Diablosport Forums

can someone check out this log
2010 sierra 5.3 flex fuel
87 oct tune w 87 oct gas 9r18
only mod to the truck is a different muffler with dual outlets

wow! yeah, you're running way rich... it's pulling out a lotta fuel.. trims are at -9 and -10...

they always been like that????? if not, what has changed on the truck since they were last ok???

i guess thats the way its always been...had the tune in it since march and just started logging now. i logged in 5th gear aand a little over 1800rpms. runs good and i average 15mpg.wierd. u would think id get an engine light

nah... GM's threshold is -25 to +25....

I'd go +9% on the slope adjustment....

i swear i can hear a vac leak when i take that vortec cover off. seems like its coming from the pcv line but there are no cracks in it. if so that would put the ltfts in the positives because it would be adding fuel to compensate for the air leak.. right?

rjaro7 wrote:i swear i can hear a vac leak when i take that vortec cover off. seems like its coming from the pcv line but there are no cracks in it. if so that would put the ltfts in the positives because it would be adding fuel to compensate for the air leak.. right?

Correct, yeah you really should have no reason to have the trims off by that much based on the mods you have.

any suggestions

Ok, there is a few things here .... not to beat up on you but!

The PCV system should always have active vacum except during heavy acelleration.

The log you posted has the incorrect parameters selected for a proper FUELING data log....
http://diablosport.com/index.php?name=P ... opic&t=917

also a dirty MAF can put you up there a little, even an improperly installed/aligned sensor. Most MAFs have a keyway type thingy in/on one end to aid in proper direction/installion

recommendations: make sure its clean and installed properly, then relog using the proper PIDs, then adjust the LTFTs as necessary as Lew state .If you need assurance just return here someone will assist.

went back to stock..put on about 100 miles. logged the stock tune using the pids you specified. do the maf reading look ok. its installed with the arrow pointing towards the engine which would be right.

Yes that would be correct ... some/most have a bump/keyway in the/on the end where the hoses connect.
Your log looks good, it was completely warmed up before the log, if so go ahead and adjust your LTFTs +10, you can do it while installing a tune if you want or you can just modify the stock one. Then run it 50-100 miles and do another log.

here is a log on the same road with +10 on inj. slope

Looks much better! ADD +2 more (for a total of +12) and do the 50-100mile again and then relog the same parameters. You are shooting for -2 to 0 on the LTFTs. Once you get that ,you can move on to WOT runs for PE adjustment and K/KR adjustments.

does outside air temp make a big difference in logging. i know one log was done around 40 degrees and another around 60 degrees. also with the 6speed is it best to log between 1800-1900 rpm in 5th gear

yes, temps make a difference....

you want to do data logs in consistent weather conditions...

cooler/cold weather will make the trims more positive compared to warmer/hot weather...

and yes, 5th gear is fine...

by going +10 i believe i made it run richer. i outside ends of my exhaust tips have some carbon on them...never had it before..is it normal or is it too rich