Fuel rail fluctuations. P0087, P2291

bigfords

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Hey guys got a 6.4 that I'm a little stumped on. Wondering if anybody has any input.
2008 6.4 that would fall on its face on first acceleration, rail pressure would drop to 1200psi and then bounce back to the commanded 8,000psi after a second or two. Had codes P0087 and P2291. Otherwise truck ran well, and is a bit smokey.
Replaced HPFP, LPFP, Fuel rail pressure sensor and under valve cover harness.
Got truck back together and truck is doing the same thing, but possibly worse.
Now the fuel rail pressure fluctuates from 3,000-6,000 psi at idle.
Truck still falls on its face on first acceleration, stumbles, then rail pressure jumps back up where its supposed to. PCV valve seems to be what is fluctuating causing the issues.
Any ideas what could be my issue? Truck is ******d and tuned, (H&S).

thanks!
 

kleake

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Is it right after a shift point? Mine does that until it fully learns the shifts, then it's fine after that.

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bigfords

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No, not after a shift. It does it whenever, mostly on the first acceleration after a decent idle.
 

TRUBBS

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I’m fighting this EXACT same issue, I’ve checked just about anything and am loosing my mind.

Did you ever find a fix?
 

jordysoso

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I agree with sootie, send the injectors out and get them tested. If fuel pumps have been replaced, filters aren't clogged, and you're still getting fuel flow the only thing left in the succession is injectors.
 

TRUBBS

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I actually found my issue as a last ditch hailmarry after everything in fords pinpoint diagnosis turned up nothing, and no one I talked to could think of anything else to look at. and could be your guys issue as well,
Ford had an updated calibration/configuration at some point during the run on the 6.4, this truck I was working on never had been back to the dealer for work so it never got the update.
I had them update this truck to the latest & greatest files (had an update for the PCM & TCM) and bam problem was fixed.

I tried everything before, Swapped HP pumps again to make sure I didn’t get a bad one, swapped LP, Rail sensor, Downloaded a new H&S PCM recovery file my buddy has from back when they were open ext.. and nothing worked to fix it, till I had the pcm updated & BAM problem was gone!


I know how frustrating this can be as I fought it for weeks and lost my @$$ on doing it, I searched everywhere & talked to anyone who I felt could offer valuable advice and never could find a fix. So hopefully this helps someone else who’s struggling to find a fix.
 
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sootie

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I actually found my issue as a last ditch hailmarry after everything in fords pinpoint diagnosis turned up nothing, and no one I talked to could think of anything else to look at. and could be your guys issue as well,
Ford had an updated calibration/configuration at some point during the run on the 6.4, this truck I was working on never had been back to the dealer for work so it never got the update.
I had them update this truck to the latest & greatest files (had an update for the PCM & TCM) and bam problem was fixed.

I tried everything before, Swapped HP pumps again to make sure I didn’t get a bad one, swapped LP, Rail sensor, Downloaded a new H&S PCM recovery file my buddy has from back when they were open ext.. and nothing worked to fix it, till I had the pcm updated & BAM problem was gone!



I know how frustrating this can be as I fought it for weeks and lost my @$$ on doing it, I searched everywhere & talked to anyone who I felt could offer valuable advice and never could find a fix. So hopefully this helps someone else who’s struggling to find a fix.

was this on a stock or tuned truck. if tuned, what platform?
 

Ldilella1

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I actually found my issue as a last ditch hailmarry after everything in fords pinpoint diagnosis turned up nothing, and no one I talked to could think of anything else to look at. and could be your guys issue as well,
Ford had an updated calibration/configuration at some point during the run on the 6.4, this truck I was working on never had been back to the dealer for work so it never got the update.
I had them update this truck to the latest & greatest files (had an update for the PCM & TCM) and bam problem was fixed.

I tried everything before, Swapped HP pumps again to make sure I didn’t get a bad one, swapped LP, Rail sensor, Downloaded a new H&S PCM recovery file my buddy has from back when they were open ext.. and nothing worked to fix it, till I had the pcm updated & BAM problem was gone!


I know how frustrating this can be as I fought it for weeks and lost my @$$ on doing it, I searched everywhere & talked to anyone who I felt could offer valuable advice and never could find a fix. So hopefully this helps someone else who’s struggling to find a fix.
 

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