To the ford techs, I have taken my F550 to 7 diferent dealerships to address problems/issues on my 6.4. You tell me what you think of some of these answers and if these are "qualifed" personel.

I have gotten BS rangng on why my MPGs are so bad from the trucks to heavy (The truck weights 12.5K loaded, 11.5 empty on a 19K truck), The rears are too steep I should have gotten faster rears, (their 4.30's the fastest ford offers), The engine is detuned from the F250-350's/ the engines are all the same (either they are different or they are the same, it can't be both), The trans in the F250-350s are geared different/ the same as in the F450-550's ( again they are different or the same , can't be both), Big trucks just get bad MPGs (then why does my buddies 80K loaded kenworth get 2 mpgs better than my 13K Ford) (thier answer to that, is kenworth designs their trucks that way with gears Ford can't figure out how to gear a truck?), The box has too much wind resistance, (It's smaller than a standard box body or plumbers body that goes on the F350 and tons less area than the Kwoper), faster rears won't make a difference in MPG's ( if I run 15% less RPM's how can I not use less fuel at the same speed, especially if the engines/trans is the same as the F350 which comes with 3.73's and is rated for my current weight), The cab and chasis weighs 6K total (then why does mine weight 11.5K with a 1.5k body on it empty, where did the other 4K come from)

I can keep going with the BS I have gotten. Like ford plans to keep the 6.4 for years, (then why are they designing the new motor, and as I understand it this one will not meet 2010 emmisions standards, so how can they keep using it?) This one came from the dealer in the western part of the state that sold me my truck and told me I would be getting 13-15mpgs no problem ( not the 8 I get) His answer to my mpg issue, I should have gotten an F650-750 with the CAT motor, they get 12-14mpg. (yeah thats what I need to haul 1.5k of body and 1-2K of tools, a truck that requires a CDL and has air brakes as a DD.)

The most BS has come from 3 dealers that are supposed to be TRUCK dealers that sell F450-F750's. I might understand the BS from someone selling F150's but not someone who sells real trucks.

I had to drive 40 miles one way to get a dealer to even attempt to LOOK at the truck in the shop. They did correct some minor issues and reflash the comp. That service manager did mention that my truck was in the group that has had radiator and other issues and to moniter the truck. No other dealer would even say anything about that. He stoped just short of saying I was being lied to by other dealers, and one tech told me there are reasons I can not get the tech info on the motor / trans that I am asking for, but wouldn't say anything else. make you wonder don't it.

Mine is starting to signs of soot now also. This is what I have found from other sites.

http://www.forddoctorsdts.com/articl...icle-07-03.php
look at the failures section.

I thought I saw the TSB on this, but can not find it now that I want to look at it. I would apreciate it if one of you techs can post the info. I'm getting tired of this game Ford seems to be playing with the 6.4.

 

Soot in the tail pipe means a defective DPF. That is the whole reason for the DPF....no soot emmissions.It also may not throw a code, Mine did not. Your local Service folks may not be up to speed. Go to a higher level. We had no problem ..one look at our black tail pipe and the dealer ordered a new DPF.

 

Gears actually really seem to effect the 6.4s mileage. But your right in that you couldn't have gotten faster gears then that

The F450/550s have a detuned 6.4, its at 310 or 325 HP (I forgot which), vs. the F250/350s 350HP

The reason your mileage is so poor is because the DPF requires extra fuel to raise exhaust temperatures to burn off all the soot it collects, and your 4.30 gears

That could also be hurting your mileage.

Also, why do you have an F-550 if you are only hauling 1-2k in tools?

 

This is part of the problem out there. A DPF fails for some reason. Generally, its brought on because of excessive heat. Why is there too much heat? Just replacing a dpf and doing nothing else doesn't fix anything. Slobbering injector putting too much fuel in the pipes, a low pressure fuel pump not providing enough pressure will cause the high pressure pump to ramp up pressure to compensate, potentially making too much fuel again for the excessive heat. Wiring faults not letting the pcm get accurate information from the sensors. A garage that just replaces defective parts without finding out why they failed, is just as bad as one that does nothing at all.

 

What if it was a defect in the DPF itself?

 

Excessive heat can also be caused by an overloaded dpf when it tries to regen. An overloaded dpf can cause a run-away regen, one that isn't controlled. Too much EGR can cause excessive soot formation in the engine. A cracked CAC can also cause this, but generally comes with low power. A malfunctioning VGT can also cause too much soot.

I just replaced a cracked filter on one of my test trucks because it had developed a hole in a CAC hose. The hole grew bigger over time until the drivers finally noticed it. No fault codes until it was losing a lot of air. By then, the damage had been done.

 

When they agree to replace your dpf, be sure to have them clean the tail pipe as well. This is the ONLY way you will be tell if it happens again.

 

So how much heat are we talking about? What kind of tolerance does the DPF have? Regen increases the temps to burn off the junk. Should't these higher temps shorten the regen time, or are we talking a really large spike in temp? Any signs or symptoms a driver might notice to catch some of these issues before things get too bad?

 

Soot oxidizes in an O2 environment at 600C. A filter will crack if subjected to 650C for too long. That's a 122F temp delta. I doubt you will notice anything unless it gets so hot that the outlet temp sensor derates the engine.

Remember too, high temps aren't the only thing that will crack a dpf. High soot load will also. This comes from an abnormal condition of the engine or incomplete regens.

 

My whole point is that just replacing the dpf, and doing nothing else, doesn't fix the problem.

 

I'm not going to say its not possible, but its highly unlikely.

 

I also made that point in post #9, sentence 2. Great minds think alike.

 

So how do you go about looking for the primary cause? Do you have a check list you follow? Can you test for this, or do you have to start physically start removing pieces for inspection?

 

All of the above. Depending on symptoms, comments made by the customer, verifying the complaint, physical evidence, is what directs your next move. And yes, sometimes gut instinct (and I've got a big gut).

 

I would hope so. From what I've gathered from 08 owners I've run into that are not a member here, they seem to have no clue. I've advised a few with black tail pipes to have their truck checked out, and was told that exhausts pipes are supposed to get black. I've also had several discussions at one of the local fueling stops that used to sell B5, which is OK, except it was LSD B5 and not suitable for the new trucks. Most didn't believe me on that one either.

So out of curiosity, with no known owner complaints except for the color of the tailpipe, where do you look first? And since I've semi-strayed from the OP's comments (sorry), I'll go for the full hijack and ask, how long does it take you to remove the cab now, since I assume you've had some practice?