[TwinExcursions]

Unplug ICP and plug back in. Read you already replaced pigtail and ICP. I need to do same (when I get the time - parts sitting in toolbox saying "hello") but as stop gap I have been unplugging and plugging back in and makes similar problem go away for awhile.

Also @Hydro has good info.

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[TwinExcursions]

Almost looking like you are possibly chasing a chafing issue in wiring harnes(s). Don't remember if you checked for this.

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[TwinExcursions]

The differences in the readings will be subtle
I would suggest copying them down and adding to a graph (spreadsheet) so you can easily spot the variations

Could easily be a chaffed harness, I would think a code tho
or loose connector on an injector or the ficm --
you would need to look inside the female terminal at the small spring leafs on the affected injector

I always kept spare terminals in my tool box, to use as a trial fit in the female terminals
that made it easy to spot a loose fitting terminal

Always learning from you - really appreciate.

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[TwinExcursions]

Torque Wrenches - I have a couple click type from Harbor Freight, but those are probably not accurate enough for this job, correct? Any recommendations besides ones that cost $500? Also, where did you guys get your extended T40/45 Torx in 3/8 or 1/4 drive?

I have the torque specs are as follows (please correct me if i'm wrong!):

1. Injector hold down (mine's an '05, so i'm assuming it's a T40) - 24ft lbs (26ft lbs for T45's)
2. Oil Stand Pipe - 60ft lbs (don't need to install new ones, right? Mine are the updated 12mm's)
3. Oil Rail Bolts - 120in lbs (10ft lbs)
4. Valve cover bolts - 80in lbs (~6.5ft lbs)

I'm 7/8ths of the way to being ready to change this thing LOL

-jokester

Get your torque wrenches calibrated/tested and you will know if they are in need of replacing. I get mine done every couple of years, at work they are done yearly (regulations state they have to be done yearly).

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[TwinExcursions]

I'm a dead weight tester for the torque wrenches. Spring scale; then I have to worry about the spring scale calibration - it never ends

I just rely on certified calibration company - not cheap but I have piece of mind when it goes click I know it is correct. Certain things just have to be accurate IMHO. My volt meters/ammeters/etc for work all get regular calibration certs as well.

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[TwinExcursions]

@jokester00 as I like to say I'll make more money tomorrow

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[TwinExcursions]

Glad to see you finally (fingers crossed) got this fixed so you can have a stress free holiday.

Enjoy your trip - I'm a little jealous. I won't risk my trailer due tou our out of control fire situation.

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[TwinExcursions]

Bringing this back to the top...

Life has been good since the #8 injector replacement. Yesterday, I returned my PCM tune to stock to get some info, then re-loaded the 40HP Tow tune. I drove to my daughter's basketball game and on the way home, I was sitting at a stop light and got a 1 second surge "WHOMP" like I had pressed the accelerator, but my foot was on the brake. Hmmmm...that was odd. By the time I got home, it was idling weird and erratic like the video I posted earlier in this thread. Sounded just like this video (not mine - just the best video I could find to replicate the idle I had):

6.0 ipr issue - YouTube

The last time it did this when this whole thing started, I had just loaded the same PCM tune for the first time that morning, and the issue started happening that afternoon/evening. Knowing that, when the issue started up again yesterday, I was thinking that it was possibly a tuning issue with that tube, so I returned the PCM back to stock and test drove it - it was still doing it. I also returned my FICM back to stock (was on Atlas 40) to rule that out, and it still did it with the truck PCM & FICM tune stock as well. When it acts up, FICM MPower, VPower, and LPower are all good as well as FICM sync & Cam/Crank sync, so i'm thinking it's not the FICM (still not totally ruling it out though).

My thoughts are:

ICP sensor/pigtail - which has been changed in the last year
IPR valve/pigtail - i'm gonna poke around today and see if I can get it to act up
FICM - Not sure on this one
Injector - again...gotta get it to act up to rule this out!

I spent 2 hours driving around last night looking at my monitor and NEVER COULD get the truck to act up again! Did I mention that I HATE intermittent issues...?

I REALLY thinking about swapping out the IPR. I found a lot of threads with similar idles as mine, and the IPR swap fixed theirs, but I HATE throwing parts at the wall hoping it sticks...

-jokester

@jokester00 when mine did this the ICP pigtail cured it and been good for a long time. Maybe double check your pigtail connections from when you replaced it - been a wet winter maybe some corrosion has happened? .

Seems odd after program change though. Disconnect both batteries for a "hard" reset of everything, don't know enough to know if it does it on our trucks but industrial computers I work with sometimes require this after programming mods.

IPR is also worth investigating - monitor ICP voltage/commanded IPR% and see if any odd fluctuations.

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[TwinExcursions]

If the relay was damaged it would cause running issues at all rpm's not just idle. If damaged it would be a consistent issue no matter what rpm the motor is at. Possibly worse at higher rpm as the current draw would be higher on the contacts in the relay due to more current going to the FICM (more injector on/off pulses at higher rpm - this is also ignoring the back emf of the coils when they shut off which will increase with rpm).

IMHO

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[TwinExcursions]

Only way I could figure a cause for it, but I wouldn't think @jokester00 would be one of those people!!!!!

Have to agree with that

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