OK guys so heres another thread for me to be clueless in. i have been casually posing this question for a while but now i'm looking for a straight answer. Everyone always says you need to get a retune for longtubes but i want to know what exactly is being tuned. adding more timing, or is it the VE. all i really know is i still have my stock VE, my MAF has been calibrated, and the truck is running super rich. when it was dyno tuned it was only for WOT so only the MAF was tuned, but now that the LTs are on my fuel trims are ALWAYS above 12 and sometimes maxed out. i have checked for leaks and i cant find a single one. New plugs, wires, swithced the O2s and nothing changes. however, it seems to run nearly exactly the same in SD as when using MAF. Do i just need to tune my VEs. i have been holding off trying to find a leak that didn't exist, and now i'm ready to do it.

 

IMO you need to tune your VE table then your MAF then look into adding some spark.... Do you have a wideband? Which software do you use?

 

still no wideband, i had to buy books for school so the wideband is going to have to wait for now. I'm using HP Tuners.

i drove about 100 miles last night in SD hoping to get my fuel trims learned but it seems like my longterms don't move from -.08 and my short terms float at +-3 but it doesn't run well. it surges a lot at like 60-70% throttle but it intermittently feels strong.

 

wanna post up the tune of what you got?

 

Are you running that Jet MAF in your sig? If so honestly I would take it off and put the stocker back on, put the Jet on ebay... From what I have been told those things just fool the computer into thinking it is colder outside, etc.....

 

i did have problems with the JET in the beginning but my tuner recalibrated it when it was tuned but i could try the stocker if i can find it.

 

Heres my tune that i'm running with SD. can someone look at my VE it looks pretty shitty in my opinion

 

Boohoo HPT won't let me edit your file and send it back to you. I see a few things you're missing. You're not in true SD and this is screwing with your VE table making it WAYYYYYYYYYY too rich on the low end and tricking you into thinking you need more fuel when you don't.

• ZERO out your MAF table to make sure it's not functioning while tuning the VE
• Set your DFCO enable to 284 deg. Your DFCO is making your STFT's appear to be too lean (since the injectors are turning off) and causing you to want to keep raising your VE since your trims will look like +15's and +20's or even higher.
• Set your PE enable to 640 KPA, and your PE rate to zero. This will ensure you're not going into PE while tuning your VE table. Going into PE will F'up your STFT's on the upper end and on engine load. You need this mama dialed in perfectly to get it to run razor sharp.

Posted up is a tune I did recently on an '03 RCSB with a 5.3L (2wd) and 4l60e. Try copying and pasting the VE from this tune into yours (create a new one of course) and then take my advice on the other items. Oh and also don't forget to go under your DTC's and set your MAF high frequency fail to set MIL on first error. Not second like you had it

 

i'll give that a try tonight thanks for the help.

I guess i just wasted 45 minutes smoothing my VE based on my fuel trims from my last 150 miles in what i thought was SD. but oh well, live and learn.

 

Did it myself years ago when I started tuning