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

19400 Views 168 Replies 13 Participants Last post by bismic, 24 d ago

jokester00

Discussion Starter · Jun 29, 2021

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

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Hydro

· #21 · Aug 7, 2021

when you do the cylinder cutout -- look at for each cylinder
RPM
IPR
ICP
Fuel pulse width
Load
Misfire - I forget what it is called

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jokester00

Discussion Starter · #22 · Aug 7, 2021

Did the cylinder disable test with AE. Got a definite change in idle with each injector. However, not much of an change with any PIDs during each disable...not what I was expecting. Sorry, couldn't find engine load or which misfire you wanted in AE. PIDs shown are as follows:

RPM: Bottom left
ICP: Top Middle
ICP Desired: Middle Middle
Fuel Pulse Width (uS): Bottom Middle
ICPv: Top Right
IPR: Middle Right

I won't post all pics, but each cylinder was VERY consistent with all others cylinders when running, and changed consistently when disabled. Don't mind my reflection 😁

Cylinder 1

Cylinder 8

Haven't done bubble test yet, but how often does compression leaking into the fuel seal itself? I thought it would get worse the longer the truck ran, which is not my case.

-jokester

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TwinExcursions

· #23 · Aug 7, 2021

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

Sent from my SM-G973W using Tapatalk

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jokester00

Discussion Starter · #24 · Aug 7, 2021 (Edited)

Bubble test complete...no bubbles!

And the tangerine pomegranate diesel smell again...GEEZ!! 🤣

-jokester

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jokester00

Discussion Starter · #25 · Aug 7, 2021 (Edited)

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

Sent from my SM-G973W using Tapatalk

I have not checked for chaffing yet. I was kinda going off the Injector 8 code and the higher duty cycle when my truck acted up. I did wiggle the FICM plug harness wires and the injector connector wires at the injectors on the even side when it was misfiring, but nothing changed.

-jokester

Hydro

· #26 · Aug 7, 2021

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

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TwinExcursions

· #27 · Aug 7, 2021

Hydro said:
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.

Sent from my SM-G973W using Tapatalk

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jokester00

Discussion Starter · #28 · Aug 7, 2021 (Edited)

Man, I ran the dogsnot out of this thing trying to get it to act up and it didn't skip a beat! A small clip idling after I ran it hard...

Also, one piece to note...when I pulled the top fuel filter to do the bubble test, I found a slight twist in the filter itself that wasn't there when it was installed. I've never pulled a filter when the truck was warm before, so I have nothing to compare to (I would assume it would be a bit more flexible), but I've never seen a twist in my top filter before when I've changed them normally. Missing piece of the puzzle, or am I grasping for straws? Should I change it out with a new one that's not twisted (mind you, this started right after I did fuel filters, but I've never seen a loss of pressure on my gauge).

I'm not a graph guy, but here's the data when I disabled each cylinder.

-jokester

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jokester00

Discussion Starter · #29 · Aug 7, 2021

The more I think about this, from what I've read, P0284 is either a cylinder, valve, or injector (mechanical). Pretty sure I've ruled out 2/3, unless I have an untermittent sticky valve. What are my odds of that?

-jokester

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Hydro

· #30 · Aug 7, 2021

One quick thing I see from your chart -- then I am heading to sleep
the ICP voltage and pressure do not correspond always
the voltage may be using some hidden decimals, not sure
cyl 7 - 0.85 volts - 586.68 psi
cyl 5 - 0.86 volts - 576.15 psi

unless you mis-copied the numbers?

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bismic

· #31 · Aug 7, 2021

Ultimately, you might consider swapping #8 and say #6, to see if the code remains at #8

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FordDoctor

· #32 · Aug 7, 2021

Unfortunately without more advanced tests you are not going to efficiently or properly diagnose a faulty fuel injector - what you HAVE been able to has not revealed any concerns. If the cause is electrical it will almost always set a circuit code. Chafing injector harnesses will either set a code or shut the engine off instantly. All you have is a symptom (misfire) and an cylinder contribution code. (P0284) Short of a visual inspection all you can really do is swap the injector with another cylinder and see if your misfire moves with it or simply replace the suspect injector. Swapping WILL require new seals.

Of course, performing diagnostics while the symptoms are present would be ideal.

A bubble test more than likely will not reveal anything. Your symptoms do not point to combustion gasses leaking past the injector tip. Whether it's a failed injector tip seal or a leaking pintle exhaust gasses usually begin displacing fuel in the fuel rail and causing additional cylinder misfires on the same cylinder bank.

My thought at this point is you have an injector that is on it's way out. I would either swap it as I stated or just go ahead and replace it and re-evaluate. With the limited information provided I doubt this is a base engine or electrical concern. I do not generally advise to replace the entire set of injectors unless I have proof of continuous low fuel pressure, fuel quality/contamination or extremely high mileage on the set.

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jokester00

Discussion Starter · #33 · Aug 7, 2021

Thank you all for your help. I think I'm just gonna replace it and cross my fingers, as we have a camping trip coming up in a week or so, and I can't afford to swap it out with a different cylinder and possibly have it happen again with a trailer behind me. Dang injectors only have 49k miles on them...frustrating. Pretty sure they're Alliant injectors though. I had a shop put them in not long after I bought the truck.

Again...you guys are a fantastic sounding board and the knowledge on here is priceless!

-jokester

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jokester00

Discussion Starter · #34 · Aug 7, 2021 (Edited)

Can give me a rundown of how & what you do to clean the injector cup out before installing the new injector? Want to be sure I'm doing it correctly. I assume that it shouldn't be hard if the previous one was properly sealed, right? Do I even need to brush it out, or just wipe it down with some carb cleaner and then a light coat of oil?

-jokester

Hydro

· #35 · Aug 7, 2021 (Edited)

Yeah, just wipe the cup out and run a drill bit thru the hole to get the carbon from where the tip goes
wrap some tape around the bit, so you dont drop it

A thin flat blade screw driver work well to scrape any stuck carbon, just be careful not to scratch
only really needs to be clean where the copper washer sits

Oil or Vaseline the orings just before installing -- they are silicone based so oil will make them swell some -- so lube just before
EDIT: I generally use chain saw bar oil from Tractor Supply for all assembly -- sticky non detergent oil

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bismic

· #36 · Aug 7, 2021 (Edited)

If you can get the brushes in quick enough, I would use them.

www.xtremediesel.com

Alliant AP0085 Injector Brush Kit

Check out the deal on Alliant AP0085 Injector Brush Kit at XDP

www.xtremediesel.com

Also - Rotunda Brush, Fuel Injector Sleeve.

303-D111

303-D112

The set of two is 303-DS110

Cleaning the injector bore cups - Ford Truck Enthusiasts Forums

6.0L Power Stroke Diesel - Cleaning the injector bore cups - Have the Alliant 6.0 specific bore brush kit on the way, however was curious how others use the brushes? My concern in whilst cleaning the bores, debris might somehow work it's way up into the fuel passages with the up and down action...

www.ford-trucks.com

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FordDoctor

· #37 · Aug 7, 2021 (Edited)

Those brushes are ideal but I have only needed them in cases where combustion gasses have leaked into the injector bore. I would avoid inserting screwdrivers or drills as they can easily damage sealing surfaces and the injector tip bore really does not need cleaning. My go-to method is to wrap a shop towel around a wooden dowel, spray carb cleaner or brakleen in the bore then use the dowel/rag to wipe the injector bore clean. Finish off with some compressed air. Be sure to use a bright light and inspect the bore for cleanliness and damage. Lubricating the injectors should be done with CLEAN ENGINE OIL - I install 6.0L injectors like you would a 7.3L injector, I dip them or pour clean oil on them, let the excess drip off, insert and run the hold down bolts by hand and torque to spec. Before installing be sure the hold down bolt holes are free of oil that can cause improper torqing resulting in a loose injector. I also like to install (one or all) and wait a few minutes then retorque. I haven't had any loose injector incidents since adopting that technique. Hey, even a seasoned pro can be susceptible to these pitfalls. But sometimes that is how we learn!

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jokester00

Discussion Starter · #38 · Aug 7, 2021

Sorry about all the questions, but I don't have any lint free shop rags. I do have the Scott's blue shop towels...would those be OK for wiping the cup out with carb cleaner as long as I blew the cup out with air after?

-jokester

Hydro

· #39 · Aug 8, 2021

The "blue towels" are fine

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Turk.919

· #40 · Aug 8, 2021

I’m going to have to read through this a few more times and do similar tests. My 03 does similar and I had an issue with the IPR being too tight and binding recently. Mine might be a chafed injector harness though, or an issue with the plug at the FICM

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