Ford 6.4 drive-ability

[sootie]

that you can place the oil fill cap upside down on the tube and it not get blown off.

 

[Heavywrecker]

Ok guys things I have done to the truck.....
Replaced the oil cooler
Replaced the high pressure pump
Replaced the high pressure pump harness
Replaced the frp harness under valve cover
Replaced the fuel rail pressure sensor with a genuine ford sensor
Changed tunes to a much lower setting
Added a fass lift pump(about 800 miles ago)


The truck acts almost as if there is air in the fuel system

Are these prone to getting air trapped in the fuel rails? If so how does one bleed It?

It will randomly drop to 2,000 psi or 1500 psi while cruising, slight tip in or out on the throttle and it jumps to 24,000ish or what I would call normal some times 15,000 if it's a Light tip in on the pedal.


Also does it in cruise so assuming it's not an issue with the throttle position sensor


Thanks again guys!

Sent from my SM-G950U using Tapatalk

 

[sootie]

i have seen erratic rail pressure when pcms go bad. Almost impossible to diagnose though. You shouldnt have to bleed the high pressure system. It will kill you if you get in the way of the spray.

on edit: i have to ask, why did you just throw parts at it? Seem like a waste of money to me...

 

[Heavywrecker]

No, lift pump oil cooler and pump were my decision by mileage and mods to truck. Truck has 180k on it. The truck is really screwing up now that I put that new sensor in it which makes me feel like it's air in the system

Sent from my SM-G950U using Tapatalk

 

[sootie]

if the truck is running without a miss, there isnt air in the system. We're dealing with common rail here not heui

 

[Heavywrecker]

Truck does not miss, but will drop down to 700 psi while driving and like I said light tip in or out and the frp jumps back to normal, seemed to get really bad once I changed the sensor for the 2nd time

Sent from my SM-G950U using Tapatalk

 

[Heavywrecker]

There isn't a calibration you have to do to the new pump or anything is there?

Sent from my SM-G950U using Tapatalk

 

[Lipka101]

There isn't a calibration you have to do to the new pump or anything is there?

Sent from my SM-G950U using Tapatalk

You are supposed to reset the hpfp adaptive tables


Sent from my iPhone using Tapatalk Pro

 

[Heavywrecker]

Ill swing by the shop tonight and put the Ids on it and see what happens

Sent from my SM-G950U using Tapatalk

 

[Heavywrecker]

So, fuel system high pressure wise it rite on the ball. Noticed that the exhausst back pressure sensor actual and desired are way out of wack...would this cause my drivsbility issue?

Sent from my SM-G950U using Tapatalk

 

[Roccafellas]

Firm believer in if no popped fuse #74 then no HPFP harness rub through

No popped fuse

Still chafed



Sent from my iPhone using Tapatalk

 

[Roccafellas]

Easiest thing would be to find out what the damn codes are and post them up here ...

iPhone using Tapatalk

 

[DEEZUZ]

Yea but was it killing the truck

 

[webb06]

So, fuel system high pressure wise it rite on the ball. Noticed that the exhausst back pressure sensor actual and desired are way out of wack...would this cause my drivsbility issue?

Sent from my SM-G950U using Tapatalk

Ebp-a is absolute. So you must subtract atomospheric pressure. Which is roughly 14 psi. So that puts it right at what desired is asking for.


Sent from my iPhone using Tapatalk

 

[pdaddyvr6]

I just went thru something that sounds very similar. Changed the hpfp in my truck because it would not hold pressure on a big tune. Other than that it ran fine. First drive after changining it rail pressure would get to 10-11k on easy accel and then totally stumble and fall to less than 1k. Give it more throttle and it would recover and make desired pressure no problem. F$$cked with it for a day or two , tried many things, reset adaptives, checked wiring, no air, etc. Tried resetting electrics by draining capacitors, nothing changed. Finally after some in depth data logging with ids, realized the ecm was not controlling the pump properly. Before I ordered a ecm, I figured what the hell and I pumped a totally stock tune in and took it for a drive. Ran perfectly, other than slow and lights on in the dash...........Retuned it and it ran perfectly and hasn't missed a beat. I can't explain it but whatever. Any who, worth s shot if you have not tried it.

 

[Heavywrecker]

I will try that

Sent from my SM-G950U using Tapatalk

 

[sootie]

I will try that

Sent from my SM-G950U using Tapatalk

thats what i suggested back in post 23. I have a used pcm with an H&S deleet tune flashed on it i think. You could have it for the shipping if you need one to try...

 

[pdaddyvr6]

I was not suggesting swapping the ecm. I was just suggesting flashing a factory flash into it and drive it. That's all I did. It ran perfect, other then faults for missing items. Reflashed the same tune back in it and it was fine. I had tried changing to other non stock tunes with no effect. Only after I put a factory flash in it did it solve the problem. Anyways it saved me from getting a different ecm.