better mpgs

[Worktruck]

hi I had a friend write me this tune, said he gets around 22mpgs highway and 16to18 around town in a 02 Yukon. He loaded the same tune to my 2 suburban, basically im looking to improve power and mpgs, I know the basics to hp my friend lnows more, however im not to sure were going in the right direction. ive loaded my stock tun and this one back and forth and don't notice any power or mpg Improvement. Ive read about modding the dfco to stay in longer helps a ton and tried it and it kicks in and out you can see in the log. all help is extremely appreciated, please take it easy on us newbs.



lilboyburbandefco4jimmy4.hpt
suburbanmpg.hpl

[5FDP]

Setting the stoich to 17.5 is pretty pointless, it's not going to make the MPG any better. If you stuck a wideband in the exhaust you'd notice that it's not going to run there anyway.

You need to set the stoich for the fuel you are using as it will also throw off your WOT fueling calculations. Because if you have it set to 17.5 and you command 1.300 in PE that is 13.4 commanded AFR at WOT which is too lean.

Change it back and play with your timing and fine tune the VE and MAF curve if they are off. If the stoich was factory at 14.68, commanding 1.30 in the higher rpm is a little far for making power. Go for somewhere around 12.2-12.5 at WOT to try and gain a little bit but just know there isn't going to be anything world changing as it's all stock and still a heavy ass truck.

Your friend could also have a different gear ratio or different driving habits/commute.

[Worktruck]

I was wondering if that actually helps messing with the stoich settings. ill put that back to stock and change the pe . Also after I do those changes should I turn off the maf and dfco and tune the ve table then turn the maf back on? I heard this is the real way to start tuning. I went ahead and change stoich to stock 14.78 and pe eq to start at 13.49 and goes up to 12.68 from 4800 to redline.

[Worktruck]

lilboyburbanpenomaf7.hpt suburbanmpg2.hpl ok I recently turned off the maf to get the load tuned in the ve table and its getting closer but my dfco doesn't always work and it is saying lean under wot but when I do the math im in the 11.9 to 12.2 range. im going to attach my log and tune im lost on the dfco however when it does work it surges in and out which is annoying..

[luke]

I agree with 5FDP changing your stoich value is going to cause you endless tuning dramas if not a fresh set of melted pistons... I would be having a good read of the TUNING HOW TOOs in this forum and start logging the data so you can make educated changes or you may end up costing yourself a lot more than what your trying to save with MPG..

[Worktruck]

I agree with 5FDP changing your stoich value is going to cause you endless tuning dramas if not a fresh set of melted pistons... I would be having a good read of the TUNING HOW TOOs in this forum and start logging the data so you can make educated changes or you may end up costing yourself a lot more than what your trying to save with MPG..

after my first reply to this post ive since then changed the stoich setting back to stock. So that's taken care of, as far as dfco and pe that's what needs some attention which is what im asking help for..

[dermotw]

DFCO: ok, looking at your values, they are all over the place, to put it bluntly, maybe too many to list;

Speed hyst: should never be 0 (nor should any hyst) set to 1 or 2 mph.
TPS Hyst: same thing, set to e.g. 1%.
Enable RPM - entry, Well I would not set it like that. In the lower gears it needs to be off or it'll be horrible. I disable mine under 3k in the lower 3 gears (of course its not a truck, nor standard either, lol...). Even in the higher gears I set it to e.g. 1600rpm..
Enable RPM - exit, set it a bit above whatever your idle is.
RPM Hyst - NOT 0. Set to e.g. 5rpm or something
MAP Hyst - NOT 0. Set to e.g. 1kpa

Anything I didn't mention, its in the right ballpark...

kr D.

[Worktruck]

thanks for the fast response, I didn't set it to those parameters I will change them now. anything else I can do to improve my tune? As far as I can see my tune is still rich in pe id just like to get it to run with improved power and mpgs is really all im aiming for.