't know how common this is, but the last time I had an oil pressure sender issue on my 2000, the wires coming into the oil pressure sender connection had all had their insulation rotted away. There were bare wires there, and when I touched them the remaining insulation just flaked off.

I had to cut away some of the loom to get back up into the wiring harness to where there was some good insulation. My oil pressure sensor had been leaking, and from what I could tell, the insulation rotted where the oil had been in contact with it. I spliced new wires in past that point and haven't had any issues since.

Now, I will say that with mine, it shorted and caused the oil pressure reading to peg at 80 psi. So your problem may be different. But it's not a difficult thing to check.

 

Ok, good info. I'll take some of the wrapping off. Wires look good for the first few cm coming out of the plug, but there is some oil coating on things.
Just so I am aware, is 80 the full scale reading? Reason I ask is the first sender showed 5.4b for a bit, and alternated between 0 and full scale (5.4) before the pressure sender change.

Thanks!

 

The US market gauges in the XJ have a range of 0 to 80 psi. If your gauge is in bars, 80 psi = 5.5 bars.

If the meter was pegging at the highest end of the scale, it was probably grounding out. With mine, I replaced the oil pressure sender and still had a pegged reading on the gauge. I put my hand down there to wiggle the connector while the truck was running, but in doing so I pressed against the wires, and the truck quit. When I cranked it back up, it ran rough for 30 seconds or so before smoothing out again.

After that I had no reading at all on the gauge, as you described. By that point I had already discovered the missing insulation. I bought a replacement connector at a local auto parts store that had several inches of lead wire on it, so I cut into the loom to find some good wire and spliced in. I have had zero problems with it since then, although writing that probably just cursed me.

 

Thanks everyone!

Turns out the ground wire just inside the connector for the sender had corroded away.

Rang out the harness, and nothing to the plug, but the signal and +5v was good.

New pigtail was available, and that fixed things up.