M-11 379 Injector Plug issues

[pbateman]

Hey fellow DK friends starting this thread just to see if anyone else has run into this issue with the M-11 379 engines. The plug that is located in the front of the rocker box which hooks to the injectors. The o-rings that go around this plug are very thin and eventually wind up leaking and the wires on the outside plug become oil soaked and from the heat of the front of the engine its eventually makes the wires very brittle and they begin to melt together and the end result is it winds up causing a bunch of unnecessary fault codes or winds up showing that injectors are bad when they aren't. We have ahd about 25 trucks with this issue and the mileage range is about 350,000 and have have to change out the secondary ECM harness. Would like to know if anyone else has run into this issue and what your experiences have been.

[djz4248]

the best i have found is to clean both ends of conectors real good with brakeclean or carbcleaner,install new orings,put good silicone sealer (gray) on connecter and put back in rocker box. then i seal where wires go into connector with same stuff on both harnesses getting it woked in between the wires good. i think a lot of the oil is comming through the wire seals. real nice place for that connector isnt it.

[pbateman]

yeah it is djz but the issue I have been having is because its been caught so late the wire covering is already melted away in the plug and causing the wires to show up bare and causing all kinds of issues. Once the new harness is installed that is what i do use a good heat resistant silicone.

[djz4248]

cummins also sells a repair pigtail instead of replacing whole harness.

[ricz]

Wrap it with heat shield tape!! Automotive parts stores sells them.

[pbateman]

thanks for the replies guys will try this instead of replacing the whole harness. will be a lot easier on us here at the shop

[pbateman]

hey Dk friends just have a question. Wanted to know if there is a way to bench test an injector before you actually install it into an engine? have had several issues where I have gotten injectors from Cummins and after the tope end was all put back together found out I had some bad injectors. So was just wondering if there is a way to test them before installing them. Thanks for any input and help in advance!!

[djz4248]

that happens when adjusting inj and bottoming out too tight. plunger sticks inside. only real light pressure then back two flats. if one does stick i usually remove cover and take a rollhead bar and stick pointed end in the allen screw head on the spring retainer on injector and give it a whack. usually works.

[pbateman]

hey djz thanks for the info but where it seems to be having the issue is it like the electronic cables on the top of the injector is where the issue is is there any way to ohm it out? thanks for any input in advance

[djz4248]

should be 0.5-1.5 ohms. i have only seen a few with bad injector pigtails or coils. never had problems with new ones. i replace 2-3 m11 a week. usually sol valve problems. sometime if late at night or in a jam i unscrew solonoid and clean valve. usually find sliver of metal holding valve from closeing. gets you out of a jam but normally only lasts 3-4 months before failing again.

[pbateman]

Thanks DJZ appreciate the input.