Ford Powerstroke Diesel Forum banner

Injector Misfire, Sticky IPR, HPOP, ?...

19403 Views 168 Replies 13 Participants Last post by  bismic
I'll try to be as concise as possible without being lengthy. Please ask questions if I forgot to include the data. This problem only happens once in a blue moon, so it's been hard to track down.

Every so often after running the truck on a long run (>150 miles), I pull in somewhere, shut it off, go inside for 10 mins and come back out to start the truck. Truck fires right up, but then starts to act like it's missing on a cylinder. Put it in gear and it gets worse. My normal IPR at hot idle is 21-22%, but when this happens, IPR stays steady at 25%. My normal ICPv at hot idle is ~0.8 - 0.85v (~580psi), but when this happens, ICPv jumps around from 0.8 - 1.0v and ICP jumps with it (~580 - 610psi). If you give it some pedal and pull away from the parking lot, stoplight, etc. the truck goes right back back into normal rhythm with ICP & IPR values & the feeling of a misfire stops.

I have changed ICP sensor & pigtail just to rule that out, but plan on unplugging the ICP sensor the next time it does this to see if it clears up.

Do you think the IPR is sticking? Kinda seems like to me that it wants a bit more ICP, so it commands the IPR to 25% to get that last little bit, but it might not be moving to that position. I did try to take off the IRP when my turbo was out a couple years ago, but it was in there TIGHT and I was on a time crunch, so I figured i'd leave well-enough alone! Wishing I had pulled it now.

What say ye? Ideas?

@bismic @Hydro @TooManyToys

-jokester
61 - 80 of 169 Posts
Thank you very much! Just bought the Matco T40 and T45's along with the Alliant brush kit. Had to pay a bit to get them here quickly, but, such is life...it's only money, right? :D

I think i'm 15/16ths ready now LOL

-jokester
I knew Matco made some that were a good length, it took me a while to find the part number and get the link. I thought that they would be more reasonable than Snap-On!! I have a set of the S-K, but they actually may be a bit too long, so I deleted that link.
  • Like
Reactions: 2
@jokester00 as I like to say I'll make more money tomorrow

Sent from my SM-G973W using Tapatalk
Every time the tool truck rolls in the shop lot
  • Like
Reactions: 3
I probably should have put a link to the video in my earlier post. You can't get more backyard simple than this. I did upgrade to the larger diameter shaft, and it's a better feel. Sorry for the voice; most of the year, I have issues. I probably should redo the video, but I'm so behind on what I want to do.


  • Like
Reactions: 3
I posted these in another thread, but I use them a fair amount, so I thought I would add them here (there are a lot of other choices out there for similar tools):




Williams also sells the little ratchet -- they make a lot of the tools for snap-on

  • Like
Reactions: 2
I have Williams tools from the '50s.

There are so many neat tools on the market today.
  • Like
Reactions: 1
You guys posting all these cool tools - it's like you're BEGGING me to spend money :D

-jokester
  • Like
Reactions: 2
Tell me about it. I just spent $400 on something I really don't need. Well, there's always eBay so you are just renting it.
  • Like
Reactions: 2
My perspective is that NO tool can be considered "not needed". It simply is not needed YET!
I'll have to remember that when I'm explaining my credit card statement to the wife ROFL! 🤣

-jokester
  • Like
Reactions: 3
I'll have to remember that when I'm explaining my credit card statement to the wife ROFL! 🤣

-jokester
Jokester took the words out of my mouth. Actually, she doesn't complain; it will be the guy on my shoulder. He started as I was punching in the credit card number.
  • Like
Reactions: 3
Ladies and Gentlemen,

Such as life goes, there are times you have to bite the bullet and pay for truck work. Something came up and I couldn't get to swapping out the injector by the time we leave on Sunday for our camping trip. Rather than risking a soured trip with truck issues, had a guy I thoroughly trust change it out for me. Gonna drive it around a ton the next 3 days to test it out. Hopefully she's fixed...crossing my fingers. I will say that after the work when I picked it up yesterday, as soon as I fired it up I could tell a difference in the idle (better). This morning - same thing...idled smooth as glass. I could hear that stable HUMMMMMMM again that has been missing (missing...LOL - see what I did there :D ). Some of you on here will know what i'm talking about - if you don't, you may need an injector LOL.

Here's to good guys who happen to be mechanics you trust when you can' get to it! 🍻

-jokester
See less See more
  • Like
Reactions: 3
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.

Sent from my SM-G973W using Tapatalk
  • Like
Reactions: 2
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
See less See more
  • Like
Reactions: 1
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.

Sent from my SM-G973W using Tapatalk
  • Like
Reactions: 1
Yeah, that's twice now within a few hours after reprogramming that specific tune that the truck has done this! I can't seem to get that out of my head...

I'm leaving everything stock for a week or two and see if it happens. If it's good, i'll load another tune from another writer and go another couple weeks. If it doesn't do it still, i'll load this specific tune back and see if it does it. If so, I have my answer. If it doesn't, I guess i'll drive the old gal till it does :D LOL

-jokester
  • Like
Reactions: 1
Well, i've been running stock on my FICM and PCM for 2 weeks now with nary an issue...

I loaded a PCM tune last night (not the tune that seems to give me issues - a different one), and it tuned just fine. Took it for a 10 mile drive and no issues. Went back home to load my FICM tune. Pulled the relay and to my surprise, it had a big crack in it! Hmmm..wonder when that happened?? Swapped it out with my spare relay and tuned the FICM. Took the same 10 mile drive and all good!

I do think my #8 injector that was swapped contributed to the random misfire when hot. However, i'm crossing my fingers that this FICM relay thing might have been the issue of the erratic idle. Guess it could still be the tune as well, but this weird erratic idle thing started happening when I first loaded that tune, but I also tuned my FICM at the same time. Wondering if that relay had a crack then and I didn't see it...

Thoughts?

-jokester

Finger Nail Gas Thumb Font
See less See more
A crack in the case really should not hurt the relay, unless water got in and corroded the contacts
Pop the cover off and look inside
  • Like
Reactions: 3
A crack in the case really should not hurt the relay, unless water got in and corroded the contacts
Pop the cover off and look inside
I saved it to do FA. Will pop the cover off when I get home tonight. I'm hoping to see some corroded contacts from moisture intrusion...

-jokester
  • Like
Reactions: 2
61 - 80 of 169 Posts
Top