45 seconds of confusion...

[JimT]

(05-04-2021 )Smokin64 Wrote:  -Note 1: ABSOLUTELY no codes at all, unless it misfires long enough to throw a "cylinder unbalanced" fault, (thanks Captain Obvious).

Bad programming can and will suppress fault codes from being communicated.

(05-04-2021 )Smokin64 Wrote:  -Note 2: Injectors and o-rings were replaced about 4k miles ago due to 25.3% fuel dilution. Turns out the cylinder head had a crack at the upper fuel port for injector #3, and at 25% fuel dilution and 600k miles since the last overhaul, it got overhauled again. This rough idle starting issue began about 1 week after the overhaul, but I have no more fuel in the oil.
-Note 3: The injectors are from Delphi, not Cummins. (not my choice)
-Note 4: Injector cutout test shows no problems, I can hear every cylinder no matter what RPM. However I do not have Insite so I can only cut out one at a time. (not my choice)

If your a mechanic and DON'T have the proper software to work on an engine then that IS YOUR CHOICE. Whether you buy an official version or find a free copy on the internet or pay a couple hundred on ebay for a chineese inline 6 that comes with the software. Either way, it's a tool any modern mechanic should have, just like owning wrenches and sockets.

(05-04-2021 )Smokin64 Wrote:  -Note 5: Cylinder performance test shows all are working correctly
-Note 6: Metering and Timing solenoids have already been replaced because someone told the owner that they were bad. I would have tested them and taken them apart, but that wasn't my call to make.
-Note 7: This truck was deleted by {THE HORRIBLE PLACE IN uTAH} at about 550k miles, dropped a valve and got overhauled at 770k miles, and then the fuel dilution overhaul at 1.3M miles.
My thoughts: probably not an electrical or sensor issue since I don't have any codes, and probably not a fuel pressure issue since the truck runs great after the miss clears up. I've tried for 3 weeks now to find a test ECM, can't find one near eastern Iowa. I watched Rawze's video and ordered the injector bubble tester kit today, maybe that will show something. Has anyone heard of anything like this before? Sorry for the rambling..

As for the issue, I could make guesses, but I don't know enough about the 870/871 to say anything useful. However, if you're concerned about the condition of the ecm then try giving it a few good taps while the truck is running. However it doesn't seem to match your description. Programming on the other hand is most likely the main underlying problem for this truck, coupled with (as you describe) half-assed clowns working on it that don't know what the hell they are doing and just throw parts at it until something happens.