After 106,000 troublefree miles our 2004 6.0 has developed its first issue. About half the time when taking off from a stop we get what feels like an engine not responding to the accelerator pedal. When this happens black smoke rolls out of the tailpipe, keep fiddling with the pedal and then it will take off, run great and the smoke clears up. No check engine light is displayed. Ideas to check???

 

Egr valve.

 

Just like he said. It's probably stuck because of all the #@$!@ built up on it in the last 106K.

 

Look at the wiring on the pedal very carefully for chaffing. We had this and it wound up being this and another problem, Chaffing on the engine harness, we had this a couple of years ago. With both harness replacement it took the teck 3 days.

 

Ok assuming its a stuck open EGR valve, then we are getting the fuel when I step on the accelerator but since the intake manifold is delivering too much recirculated exhaust it can't burn properly which is why we get all the black smoke and the bus won't accelerate? Has this ever been resolved by just running the tar out of it or is it simply time for a new valve and cleanup of passages.

 

Having looked at mine at 30k and finding a very sticky mess - You can be sure that it will not clean up by driving differently. I replaced mine at 30k and will pull it again at 60k to see what I have.

The ccv reroute mod is highly recommended to alleviate a big part of the problem.

The wire chaffing that bigredtruckmi suggested is easy to check - pictures of where to look have been posted before (an easy search topic). Even so, I agree w/ brickie and dcaddi2 that the most likely culprit is the EGR valve. You should definitely pull it and see what it looks like - and be prepared to have to pull hard (and have a new one on hand).

Good luck

 

My 04 did the exact same thing and it turned out to be the turbo veins sticking. As the engine built up a little exhaust pressure to turn the turbo it would slam the veins open, smoke like a tractor and take off like a raped ape. Congrats on hitting that many miles and no troubles.

 

If it is the egr valve just weld it shut and weld bypass plate in there and be done with it.

 

Update; Local dealer had an EGR valve on hand for $350 list- $260 wholesale. So I set about to remove the old one, but first since its an E450 I had to remove a bunch of pieces before I could even see it. I now have seen parts of this engine for the first time. If I would have had a reman alternator on hand I would have swapped it out while I was in there. At any rate I managed to coax the EGR valve out of there by turning it slightly and then using one end of an open end 15/16" wrench as sort of a rolling head pry bar while I worked it has much as I could in the tight quarters. The valve really did not look too crusty and the soot was dry, I would imagine most of these valves (or modulators as Ford calls it) would look the same after only a few thoasand miles. The only evidence of an issue with this valve is that you can see about a 1/32" ring of light around the seats, of course it could have been hung open farther before all the jostling to get it out. New valve is in and tomorrow we will get all the parts I had to move or remove back in place and go for a road test.
Thanks for the responces, ideas and help! If this solves the problem I just might be so moved as to finally become a supporter

 

Are egr valves that expensive to replace?!
also, good to hear a 100K'er w/ no probs.

 

I believe I paid 260 for mine from the dealership

 

Well we ran it about 250 miles today and no issues so it would seem the EGR valve replacement took care of the problem.
The cost of being a supporter pales in comparison to what I saved in time and money on this issue with input from this forum, so I am in, not sure how long it will take to show by my name.

 

Glad it solved your problem! Good luck on the next 100k.

(my next guess was going to be too much oil ........... :-) )

 

Hey, I could have spilled my coffee.. ;-)

 

Your problem is mirroring what I'm seeing in my 06 F250 4wd 6.0 with 35,000 miles. Glad to hear it fixed your issue, and Sorry to hear that part cost so much.

I have a Ford bumper to bumper extended warranty to 100,000 miles, so do you guys think this repair would be covered under that scenario? It's a $100 deductible per visit, and I have yet to take it in...