Computer leaks oil ??!!

[MMeier]

Guy at work has a 1998 Grand Cherokee that will shut down at the least opportune times. When he pulls the connector off the computer ,it leaks oil. Cleans it up , put back together, runs fine for abit, then same thing. Bought another computer, same thing ? Some wiring harness issues, or what ?

 

[Mikey-KE7LBB]

This post reminds me of a thread I read on a TDI forum a few years back when I had a '98 Jetta.

Turns out that the coolant level sensor (and wiring) were allowing coolant to wick through to the computer and nearly every wire attached to it! They even found it in the tail lights!! The link below isn't the exact one I read, but you can dig for it if you have time.

http://forums.tdiclub.com/showthread.php?t=145275&highlight=coolant+wicking+wiring

Never heard of it happening before, but I suppose it is possible for oil to do the same thing when conditions allow it. I would suggest unplugging the oil pressure wiring to see if there is oil present and go from there.

 

[BK]

Sounds like Mikey hit on it to me.

Some computers maybe potted , most are just conformally coated, but they aren't sitting in an oil bath in their cases.

The oil is collecting from where ever it's leaking from.

If you can't find traces of oil on the surface then....the harness is either in a split loom or tape wrap, either way open up the harness and try and trace the oily wires back to the source.

Or clean up the engine well, get some die and a UV light, start with the engine oil.....see if you can trace it back to a sensor or area on the engine.

 

[Tuesdak]

The oil leak through the wire is from a sensor that has oil. Likely the Oil pressure sender but could be crank/cam sensor combined with a bad PCV. If you pull connectors off the engine sensors you will find the oily one. I have seen coolant temp sensors and a lift pump also do this. Yeah diesel fuel leaking out of a wire connector!

Oil will insulate wiring connectors and break the connection. You can pierce the wire insulation by the ECM after fixing the leak and let the pressure and remaining oil leak out there. Otherwise the oil filled wire itself needs to be completely replaced.

Another likely problem is the ECM has cracked solder connectors. Replacements are rebuilt and may not be 100% fixed.

Wiggle test the ECM harness by the ECM and see if the engine stalls. A sign of cracked solder connectors on the ECM board.