TSB 18-037-04:
We now know that this TSB for improved MPG is working for most of us. Would anyone like to speculate on how DC achieved this (I understand Cummins was out of the loop on this)? It’s a pretty impressive change regarding the fuel mileage improvements w/no really loss of power. I’d guess some changes made to the fueling settings played a large roll. Maybe they cut one of the fueling events at times? Just wondering.

 

I have been wondering this same thing. Please see my responses in the other threads; I had mine done this morning.

To me, a non-engineer, the main way to get better economy would be to cut fuel delivery, and cut power. But my truck was as strong as ever on the 35 mile ride home from the dealer - I know, I really romped on it!

 

Scott, I agree with you. Mine runs as strong as ever and the mileage has definitly improved along with no more "pinging". I attributed the improvement to fuel table changes in the software and never gave it too much thought. If anyone knows how they did it I think we would all find it interesting.

 

I had my 2004.5 reflashed about two weeks ago. Results - MPG is improved and the overhead display is more accurate; however, I still seem to have the white smoke issue. Overall, I'm satisfied. Can anyone answer this though - the dealer reflashed with TSB 18-007-04 vice 18-037-04 and claims the 007 is the newest.

 

He's an idiot. The 007 is from February, and was the original flash for 600s, to address engine "flat spot".

Get a dealer who has a clue.

 

Don't know the differences, but there is a lot more in a "flash" than amount of fuel. Timing, control of the multiple injecton events, wastegate control...there are probably between 4000 and 8000 parameters that could be different.

 

I'm nothing near a diesel expert, but from playing with a 7.3 factory turbo IDI, I would guess that a timing change would have to be part of the TSB. I could make that old IDI ping like crazy, and the MPG's would fall off too, if I got a little too ambitous with the timing. Saw simular results after having TSB performed on my truck.

Ted

 

I think what they did was to turn up that gizmo just a little and turned off the other gizmo. That gave us the right reading when the first gizmo got to that setting. One thing is for sure my truck is starting better.

 

I have an appointment for the flash on Nov. 1st. and I hope they grab the right gizmo and don't mess up the others gizmos. I don't know what I would do if I lost my gizmo!

 

The wonderful thing about fuel injection is that you can remap parts of it without touching the other parts. This holds true for varying levels of RPM, boost, throttle load, etc. So my guess is that for certain throttle loads they changed the fueling requirements to something that makes the engine run more efficiently (i.e. better mileage), but they left the others alone. This results in the same full-throttle power, but better mileage around town and on the highway where you're not using full throttle all the time.

As for the trip computer, the way most work is they take the miles per hour, and then divide that by the injector pulse (multiplied by a constant) to get miles per gallon. But that's instantaneous. For the average, I would imagine it takes total miles divided by the total number of gallons used (calculated by summing up the injector pulse multiplied by a constant, with sampling taken every however often). So, they probably just changed that to a more accurate constant to get more accurate mileage.

 

When I looked at the dealers computer, there was only one flash upgrade that was for white smoke, improved fuel consumption, and overhead. So don't worry about getting the wrong one. I think it won't be to many more years before someone will come up with a variable drive ratio overdrive. Once you get to your top speed you would turn a dial and be able to lower your engine RPM to range you want it. (Hoping)

 

Ted - FWIW, that's exactly how it works. They know how much fuel they are trying to inject, and they just add it up and divide it by the number of miles traveled. IMHO if your overhead is *way* off, it might be a sign of something else wrong as the amount of fuel fuel you're burning isn't close to what the 'puter is asking for.