Hello all, this year I picked up an f350 work truck off my boss for a good price. I had to fix the primary belt and replace a tensioner on it, as well as various 4x4 components. Recently I took it up north about ~300 miles from my house and ran straight there and back with a 4 day intermittence (camping). I started the truck almost every day I was there to keep the fuel cycling, etc. Well, about halfway back after a fill up at a (peculiar) gas station, my truck started having acceleration issues. There is no codes, no oil pressure drops, the engine and trans stay at or below operating temp. The truck only throws white smoke during cold starts in the mornings (I live in Michigan, gets chilly in winter).
After digging around the forums I discovered that the fuel pressure regulator had a spring upgrade that was 'almost necessary' (or the posters proclaimed it to be), so I went ahead and did that last Friday. I changed the secondary filter today under the hood, though I still have yet to change the water separator/filter on the line under the car (won't be getting to that one until next spring likely..). After inspecting a little bit under the hood I also noticed a turbo boot from the i.c had torn (read that was pretty common on these trucks), so I replaced that as well.
I'm pretty confused as to what might be causing this without throwing a code, but obviously that's how things go with automobiles or any vehicle for that matter usually.

The most notable symptoms are delayed throttle response (will suck air in from the sound of it but will not accelerate, leads me to think it's fuel related?), loss of power, and occasionally the truck will limp along very slowly if I floor it from low speeds (~20 below). Easing on the throttle generally leads to a better response with less issues, which also further leads me to think it could be fuel pump related. I've never owned a turbo vehicle or a diesel, but from what I've read this could be turbo related as apparently the vanes often get stuck on these trucks often. Oddly though the turbo spools fine and responds great to pressure buildup, the only odd noises I will usually hear from it are the 'cha cha cha' after cutting throttle completely from high rpms.

I've also read about the egr causing these issues but I unplugged the sensor and the problems persisted the same without any change. Understandably the valve itself might be clogged or dirty, but my bets are off on that one (though I will check if prompted further to on this discussion). Yet the truck also has no white smoke issues or flowing fluid from the exhaust, leading me to conclude it's not egr cooler related and unlikely egr period.

Last note, our property is on a hill which I had to, well, basically race up a few times which shook the truck pretty good (went over about 3-4 feet of snow spots, etc). Also, to fix the 4x4 I had to pull all the fuses to single out any wiring issues. I replaced them but maybe one came loose? Anyone know which ones could be causing issues related to fuel or air sensors and the like?

Any thoughts on where to look next? Maybe the map sensor could be causing issues with the fuel ratio? Let me know if anyone has any ideas. I might mess around with the map after posting this, will update if I get around to it.
Thanks in advance guys

 

What are you using to check for codes?

 

Could you have received some water at that last fuel up ?

 

I'm wondering why the wait until Spring on the primary fuel filter. It is the one that will take the biggest hit with bad fuel!

They should be changed together IMO. At 10k-15k mile intervals, and with OEM fuel filters.

 

So am update, this morning I went ahead and did the primary fuel filter (was waiting for it to stop snowing, luckily I got a chance today). I also cleaned the egr valve and the cac tube along with the hoses. There is no cracks or breaks in the hot side hoses, have not yet checked anything on the cold side or air intake related. The truck is now throwing black smoke and stuttering along occasionally, leading me to think it might be airflow related instead of fuel. It also is barely able to make it up my driveway most of the time it's running. When I throw it in neutral or park it seems to idle/run better, but still very rough and sometimes will even die on me. Could this be sticking turbo vanes? Would dread digging that deep into the engine so soon after buying the vehicle but that's life I suppose lol

 

Have you checked the air filter minder?

Again - what are you using to check for codes. Not all scan tools are created equal and definitely tuners that can retrieve SOME engine data are not good at retrieving codes..

 

I have a generic scanner from harbor freight or somewhere I bought it from a while back, nothing special or fancy. Understandably it can't read all the codes, I'd rather not take it to a dealer if I can avoid it.
I pulled the air filter after looking at the minder and it was dry, not overly filthy but I'll still be replacing it. There's now less black smoke but probably because it's barely staying running. I took it for another test drive and it died on me, took about 4 mins of intermittent cranking to get it running again and back home. It slowly died down to a very slow rpm, was not sudden. Checked all the hoses to turbo and pipes as well as visually inspected the down pipe as best I could, could not see or feel any cracks/tears. Is there a valve to check fuel pressure on this truck? If so, does it require any special adapter? I have a gauge for f.p and I'd like to rule that out if I can.

Also it runs very good for a few minutes and goes back to running terrible or dying, and then repeats. I am almost wondering if I might have a really bad tank of diesel?

 

No need to take it to a dealership .................

ForScan Light on a smartphone reads codes as well as anything you can use. #6 download. $35 for the ELM32 IBDII adapter (get the appropriate one for your device). The BAFX adapters are inexpensive and they work. Lots of people would rather change parts than troubleshoot. That said, there are no guarantees that there are codes, but I have done this for a long time and the majority of the time, codes help track down the issue,

 

There is a fuel pressure test port on the side of the secondary fuel filter, by the regulator.

M12x1.5 to 1/8" NPT fitting

 

Closely inspect the VGT connector and its wiring.