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Discussion Starter · #1 ·
Having a intermittent problem that's driving me nuts. Its happened 3-4x in about 3 months. Its always a cold motor issue. Truck starts fine, fires right up. I usually warm it till about 170° before driving. Right about the 120-150° range the idle drops, gets really rough, almost lopping. Zero power. Truck won't even move under its power. Black smoke when throttle is applied. But once it hits 180ish°, shut it off and restart it and its totally fine.

The other day it wouldn't start, killed the batts trying. It would almost catch, than stumble. Finally got it started, but it was right into its rough idle mode until warm, cycle the motor and no problems.

170k
Studded and deleted
Ficm 47-47.5 will show 46.5 for a split second
Hoop is 700-800 at idle
Fresh motorcraft filters
Amoil
Archoil
Twc3
Batts are fine, load test OK

Ideas? What to look for?
ICP sensor?
Ficm shorting some how but still at 47v?
 

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An FICM can show good voltage and still be bad. That's not a definitive test. Unfortunately there is no way to definitively test and FICM for the average guy. I would call Ed at FICMRepair.com - FORD Powerstroke 6.0 FICM Repair, PHP Tuning and Truck Parts and ask him his thoughts on your symptoms.

Unless you are seeing a pressure drop at the ICP, then I don't think this is your issue. If its HPO system related you'll see a pressure drop at the ICP followed by a duty cycle increase on the IPR.
 

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What do your fuel filters look like?
Last time you drained the separator?
Have you .jiggled the ipr wires? (They like to chaffe in that heat shield sleeve)
Checked ficm connections?(like to come unplugged)
 

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Discussion Starter · #6 ·
Filters are good
IPC is good
Hpop shows 500-2900 depending on throttle
Checked the ficm wires.
Wiggled everything.

Wondering if its not an injector sticking open? Or really bad stiction?

Every day since ive posted this its run absolutely fine.
 

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Injector stiction would be worst cold, when the oil is thickest. It still sounds like an FICM issue to me, because this is what electronic problems do; they are intermittent, and when you try to diagnose it the problem won't repeat.

What year is the truck?
 

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Check your IPR screen for damage. It could be a failing IPR. It could also be a bad ICP. You could try unplugging the ICP and see if the problem persists. Being an '05 likely rules out an issue with the HPOP.
 

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Discussion Starter · #10 ·
I did unplug the IPC while it was doing it, the rough idle sequence, and the idle really didn't change. It kinda changed speeds for a split sec, but then right back to it.
 

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The change was just the PCM switching from a read value to an inferred strategy when it lost the signal from the ICP. Check the IPR.
 

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Unfortunately, none that I know of. You can connect it to 12V power and listen for a click, but IPRs that don't click have been found to be good, so it isn't definitive.

I would check the screen for damage though.

Also, do you have a way to read IPR commanded and ICP while its doing this?
 

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Discussion Starter · #14 ·
Unfortunately, none that I know of. You can connect it to 12V power and listen for a click, but IPRs that don't click have been found to be good, so it isn't definitive.

I would check the screen for damage though.

Also, do you have a way to read IPR commanded and ICP while its doing this?
Ive got a SCT x4. It will read the ICP, but not sure about the IPR.
 

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From what I've read the X4 cannot read IPR value. Its to the point where some data would really help, because otherwise you're going to be taking shots in the dark, expensive shots. At this point you should either take it to someone who has the ability to read everything, or buy a diagnostic like Auto Enginuity so you can do it yourself. The cost of AE will probably be recouped the first time you use it instead of having to take the truck to a shop.
 

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Not sure, its not something I have direct experience with, but you should be able to check which PIDs it will read.
 

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Discussion Starter · #18 ·
It hasn't done it since I started this thread. Shows how intermittent it is.

I have been cycling the glow plugs and letting all the injectors cycle and then stop 3xs before each start. Dunno I'd thats doing anything. Its going to be 15-18 here in the am. I also added revx yesterday.

I'm still thinking ficm problem on the logic side, it literally sounds like its running on 3 cylinders when it does it. But no codes, ever.
 

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Your start up ritual is what I used to have to do when my FICM was going south. But, you usually get codes with a failing FICM, though they can be intermittent too. I used to get a P0606. It threw that code four times in an hour once, and then didn't throw it for a month. The diagnostics are only so good.
 
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