Oil in PCU (filled with motor oil)

thuddles

thuddles

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When I took out the plugs for the PCU they were all filled with motor oil. After removing the PCU, it was very heavy, i took out the grommet. and oil leaked out for quite some time. I sprayed some electrical cleaner in the hole and more oil came running out. Literally the entire thing was filled with oil.

Is there anything i can do?? Is it gonna be fine since it was filled with oil before the upgrades?

I'm doing a large electrical upgrade including a new 1600 watt amp and 2AWG battery cables. I know this controls the airbags as well. When i hook everything back up will it be ok??

Thanks in advance for any help

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You need an oil pressure sensor, probably a new harness, and a new PCM.
 
Any history that points to how the oil got in there? It seems to be a stretch to the possibility it made its way in there via the wiring harness from the oil pressure sender. The oil itself wouldn't worry me that much, it can be flushed away, but I worry about fine metal particulates in that oil that could find their way to a part of the computer that could cause problems.

1600 watts? What is that amp's RMS output?
 
Lou said:
You need an oil pressure sensor, probably a new harness, and a new PCM.
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It was running before, is that really necessary?

Jerry Bransford said:
Any history that points to how the oil got in there? It seems to be a stretch to the possibility it made its way in there via the wiring harness from the oil pressure sender. The oil itself wouldn't worry me that much, it can be flushed away, but I worry about fine metal particulates in that oil that could find their way to a part of the computer that could cause problems.

1600 watts? What is that amp's RMS output?
Click to expand...

Honestly not sure how the oil got there. I've had the jeep for 10 years, its sat for about 2 and now i'm trying to fix it up. I had the head gasket replaced when i first got it. I remember I put synthetic oil in it a few times, oil seeped out of everywhere and sprayed all over the engine bay, that was .... 6 or 7 years ago. I've gone royal purple since and have 0 (oil) leaks currently. When it was hooked up, the jeep started right up and ran smoothly,

How can oil seep up wire harness? The harness had a little oil in it, but just near the battery. I had a few nicked wires that I had to repair in that area, I cleaned up all the wires the best i could but it didn't seem like all of this oil came up the harness...

I've cleaned it out as best i can. Am i ok to try to plug it back in and test it out? Or do i risk blowing an air bag or some other weird jeep thing

Here's the specs for the 5 channel amp - https://www.kenwood.com/usa/car/excelon/x801-5/spec.html
 
This is a new one on me for a Jeep/automobile. I do know in the big truck industry some manufacturers do have a problem with oil wicking through the oil sending unit harness and the oil level sensor harness back to the PCU/ECM. When it happens on a big truck generally you can get an anti-wicking harness to stop the problem, but when the ECM/PCU is full of oil it gets replaced.
 
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On topic:
Maybe a previous owner changed the oil and used a filter with the right pipe thread but the wrong sized rubber gasket. If so, it only took about 30 seconds for him to find out he did that because at least 1/2 a quart (probably a whole quart) came spraying out from that "oil fountain" in every direction during that 30 seconds.

Kinda off topic but related:
I could be wrong about the PCU oil because when I did that it was in a CJ and there was no such thing as a computer small enough to fit under the hood but I did have oil dripping onto the floor out of the heater box for a couple weeks/months(IDR) because some of my "oil fountain" followed the heater hoses to end up in there.

Very off topic:
I used to know what vehicle that filter was really for. I can't recall but the only difference was the diameter (not the cross section) of the o ring gasket and that wasn't enough to not feel like it tightened up.

Totally off topic:
FWIW, I wish I'd have had my dad's Super 8 camera and a roll of film handy back then. That home movie would have gotten so may likes and thumbs ups (and some horn beeps) if I had hung a sheet in the yard and played it every night from sunset to 1 AM when signing off with the National Anthem would have been expected.
 
the PCM does not control the air bags. That module is inside of the jeep in front of the center console.

I would not be too worried about replacing the PCM or harness unless you are having issues. I would however disconnect the oil pressure sensor connector and see if its full of oil. If it is I would ATLEAST replace that sensor and clean up the connector.
 
John Cooper said:
This is a new one on me for a Jeep/automobile. I do know in the big truck industry some manufacturers do have a problem with oil wicking through the oil sending unit harness and the oil level sensor harness back to the PCU/ECM. When it happens on a big truck generally you can get an anti-wicking harness to stop the problem, but when the ECM/PCU is full of oil it gets replaced.
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When i was watching it pour out i was kinda thinking am i being pranked? lol

JEEPCJTJ said:
On topic:
Maybe a previous owner changed the oil and used a filter with the right pipe thread but the wrong sized rubber gasket. If so, it only took about 30 seconds for him to find out he did that because at least 1/2 a quart (probably a whole quart) came spraying out from that "oil fountain" in every direction during that 30 seconds.
Click to expand...

PO was something else...When I bought, the headlights were ran through a separate switch while power still running to the dash. He had 30's on the front and 31's on the back, which blew out his TC so I bought it with the front drive shaft sitting in the trunk....... Unfortunately i do believe that the oil was from me because i remember opening up my engine bay and being like wtf happened here? and it was on the oil filter side like you described like i said, i switched to royal purple and a quart of snake oil and i have no leaks now...

Lou said:
the PCM does not control the air bags. That module is inside of the jeep in front of the center console.

I would not be too worried about replacing the PCM or harness unless you are having issues. I would however disconnect the oil pressure sensor connector and see if its full of oil. If it is I would ATLEAST replace that sensor and clean up the connector.
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Ok thats good news, i guess i'll throw it all back together and hope for the best.
 
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I guess it keeps water from getting in it lol... I would dunk it in rubbing alcohol a few times and let it dry out in the sun. I’ve done this a good many times with phones that friends dropped in water.

I really don’t get how this could happen though.
 
I work on heavy duty Diesel engines and we commonly see oil intrusion in the ecm connectors from injector pass through harnesses that run inside the valve cover. I have also seen it from oil pressure sensors but I have NEVER seen oil drain out of an ecm. I have also never pulled a drain plug on an ecm.
 
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Lou said:
I work on heavy duty Diesel engines and we commonly see oil intrusion in the ecm connectors from injector pass through harnesses that run inside the valve cover. I have also seen it from oil pressure sensors but I have NEVER seen oil drain out of an ecm. I have also never pulled a drain plug on an ecm.
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I have only seen oil in the ECM on Volvo trucks.
 
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Lou said:
I work on heavy duty Diesel engines and we commonly see oil intrusion in the ecm connectors from injector pass through harnesses that run inside the valve cover. I have also seen it from oil pressure sensors but I have NEVER seen oil drain out of an ecm. I have also never pulled a drain plug on an ecm.
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This is a common issue with old Mercedes transmissions. ATF fluid everywhere!
 
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Are the ECM/TCM mounted lower than a oil pressure sensor in those trucks or something? Thats the only way I can picture it myself.
 
oil pressure sens
DWR said:

I guess it keeps water from getting in it lol... I would dunk it in rubbing alcohol a few times and let it dry out in the sun. I’ve done this a good many times with phones that friends dropped in water.

I really don’t get how this could happen though.
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Maybe i'll try that as well, i sprayed electrical cleaner in/on it but i would like to submerge it to really get everything as possible out.
Lou said:
I work on heavy duty Diesel engines and we commonly see oil intrusion in the ecm connectors from injector pass through harnesses that run inside the valve cover. I have also seen it from oil pressure sensors but I have NEVER seen oil drain out of an ecm. I have also never pulled a drain plug on an ecm.
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I mean the drain plug is there for a reason right??

Vidar said:
It’s called PCU Fluid and needs to be changed every 84,352 miles. You should also change your Blinker Fluid while you are at it.
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i'm at 180k, way past due!! haha



is there anyway i can take this thing apart? or should i leave it together? i unscrewed the 7 screws on it but it doesn't seem like it loosened anything.
 
thuddles said:
When i was watching it pour out i was kinda thinking am i being pranked? lol
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To be honest, when I saw this thread last night I was ready to respond "alright, Kutcher, where are you hiding?" but since I had nothing to contribute it felt like a dick move so I kept my keyboard mouth shut.
 
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