Hi, long time member/lurker; first time poster. I've searched a ton of threads over many forums without finding much luck, so I'm going to go ahead and ask here...

Brief history: 2003 Excursion 4x4 6.0, bought in March of 2016 with 174K miles. One "real" owner truck, and I was told lady driven and never used to tow, etc... Truck was bought by local Diesel mechanic, cab pulled, new heads, gaskets, studs, EGR delete, 4"back cat delete, blue spring, billet hpop and then sold to me... Mechanic has great reputation and I was happy with the purchase. Bought an edge insight after the first month and noticed the FICM volts were low at startup, so I bought a new FICM from Ed and it's been a steady 48 since. Truck is tuned with SCT canned tune (performance)

I had driven the truck mostly to work and back (around 20 miles) with about 6 roundtrips of 400 miles with no issues. In June of 17, I drove about 90 miles to Charlotte when the following issue happened.

I started getting a miss at highway speed about 50 miles into the trip. It got to the point tht the truck would no longer build boost, or even move under it's own power, would shake like crazy, then shut off. I got multiple cylinder contribution codes from both banks, and the truck wouldn't immediately restart. After about 10 minutes of sitting on the side of the hwy, truck starts again, and I continue on my trip... 5 miles later, same problems as before. I limp the truck to Charlotte (I know, bad idea, but this was an important trip) and park it overnight.

The following morning, truck starts and drives fine until reaching Operating temp (about 190 Oil temp; Coolant around 184), Then I get the same problems. Tried to get home, but truck would only drive about 5 miles before having to stop for 20 minutes to cool down. I had my young kids with me, so I called the tow truck.

The day after that, I drove on the highway close to the house for about an hour with zero issues. I'm really puzzled now, and I was starting to think that it might be engine load related somehow since I live in a flat area, and the route to Charlotte has a few medium hills. In short, I couldn't duplicate the problem. I felt some cracking of the wire loom on the injector harness and saw some wires exposed, so I changed it out with a new motorcraft harness. The wires were exposed, but not bare in any places. Fast forward to September, and the truck randomly starts the same issue as stated above on my flat route to work.

Limped the truck to the shop I bought it from. Under new ownership, but the tech that had done a portion of the work on my Ex now owns it. He's puzzled, but finally arrives to a bad fuel pump and I have it replaced (kept a motorcraft). Things are great again, no issues, and I haven't had to go out of town since then.

Last weekend, on a trip to Raleigh, the same issues popped up... I guess it wasn't the fuel pump after all. Finally tonight, It happened on my ride home from work.

This is my first diesel, and I'm somewhat mechanically inclined, but I'm just wondering what you guys might have done if you've experienced anything like this. Also, I did the fuel-bowl test for air in the lines, and I wanted to run something by you. All the youtube videos I saw have this test done with the bowl FULL of diesel. My bowl won't hold fuel above the very bottom of the threads, about an inch from the top. I know it's impossible to diagnose over the computer, but I'm hoping that someone just might have SOMETHING I could check.

Thanks for reading my wall of text!

 

Question, was the tack jumping around when it happened.

 

It sure was shaking, almost like riding over some really bad pavement. It wasn't surging or anything like that... It just got slower and slower until it finally stopped.

 

You pull any codes, like cam crank sensor

 

Sometimes, I get cam and crank sensor codes. This morning, I got about 5 miles down the road before it started messing up. Taking it to a different mechanic later this morning.

Anyone know if my upper fuel bowl should be holding fuel to the top with the cap off, or is it dropping down to about half full after about 30 seconds with some big bubbles right?

 

You should not ever see bubbles in the fuel system

 

Your symptoms sound exactly like what I experienced in the beginning of January, and there's a 7-page thread entitled "5 injectors later & still has highway speed shudder". You may want to read through it if you haven't already.

In short, I discovered a low fuel pressure issue and made some pretty good headway on it but still suspect an issue with FP under WOT that I will probably get back on soon. I'm in the process of completing some high speed highway test runs to see if I have this licked because as you are experiencing the issue doesn't rear its head every time you drive. In my case, the truck won't exhibit the symptom unless I'm doing about 78 MPH via cruise control.

Please update us if your technician finds the root cause as I've found more than a few threads here in recent history with similar symptoms and no one as of yet has reported back a final fix, which would be helpful to the community.

 

Are you pulling the filter out when you say "the fuel is not all the way full"?
The filter has some fuel in it obviously, with that said can you see the level actually decrease with the cap off? Or is it that far down once you remove the cap?

The other thing I am wondering is are you running at 1/4 or less on the fuel gauge?
These trucks are known for tank pick up tube issues.

 

Yes, the filter is out. I can cycle the key on and watch it fill up (to overflowing if I don't cycle off) Then, it takes about 30 seconds to drain halfway. I can see large air bubbles every now and then while it's emptying.

 

I'll check that thread. Brand new fuel pump helped me for about 4 months. I'll close this thread when fixed or I sell it out of frustration.

 

Sounds to me like it's fuel delivery and not necessarily related to bad injectors, etc since you are not doing the bubble test.
You are getting bubbles but seems to be related to air entrapment somewhere.
Let some other folks chime in, I'm not well versed in the upper fuel bowl as to what causes it to drain like that, but I don't think it's time to put this truck out to pasture
Might be something as simple as the o ring on the seat or the plunger under the regulator cover.It's an early build so will have both.

 

I am even less versed in upper fuel bowl characteristics and therefore don't know if the bowl draining described above is normal or not, but as it drains wouldn't it be typical to see the occasional bubble as the fuel makes its way back down the return side of the system? I suppose we need to ask the OP for clarification on exactly what he's seeing, but his description makes it sound like he's only seeing a bubble every now and then which doesn't necessarily sound like a problem.

Again, I claim ignorance on this area of the fuel system as far as what should be seen when watching that upper bowl so my comments are offered up as an opportunity for me to learn something here.

 

The way I'm thinking is there shouldn't be any air in the fuel system at all to cause these bubbles - even on the return side. I am no expert on it either though.

 

Dropped it off with the mechanics today. Drove to work this morning and didn't make it 5 miles before the shuddering. EOT was at 135 degrees this time. Limped it home and drove the 9 miles to the shop with absolutely zero issues. Waited on my ride, and the techs couldn't duplicate the problem while I was there. More to follow.

 

Thank you for the update. I am curious what they find. Not sure if you checked out my thread yet, but after some trial and error I discovered that I erroneously didn't install an o-ring in the fuel pressure regulator when I originally did the blue spring upgrade 7 years ago. Adding that o-ring along with a fresh spring got me good fuel pressure at idle and moderate driving speeds. I'm still not happy with WOT pressure so I'll be watching to see what is found on your truck.