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Topic: Internal Engine Harness for M11 ISM (Read 1553 times) previous topic - next topic

Internal Engine Harness for M11 ISM

While under the hood (or is it under the bed) I observed what appears to be a leak where the internal engine harness enters the head.  I know this is 12 pin connector that the computer uses to communicate with the injectors.  Included are a couple of pictures showing the problem.

Has anyone else had this problem with the M11 ISM and what type of seal is used to fix it.  I would assume there is an O-ring and nut.  I plan to make this repair within the next few days and would appreciate any help or suggestions.

Thank you:
The combined knowledge of this site is unbelievable.

Jason
Jason
1999 U320 36'

Re: Internal Engine Harness for M11 ISM

Reply #1 –
Not had the issue yet at 105,000 miles.  If/when it shows up, know the Cummins shop can/ will fix it, so not a large concern.
Dave M

Re: Internal Engine Harness for M11 ISM

Reply #2 –
None at 111k
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Internal Engine Harness for M11 ISM

Reply #3 –
A friend of mine had an intermittent issue with the internal wiring harness on a 95 M11. I bought a spare for our 95 which I never needed. It's probably the same harness as the ISM. The harness is internal to the engine and connects the injectors to the ECM. The internal harness has a foam gasket which is integral to the connector that passes through the cylinder head. It may be possible to make some sort of gasket to replace the foam, worst case replace the internal harness. I don't think it was very expensive.
I would make sure the electrical connector is properly tightened on the outside first. To get to the connector gasket will require removing the valve cover. The connector sealing is on the inside of the valve cover.
David Bethard
2003 U320 - 40ft. Build #6159
ISM 500hp
2006 Jeep Liberty CRD
2021 Honda Goldwing DCT

Re: Internal Engine Harness for M11 ISM

Reply #4 –
Dave:

Thanks for the help.  Great to have some insight of what to expect.  Looks like this leak is not a very common problem and hopefully an easy fix by tightening the connection.

Jason
Jason
1999 U320 36'

Re: Internal Engine Harness for M11 ISM

Reply #5 –
Although I don't have your issue, may I suggest that after tightening things up and giving it a good cleaning... keep an eye on it and if it's ends up not turning into or being a situation, leave it alone (unless you have an urge to fix it.) 

Plug into sales of (used) M11s and notice that leaking harness issues are typical of this series Cummins.  I had a Class 8 that I lived with for several years (& a few cans of spray cleaner) rather than getting into something that IMO was close to being at the bottom of my concerns list for repairs.

There is (also) a silicone spray sealer you may want to give a try. pc
S/W Houston 95" U320C SE/40' 
Build #4778  Cummins M11
Repairs & Covered RV Parking (BAO)
PPL is close..
 

Re: Internal Engine Harness for M11 ISM

Reply #6 –
Thanks pocketchange.  I looked at it today and tried to wiggle the plug to see if it was loose.  It was tight and no war to tighten from the outside.  I like your idea lf just cleaning it up and watching it.  It is a very slow ooze and probably not worth creating more of a problem.  I will put this job on the back burner.

Jason
Jason
1999 U320 36'