I have a 2003 excursion 4x4 with a 7.3, 3.73 rear and have a volant CAI, 4" exhaust from turbo back and Diablo Sports prodigy tuner. I recently purchased a travel trailer and drove it home yesterday and experienced some problems accellerating. I set the tuner to tow mode but didn't adjust the transmission to firm as I normally do as I didn't know if I would turn off the overdrive and if so how that would react with the tranmission being tweeked by the tuner. All was well when I pulled away with the trailer which weights close to 8k lbs empty. I was driving around 40 mph in a city limit and when I applied some gas slightly but not mashing the pedal the motor started to cackle loudly and finally made a lound misfire/backfire. I backed off the fuel pedal and everything was fine. I drive for another 20 miles or so until I got out in the country, relatively flat roads, cruising around 55 mph and again I applied a little more pedal but not mashing it down only to have the same problem with the loud cackle from the engine and a misfire/backfire sound and a loud thump. Hard to describe the sound and misfire/backfire bang. I again backed off and everything was fine. I pulled over and turned off the overdrive feature and started pulling. I didn't have any other problems with the additional torque driving in the drive gear but saw the dummy fuel guage readings that tell you your average mpg drop considerably. My dummy auto mpg guage normally reads 24+ mpg but when actually read during fill up shows an averaqe of 17+. The dummy MPG was reading 10.6 mpg on the ride back so I wonder what type of milage I was getting if the actual is normally 7 mpg less than the reading. I didn't get a chance to fill up yet to check. Any ideas on what could be causing the motor to cackle and loose power/misfire/backfire when accellerating with a heavy load? I don't have any guages installed yet to get any readings. They are on the horizon. Should I never tow with the overdrive on? Should I set the transmission to firm with the tuner along with the tow tune when towing? Could that of caused a stress on the motor or is there possible something going on with the motor. When I got home I reset the tune to the lowest performance setting for fuel economy and modest HP and torque improvements and when I took the truck to work I hit it pretty hard a couple of times this morning and it ran like a top with no problems. Never had any problems towing my 18' jon boat or utility trailer with ATV before. I realize the travel trailer at 8k is a load but hoped the 7.3 would pull it with no problem. This was the reason I bought the excursion with a 7.3 to eventually upgrade our travel trailer and feel really frustrated at this point. I also got an earful from the wife about why the 7.3 diesel was stumbling trying to pull the trailer. Sorry about the long winded saga but I sure would appreciate any help on my situation. This is my first diesel so I am not really familiar with them and trying to learn all I can surfing the net and assocaited forums. Thanks for your input.

 

welcome to the forum, have you tried towing the trailor in other tunes or with the programmer removed?

 

BACKFIRE ?

 

I really don't think the motor actually backfired. It started with loud cackling sound that got progressively louder like a gas motor pings real loud and shortly after acted like it broke down with loss of power and shuddered with a lound noise. I need to figure out how to run the live diagnostics with the diablo tuner to see what it reads when this happens again or find a good diesel mechanic who can troubleshoot it I guess. I found some threads on the net where others had similar problems with the #8 fuel injector not getting enough fuel when towing heavy loads. Seems to be some issues with the 7.3 and the #8 fuel injectors. I am totally ignorant with diesels and have a whole bunch of learning to do in the near future. I have 130k on the motor now and hope to get bunch more out of it before having to replace it or get another vehicle to now tow the heavy travel trailer.

 

the only time I've ever heard a backfire like sound was on a friends dodge when there turned out to be water in the fuel.

Does it get louder as your putting more fuel to it, or does it get loader while stepping on the go pedal steadily?

Is there a chance that your tuner doesnt match the type of injectors you have?

 

Are all your boots tight- No boost leaks ?

 

Thats what I would do,I would pull the programmer and see how she done.

 

The cackle sounds like fuel starvation. When the injectors don't get enough fuel they get real noisy. I would be looking for a fuel supply problem.

 

This was my first time towing the new travel trailer so I will have to experiment some and see how the motor and powertrain respond without a tune. Anyone know of a good diesel mechanic in Maryland or surrounding states that I could have perform a diagnostic check? I read some post on here about a AE scanner. Who makes it? Is there a web site that I can go to for info on what the scanner offers in terms of live diagnostics? I am stabbing in the dark here being green as you know what with diesels.

 

There are several FTE brothers on here from Maryland. I'm sure we can find someone to help you out.
Could the noise be turbo surge? that "barking" the turbo does could be interpreted as a backfire

Barney

 

Here ya go...http://http://www.riffraffdiesel.com...Code=F731-MISC

 

Something was wrong with your link

Riffraff Diesel: Total Ford Enhanced Bundle

 

the "loud thump" maybe turbo surge. does it happen just when the tranny shifts to OD. if so, I suspect surge. only a ported shroud compressor housing seems to be the guaranteed fix for surge. wicked wheels and aftermarket wastegate controllers, etc... will help. but I can pretty much guarantee you only a ported compressor housing (and probably/maybe also a 1.0 A/R turbine exhaust housing) will make the surge go away. that is if you want to keep running tunes. no tunes, no surge.

the cackle is a no brainer. your stuck with a long lead #8. you can install a high pressure oil crossover (HPx) to help reduce oil pressure spikes near the #8, and a fuel rail crossover (FRx) to alleviate the dead head air entrainmnet issue in the fuel rail. I installed an HPx in my 7.3 and it helped alot. I am waiting on an FRx. After both those mods are done, cackle should all but disappear. then of course, the #8 can be replaced with a short lead (whatever the other 7 are), and cackle is completely gone.

you done good gettin' the 7.3. though it does has issues, but they can all be remedied. don't fret. this is what my first hand experience (on my truck) on surge and cackle has shown me. I'm sure there will be plenty of other opinions to follow. also, both surge and cackle are worse when towing and worse with some tunes.

 

I would say it is something in that type of tuner. I tow 12K with my DPtuner and have no problems at all. I have E99 cc 4x4 lb psd. So doing as said above will probably cure your problem. Better oil to both sides and fuel delievery and return is great help. Talk to Clay. He can fix you up.