J-35 Flash (reprogram)

[Jellystone]

I recently went to my local Dodge dealership and had the J-35 flash done on the "big brain" under the hood. To my surprise, my fuel mileage went up some while running lite truck. This past Labor Day weekend we traveled a total of 360 miles (to & from seasonal site) and averaged over 22 mpg. That is a 3500 Heavy Duty long bed dually with 4 passengers and misc. cargo in the truck bed. I haven't had a chance to see what it does pulling the 5er yet . I have been getting around 11.5 mpg pulling just under 14,000 lbs before the flash was performed. I was already pleased with the fuel mileage before while towing & lite truck, but it appears that i've picked up a little extra.---These averages are based on actual mpg figured up by hand and checking the computer generated numbers (mine is actually fairly accurate).

 

[beardedone]

I'd say you have a keeper with that kind of good economy! How has your coolant temperature been, mine is running a little hotter since J-35. It has also developed a slight "engine miss" about every 50 km it seems like the engine shuts off for a nano second and then resumes normal operation. I haven't been quick enough to check my monitor to see if anything reflected there.

 

[Jellystone]

beardedone, mine has not had any engine miss and my coolant temp is still in the same range as before the J-35 so far. I was watching & listening pretty close since it was my first lengthy highway/interstate trip since the reprogram was performed.

 

[cemill]

Jellystone;
What rear end do you have in your truck?

 

[Jellystone]

Rear end is 4.10. Automatic transmission also.

Jellystone;
What rear end do you have in your truck?

 

[Elevatorman]

It sounds as if the J-35 flash is leaning out the mixture somewhat if there are higher engine temps, and better mileage. Any effect on performance? Also they, by leaning the mixture, could be reducing the amount of sooting in the turbo, thus eliminating the "turbo lag" engine fault some, including me, have gotten. I'm going in next week for a re-call and flash up-grade, I'll have to ask. In the meantime Dodge told me to run with the exhaust brake on all the time, that I couldn't hurt it. So far so good! Towing mpg at 10.7 @ 62mph, empty highway around 18 or so, depending where my foot goes.

 

[Willym]

"Leaning out the mixture" effects don't apply to diesels as they do to gas motors. Less fuel means lower exhaust temps and lower power in a diesel. You basically add more fuel to get more power. The soot in turbocharger problem is due to the use of EGR for NOx control. More soot is produced on EGR engines as a result of less efficient combustion. Using the exhaust brake frequently, or all the time, will reduce the frequency of turbo troubles de to soot build up. I had J35 done and didn't notice any real change. It does affect emission control somehow - but who knows how. There are many variables - injection timing, DPF regen points and temperatures, EGR volume, EGR temperature etc etc. The ECM software for the Cummins 6.7 sure is complicated. I run with my EGR disconnected and get less soot, better combustion and fewer DPF regens.

It sounds as if the J-35 flash is leaning out the mixture somewhat if there are higher engine temps, and better mileage. Any effect on performance? Also they, by leaning the mixture, could be reducing the amount of sooting in the turbo, thus eliminating the "turbo lag" engine fault some, including me, have gotten. I'm going in next week for a re-call and flash up-grade, I'll have to ask. In the meantime Dodge told me to run with the exhaust brake on all the time, that I couldn't hurt it. So far so good! Towing mpg at 10.7 @ 62mph, empty highway around 18 or so, depending where my foot goes.

 

[Elevatorman]

After I made my post I looked up the J-35. This was a post from the Diesel Truck Resource web site:

" EMISSIONS RECALL J35
REPROGRAM ECM – REGENERATION STRATEGY
Dear: (Name)
Chrysler has determined that some 2007 through 2009 model year Dodge Ram 2500/3500 trucks
equipped with a 6.7L diesel engine may require reprogramming of the Engine Control Module (ECM).
The problem is... The ECM software program on your truck (VIN: xxxxxxxxxxxxxxxxx) may cause
illumination of the Malfunction Indicator Light (MIL) when no problem exists or
under certain conditions allow heavy sooting of the turbocharger, exhaust gas
recirculation valve and diesel particulate filter. Heavy sooting could damage
emissions components and result in increased emissions.
What your dealer
will do...
Chrysler will repair your vehicle free of charge (parts and labor). To do this,
your dealer will reprogram your vehicle’s ECM. The new software will eliminate
false illumination of the MIL and reduce the potential for exhaust soot
accumulation in your engine and emissions components. The work will take
about ½ hour to complete. However, additional time may be necessary depending
on service schedules.
What you must do... Simply contact your dealer right away to schedule a service appointment.
If you need help... If you have questions or concerns which your dealer is unable to resolve, please
contact Chrysler at 1-800-853-1403."

Thanks for the info on temps. it makes sense now that I think of how a diesel works. This is my first, even my old class C MH had a Dodge gas guzzler. I do not miss that one! I haven't begun to reach break in on this engine yet. But since I've been retired and had to give back the Co. truck the Dodge gets used more and more. Can't stand the mini-van, it's too close to the ground for me!