PCM/ECU tuning for economy -- where to find info?
 

When you post a question about tuning to another forum, nobody knows about saving gas. All they know is about making more power. That's the major market for electronic tuning products/services.

I'd like to do some very uncommon adjustments to my 2002 GMC 5.3 V8 and its 4L60E automatic transmission. How can I do this?

I'd like to make it always upshift at a maximum 1500rpm, not downshift even if I go WOT, 3-2-1 positions obey completely, and leave Tow/Haul mode stock (which will give me a single button to press for more normal behavior/fast driving). I'd like to be able to adjust this multiple times through trial-and-error, so it's got to be something I can do myself.

I'd like to make DFCO far more aggressive, coming on immediately anywhere above 1000rpm and staying on until 800rpm.

I asked on the GM truck forum that I frequent, but of course answers will all be about power. I can't really describe my plans there as there's currently a lot of hate for FE discussion (due to people repeatedly asking idiotic questions about it, or just complaining with no question; technical questions get some help but mostly a bunch of bullcrap, kind of like when someone posts here with a big SUV).

In other news, the last 1.1 miles of my commute is coastable except when something forces a stop, such as the construction currently going on. I usually coast in neutral, engine on, then (when in my VW with its manual transmission) EOC the last 80 yards or so where I can see clear to my parking space. Today I did the whole thing EOC and was lucky that there was no obstruction. 1.1 mile EOC FTW! :D

I know this won't work for you but it may be a starting point.

this is a site for chrysler product tuning. you call these guys and they will do whatever as far as the tuning goes. they don't do GM products but they may know someone who does.

I wish I could help you more but maybe this will be a start.

*edit* I forgot to put in the website www.bgchrysler.com

I'm only familiar with older models but does your 2002 still use a vacuum modulator to control shift points or is it all electronic?

Actually, I think I got the reply I need from the GM truck forum after all. Blacbear performance can probably do exactly what I need. I think they might just be using EFILive, but at $200 I'm pretty sure I'm looking at 1/3 of what buying my own EFILive stuff would cost.

Now I just have to decide if $200 is likely to pay for itself. I think I can get 5mpg out of it. Now to the arduous task of figuring out how many miles until payoff...stupid math....someday I'll just make a spreadsheet for it...