Need a 6.4 guru!

option2

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Ok so recently my 08 job 3 f250 went into a local diesel shop for a cab off HPFP and an elite diesel 72.4mm l.p. turbo, while in there the passenger side up pipe was found to be leaking so that was replaced with a factory ford one. The truck is fully ******d so the egr pipe was cut down and modified to relocate the EBP sensor up top. Well long story short after everything is done I go to pick it up after the mechanic test drove it. I turned out of the parking lot and EASED in to the go pedal, at about 15-20% throttle it falls flat on its face with rail pressure down as low as 200psi.

I let off the throttle and smashed it to the floor so I could get out of traffics way and it cleared up, FRP went to 24k+ and i burned a thousand miles off my rear tires. I returned to the shop and he hooked a scan tool up, the only thing thst seems to be way out of whack is the Mass Air sensor, putting the truck in gear and loading the engine the truck thinks it's pulling in over 600g/s of air when 100-200 Is expected. We pulled the black maxx and returned it to stock programming, had a new sensor ran over from ford and none of that changed anything at all, even updated my h&s files.

Since then I've been out on my drilling rig working but he called the other day to update me, he said he got a hold of a used COM from another 6.4, he tried a different new MAF sensor and ran what he called wire overlays to eliminate a problem in the sensor wiring(seems a bit far fetched to me when itd be much easier to just test each wire and compare readings but so far NOTHING has made a difference let alone fix it, I'm losing sleep over it and he's pulling his hair out over the canned thing, i HAVE to have this truck up and reliable by snowfall or I'm screwed, any help or ideas no matter how crazy are appreciated! Oh yea truck just turned 100k miles, s&B intake full sinister ****** with elbow, mbrp 4in dp to 5in straight pipe, h&s black maxx running canned hd300 tunes, brand new Alliant Power k16 and brand new elite 72.4mm atmospheric turbo
 

sootie

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the engine wouldnt run with rail pressure as low as 200 psi. Did it happen to be at a shift when it happened? If it was just retuned it could be the trans trying to relearn. Has anyone got it to repeat the problem?
 

option2

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The black maxx drops to .3, asnd it def doesn't seedm to be running but if you lay it to the floor for a few seconds the truck will come alive and burn the rear tires off. Dec not during a gear change, it happens almost the second you let off the brakes and hit the pedal...EVERY time. I've been doing some reading and 600 grams of air is regular for an H and s tuned truck, i think the tech is looking I'm the wrong places kinda curious what the EBP is reading along with each injector
 

option2

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Sorry for all the damn spelling mistakes, just swapped to the new galaxy from an iPhone and it's killing me
 

78f100

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as already said the truck would stall at 200 psi rail pressure. First I would look hard at the ebp and harness to it, they are bad about the wires breaking under the insulation right at the plug. Ford has a new pigtail for the connector. What is rp at idle?
 

option2

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I just stopped by the shop and the ebp/baro/mass all correlate perfect. The damn thing throws a persistent p0102 mass code, tried 3 different sensors, a different PCM and overlayed wires to eliminate a short or break in the wiring to the sensor. We're basically to the point of pulling the black maxx out, putting the factory tune back then bringing it go ford for reprogramming/updating. I don't believe the trucks been updated in years, I'd love to say I have confidence that that will solve the issue but I'd be lying.

Edit: rail pressure at idle is 4800-5200, this problem occurred 25 miles after having the cab off for the new Alliant pump and elite turbo, it's getting constant fuel from the FASS as well so it's not a lpfp problem
 
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sootie

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Taking it to Ford is a waste of time. When you tune a truck, it replaces the stock flash anyway (whatever updates you get will be gone as soon as you flash the truck again). Also, if you swapped the PCM with no change, it isnt a PCM issue!!

I never understand why people always blame tuning first, when it is almost never the issue.
 
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FRP sensor..

FPR on pump...

FCV on pump...

HIGH back leak on injector...

low or poor lift pump pressure...

I feel it needs a pump as it sounds like the pressure reg went bad.
But try FRP sensor first . let truck get up to running temp then test . if truck fails after warm then I would say pump reg. Good luck.

GET IT TO SOMEONE QUALIFIED TO DO SUCH A DIAGNOSIS. sorry

Things like these kinds of problems are not a simple yes or no you have to understand data across the data stream to diagnose a problem like this...
 

95GTSpeedDemon

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^These guys are steering you correctly. If it was trans relearn doing weird stuff, it mostly would be shift performance, likely not causing a bog, but the pcm does have total control. Also it would be right after the work was done or programming, not 25mi later.
Take a look at app (accelerator pedal) voltages (more than one pid) and see if its reading right. Truck cant do what its asked of you if it cant see it.
Where is the truck located?

Sent from my LG-E980 using Tapatalk
 

option2

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The pump is a brand new Alliant Power, I know its possible to get a bad one out of the box but unlikely(well maybe not considering my luck). The acc pedal was something I brought up right away and it's something they're going to look into, the MAIN reason it's going to ford is so they can do more in-depth injector diagnosis, I dont think it's tuning because it moved like a raped ape for 30,000miles. Damn thing would smoke my 02 vette to 80 from a dig no problem, also the trucks up in central ND
 
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The pump is a brand new Alliant Power, I know its possible to get a bad one out of the box but unlikely(well maybe not considering my luck). The acc pedal was something I brought up right away and it's something they're going to look into, the MAIN reason it's going to ford is so they can do more in-depth injector diagnosis, I dont think it's tuning because it moved like a raped ape for 30,000miles. Damn thing would smoke my 02 vette to 80 from a dig no problem, also the trucks up in central ND

It is very possible. For reasons I am not disclosing as to avoid Dick swinging contest . But... this is a very good thing to consider. Hope you find better luck.
 

95GTSpeedDemon

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Desired vs actual makes a big difference. If it reads higher than actual it wont set a code but will run bad. Same for reading lower than actual. A good ford tech who knows what the stock pressures are suppose to be and knows its modified for more pressure will have a better time at finding the root cause.

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option2

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Well I drove the truck over to the local Super Duty center the other morning, it was chilly out maybe 45*f and the truck ran almost flawless, no falling on it's face at tip in on the throttle, it was initially on a 75hp time so I figured what the hell and turned it up to a canned 300 tune, turned off TC and punched it at 45-50 and she broke the rear tires lose and slid sideways no problem, I had ONE very minor fluctuation in RP just as I was pulling into ford but nothing like it was before if that helps you guys, the lift pump is pushing constant 6psi under load, lowest we saw when loading up the engine was 4.8 psi which is within factory specs, I think if i swap in new filters on the FASS that will probably go up a little more even, also considering adding a sump to help with fuel and for future goals when I have dual pumps, waiting on all that until I buy a new 6.7 for a daily driver though
 

option2

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UPDATE


Ford has had the cab up and down 5 times in the last 10 months, its NOT the hpfp, we tried 3 so it's been a very expensive deal with no one wanting to take any responsibility. I finally had my lawyer call and now they seem to be in a helluva hurry to figure it out. My theory is that one of my injectors is failing open to the return side and dropping my RP down the ****ter, it's about the only damn thing we haven't completely swapped out or changed but the "best" mechanic around that's working on it claims its absolutely not that because hes looked at them but I haven't been billed for new headlines from God Rail to injector so I know hes full of ****, I'm almost 15k$ I to this dsmn thing, anyone have any insight?
 

Jsexton

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WELCOME TO A 6.4... IVE OPEN MINE UP TO SOME FUN STUFF NOTHING MAJIOR AND NOW ITS ONE ISSUE AFTER THE NEXT... IVE LEARNED ON MINE IF I CAN'T DO IT THE HELL WITH IT CAUSE IF I TAKE IT SOME WERE ALL ISM DOING IS PAYING SOME ONE TO TEAR IT UP EVEN MORE...ANYWAYS I FEEL YOU PAIN
 

BOSS450

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WELCOME TO A 6.4... IVE OPEN MINE UP TO SOME FUN STUFF NOTHING MAJIOR AND NOW ITS ONE ISSUE AFTER THE NEXT... IVE LEARNED ON MINE IF I CAN'T DO IT THE HELL WITH IT CAUSE IF I TAKE IT SOME WERE ALL ISM DOING IS PAYING SOME ONE TO TEAR IT UP EVEN MORE...ANYWAYS I FEEL YOU PAIN

Why are you yelling
 

option2

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I wish someone some input, I'm thinking it's been an injector the whole time and the new pump just added that much more stress to it and caused it to fail, its not smoking or showing any signs of a hg or piston issue, I just dont understand how its taken 10 damn months and this much money and no answers🤔 blows my mind
 

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