I'm the one who started the thread entitled "My Truck's in the Shop - AGAIN". The Check Engine light was blamed on a software problem, for which they flashed the ECM. Like most things that run on firmware, there's likely only a single current version of the firmware so I got that fix plus whatever predated it. The service tech specifically said "You're completely updated." No problems with Check Engine light since.

However, as soon as they flashed the ECM I noticed my overhead MPG figure starting to climb. I had been in the mid to high 15's in mixed (mostly city) driving, and since my overhead tends to read ~1.5-2.0 low I presumed I was getting around 16.5-16.75 MPG. Once the ECM was flashed the overhead went from the mid-15's to 16.8 during about a quarter-tank of fuel. That's a HUGE move in so short a time.

I just filled the tank (17.11 MPG hand-calc'd) which gave me a chance to reset the overhead. After blanking out for a moment, the display showed the previous 16.8 figure... then started shooting up. I only had three miles from the gas station to my office, and in that three miles the MPG figure went up three tenths to 17.1. I have never seen "17" on that display before, ever, no matter how I drove.

A few thoughts:

1) I think the ECM flash for MPG definitely has some effect.

2) It's possible that part or all of that effect is simply making the overhead display more accurate. Prior to the firmware upgrade I was showing mid-15's, which given my overhead's historical offset meant I was actually getting around 17 MPG. Sure enough, when I hand-calc'd it this morning I was getting 17.11 MPG. If the overhead has simply sync'd itself to reality and doesn't move much more, then I'd say the firmware update has more to do with the accuracy of the overhead than any change in engine behavior.

3) On the other hand, if the overhead continues to climb and my next full tank hand-calc's to something significantly more than 17.11, the firmware must have had some effect on the engine itself. No complaints here if that's true... I'm already very happy with my MPG figures, and can't wait to see what happens when the weather warms up and they stop selling the winterized diesel.

Someone recently posted the TSB number for the "fuel flash upgrade". Does anyone remember what that number is, and do we know of a website where we can look up TSB's to see details of what they're supposed to fix and do?

 

I would think your truck already has the new flash, the number concerning 04.5's w bad mpg are at the end of my sig, did it help? it didn't hurt at least EDIT : woops, it was at the end of my sig, lost it due to characture constraints. now I cna't remember it. sry.

 

That's why I was asking for more info on the "MPG TSB". I don't know what models it applies to, when it took effect, etc.

SOMETHING changed, and for the better. I'd just like to understand it so I can put the pieces together and share the results here for everyone's benefit.

 

I had the original mileage flash in the fall of 2004 for my 04.5. This flash was supposed to do three things:

1. eliminate white smoke (which I didn't have)
2. increase milage by about 1 mpg
3. increase the accuracy of the overhead computer

Bear in mind, before the flash, my overhead mileage was always within 0.2 of hand calculated. 99% of the time, I use the same pump at the same station, and always fill to just about overflowing.

The flash did two things:

1. DECREASED the accuracy of the overhead (now it reads 1-1.5 HIGH)
2. GREATLY improved the shifting of the 48RE.

What I am trying to say is - DON'T believe your trip computer after the flash. It may read higher (mine did, and does) but my hand-calulated (in other words - REAL) mileage did not change.

 

WACTD, what code did you get for the CEL? I had a CEL at 250 mi. through a P0514 Battery tempeture rationality.......they flashed it with TSB 18-05-06.....there was no mention of a milage fix....but lot of changes are made with no mention of why.....I'm still running on the last fillup....the overhead was off about 2mpg to the good...always a let down when I hand calced it. Maybe the MPG will increase to correct the error....wishfull thikin...lol. It really needs a good pull!

 

Don't worry, I'll still be hand-calc'ing the MPG. My point was that there was a definite change as reflected by the overhead. What I don't know - yet - is whether the change is greater accuracy, or greater mileage.

 

WACTD, The one thing that would help you and all of us with an 06, is give your dealer that done the reflash a call and ask him what reflash they put in your truck. I for one would like to know witch one it is so I can have it put in my truck.

 

How many miles on your truck?

Inquiring minds want to know!

 

I had the TSB 18-007-04. It is a reflash of the ECM on the motor. My truck was misfiring when accelerating. When the dealership done the reflash there are other TSB's also included in the reflash. My truck is now throwing the code p0630. Which is "VIN not programmed in PCM." I talked to the service manager at the dealership and he talked to the technician about the code and the technician said they have had that problem with some trucks where the PCM does not recognize the VIN number. They are going to reflash my truck again to fix the problem. Will let you all know how it goes.....Jon

My truck has 42,500 miles on it.

 

The newer version of the flash to correct white smoke and improve mileage was 18-037-04. There should be a sticker on your rad support that lists the re-flash number on it...

Along the same lines, 18-037-04 improved my mileage by 2-3mpg (hand calcualted) as well as gave it more bottom end grunt. My overhead is slightly high now as well but it was still worthwhile. White smoke....well that is still there but I guess what do you expect for diesel started cold and not always plugged in

 

It's interesting that we all had the same flash, but it affected us in different ways. As I said above, for me, the transmission shifting was much improved, and it was worth it for that alone.

 

Mine is a 6spd so the only way to improve shifting is to keep working out my right arm

 

...~2400 miles so far.

 

Mine's a 6M too, but I'll take the MPG improvement even if it doesn't help the tranny [grin].

 

So what is the tsb reflash # they put on your 06?