Constant limp mode, Please help
 

Hey guys,
This is my first post, though I have been following the forum religiously since I bout my 08' 6.4 dsl F350 SRW a few months back. My truck is running great, however my buddy bought a similar truck with 105k and he has had noting but issues with it. So, to be a good friend and so I know what to do when my truck has these symptoms I'm asking for help.

Heres the deal the truck constantly falls into Limp Mode and then he shuts it down for 5 min or so then it comes right back and runs great. 20 - 100 miles later it falls back into limp mode. We took it to a local Dsl Tech and he said he doesn't think it's the HPFP because it runs fine sometimes, but couldn't give us an answer as to what it might be. Given the info what do you guys think? Any suggestions It mostly falls into limp after climbing a grade or getting warm.

Diagnostics:
P0087
Lood- 56.8%
ECT- 176
MAP- 38.3
RPM- 1413
V Speed- ??? said 5mph, I was going 60mph?
IAT- 114 deg.
MAF- 42.488
PTO- ON
Run time - 240 sec
Fuel Pressure- 3285
Command EGR- 2.3 %

P1780:
EGR Error- 21%
Fuel Level- 12.9 gal, was reading 3/4
Warm Up DTC CLR - 14
Clear distance 146 miles
BARO ( in hg) 27.1
CAT " 258.9
CAT-12- 233.2
ECU Volts- 13.552
ACC. Pedal D&E - 12.5 %

P0087 X X Fuel Rail/System
Pressure - Too Low
This error will be set if the fuel pressure in the rail is too
low and the controller cannot regulate it to the setpoint.
20 % “overposition” of the
PCV or VCV [% PWM]
5% deviation of the fuel rail pressure
to the fuel rail pressure setpoint.
Low pressure system, wiring to
VCV and PCV, FUP sensor, pump

Based upon that code it is either a wiring, low pressure pump (down on the frame rail) or the HPFP (VCV is integrated).

Suggest two things for him. First make sure to do a filter change right now. Motorcraft filters only. When changing the engine mounted filter look into the fuel bowl. Ensure it is nice and clean and rust.

Secondly drain that fuel water separator and make sure there is no water in there at all.

Take the truck in for proper diagnostics. Hope there is still warranty on this truck.

I am thinking you will need it.

Ok thanks, I'll tell him what you said. Unfortunately, the truck is out of warranty. Why Motorcraft Filters? Some say it doesn't matter while others, like yourself only recommend Motorcraft. Is it just preference?

Because they fit properly.

Great! Thanks again.

My 2008 6.4 with 120,000 miles is a piece of s--- just like the rest of 6.4. I've had nothing but problems. Now it's stuck in limp mode and I can't figure out what it is. Diesel techs at the dealer don't know s--- either. I will never in my life buy another one.

Sorry to hear that, my buddy's truck ended up needing a new hpfp and now it runs like a top. The 6.4 is the best diesel I've owned.

You should start your own thread and give us all the info you have on it so we can help.

Your lucky, I've put probly 4k into it in last year. It needs more but I can't afford to keep fixing it everyday.any ideas on y it's stuck in limp mode?

Translate what HPFP is plaese to a new 6.4 owner i cant follow all the abbreviations yet.

I'm guessing it means high pressure fuel pump

Iam all set high pressure fule pump. I had to replace on my sea ray bow rider.

Thanks o8powerjoke It sounds like your not to happy with 6.4 Ijust got mine and i dont want to feel like i have to cross my fingers to use it. hope all works out for you.

Thanks I hope u don't have problems. I had to delete dpf cause it clogged completely,so I also had to get a tuner so I chose sct tuner, just replaced egr valve, had to replace radiator which is $900 dealer only. It's every week I have to put 100 here or 300 there into it, it's pitiful.

Yes HPFP is high pressure fuel pump.