Trying to help Mom-in-Law on this one...
she has an '08 F-450.
When we were out driving yesterday, she went to punch it and pass some cars, when all of the sudden, the power cut out and the truck "bogged"
I have a Turbo Diesel and this didn't feel like a bad fuel or clogged fuel filter...it was like, as soon as she floored it, it went into a limp mode of sorts...she still had power, and it still accelerated, but at less than half the power than normal.
...but it didn't throw any codes, so I am totally puzzled on this one.

At mild throttle, it drives like normal.

Any advice?
Thanks!

 

Sounds like fuel filter, or bad fuel to me. Hard to tell by your description, but it sounds like it's starving when you're wanting the extra fuel for a quick acceleration.

 

That was my initial thought, but there's no surging whatsoever, it just "cuts out", anytime I've gotten bad fuel/clogged filter, there was sputtering, surging etc. involved.

 

Power is reduced during re-gen. Maybe it's in re-gen mode? Just tossing out the idea here. If there's no CEL, Ford won't be able to help you. Try draining the frame mounted fuel filter and see if there's water, crud there. Does you mother-in-law use a fuel additive? Try the simplest things first...

 

First...thanks for the help, it's much appreciated...
No on the regen, thought of that too, she doesn't use additives, BUT...I did drain the water from the filter...and only got a tiny bit, and it stopped draining before I shut the valve back...so I assume there's blockage since my truck keeps draining until you physically shut the valve back.

 

do you know what the frp and frpv were doing when it happened or happens? also what percent the volume and flow contlol valevs were at. may be starting a hpp issue. is the truck still under 5/100, if so may be best at the dealer?

 

Is "frp" fuel-rail-pressure?
If so, no idea, truck is totally stock, no gauges.
Truck has never done this before, I was going to change the fuel filter for her first, to try to save her the shop charge for diagnosis.
If it is starting a major fuel system issue, maybe I shouldn't touch anything, though?

I do all the work on my own truck ('03 Dodge Diesel), and installed a full AirDog system when my lift pump went south, but I wasn't under warranty, and her problem doesn't feel like mine did when my pump was dying.

I'm ignorant to any inherent possible issues with the 6.4's, but she's gotten taken advantage a couple of times before on mechanical issues, so I've finally gotten her "trained" to let me know before she goes to a dealer so I can at least do some research beforehand.

...one thing I just found out is she thought she didn't have to wait to start this truck (as in didn't ever notice the wait to start light), which bothers me, it's her 2nd Diesel, and she never thought that with her old truck, but hindsight and all that...what problems would this cause over time?

Again...any help is appreciated.

 

not letting the glow plugs cycle would only cause it a longer start or perhaps a no start till it gets the cylinders time to heat up enough.

glow plugs stay on I think for up to two minutes after start if needed.

So it sounds to me like this truck no longer has a warranty? The motor is covered up to 100K with a minor deductible.

When were the fuel filters last changed? There are two, one on the eng and the one on the frame.

 

ya you may not want to start playing with the fuel system to much. customer repair price on a complete fuel system is 10-12k.

 

Alright, so I was coming up a hill when I loss power (not total) but I had the pedal to the floor and was losing speed fast and being passed by a fellow Ford driver with a 5er...sad since I wasn't towing anything that day. I get up this morning, go into town when my truck does it again . This time I was leaving a red light and i crawled at a puzzling 10 mph, but this time the "Idiot light" check engine light went on and I was sputtering along like it was starving on fuel. Shut the truck off for 30 mins or so and started it up to find the light still on. Took it into the dealer and found it was a faulty EGR valve. Apparently, those are "HOT" items failing on the 6.4L PSD these days. Dealer replaces at least once a month on a new rig which is still way less than on the 6.0. I owned the 6.0 as well and never had any problems like this one. Glad I wasn't towing my 5er at the time. I do have the Edge Juice w/attitude on it and that didn't help anything at all and it also hasn't hurt anything. Dealer was cool with it and maybe a little envious when they drove er .
Anyway, hope this helps ya out a bit. Look EGR or possibly the radiator cracking and causing "Limp mode" to come on again. Check the fluid often is what I was told. You won't notice it when it's sitting in the driveway, you have to check the bumper, left side after driving for wetness.

Good Luck!

 

i had the exact same problem my friend driving along at 80kmh for a long time went to punch it, it went into retard mode,,, wouldnt let the tranny shift unless i let off the gas was real slow to accelerate and still wouldnt go over 85kmh..

all in all i would GUESS at you still have the old EGR Valve and it is stuck open, you may want to check your degass bottle and see if you have coolant splatter under the hood i did and i still have coolant dissapering and i cant figure out were the heck it goes!!

anway good luck and i bet this is it

koboss

 

there is a new design EGR out there now, it gets rid of the coolant lines going to the EGR and I think they reroute the coolant line back into the coolers. Maybe that will help with some of the EGR failures out there.

 

I would agree, if you think you may have an EGR Valve failure get it changed out. I had some issues with my EGR Valve with similar drivability problems before it finally gave me a CEL. Thankfully the new design is holding strong with no issues.

 

This is a "smart" truck. The next time it does that, pull it over to a safe place, shut it off and restart it. If power is back until it goes into a bit of a pull, the computer is sensing that the engine can't get the fuel it requires. It then puts the fuel system in safe mode. Cycling the key switch resets the safe mode.

She likely needs new fuel filters if this is the scenario. The frame rail filter is no picnic to change, but you can do it with the proper 36mm socket and extensions.

 

with mine it would start..run rough for a min then die with a wrench on the screen no way of driving, it was to coked up

but run good now oh.. it going back to the shop sunday night for monday a list of other things that popped up.

cracked E brake cable
grill bolts missing
coolant loss
mouldings falling off
limited slip, and only have one wheel peel
thump in the right passenger side
few more things before my main warranty (free) from ford defects wares out cause after that it will cost me big..

i would sure like to know where this coolant goes... i gotta get a oil report done cause its the only place it could be going and they wont admit it.

it seems to me that they (ford) can hide more with the 6.4 than they could with the 6.0l

koboss