What am I doing wrong. I followed the Auto VE to the T but could really only hit most of the cells 4000 and below. Im dealing with a bad stumble off idle and low speed bucking at around 1600 and below. Im going to post the log files and the tune thats in it now. Can anyone tell me if im even going in the right direction or am I way off in left field trying to punt. This tuning thing had me wanting to kick myself in the head. Any help and info is appreciated.

 

Is that logged A/F correct? It's showing 18.54 at WOT.

 

You must be running a different OS and not the 98. I noticed your MAF table goes to 12khz. The values seem low in the upper tables. Any reason they are flatlined from 11250 and up?

 

This is not on my car. This is on my buddies 02 SS. Its a LS2 403 PRC Heads, Texas Giant on 112 LSA, Full Boltons. Any further info you might have to relate is appreciated. As I stated, Im dealing with a off idle stumble and low rpm off throttle bucking. Any help is appreciated. I tried to follow the auto ve writeup to the t, I have not touched the MAF table at all yet.

 

It's hard to pinpoint without actually driving the car. I did notice what appears to be a stumble at 2110 rpms where the mph drops from 27 to 25 but the TPS stays at 22.7%. The A/F is also at 18.54. You didn't log LTFT's which would help. The bucking you refer to could be a function of the TC locking too early or the shift points set too low and/or the A/F.

 

its a 6spd man

 

Sorry. You should have stated that in your original post.

 

sorry man, my brain is so fried right now. Its a 6spd.

 

248/254, .611"/.613 are the cam specs, LS2 403 with 4cc releifs, LS6 Intake & Stock TB

 

that tune is not opening for me.

 

have you diabled the maf yet? if not go to the engine diag. go to maf fail frequency and set it to zero

 

OK. Several things here. First, you dont have the maf failed. Next you have a good idle dip in it, but its way too rich in the surrounding cells.
Theres too much timing in it in the low load areas, possibly contributing to the surge.
As for your logs, you dont have alot of the pids on that you should. I would turn on the short terms at least, and the 02s. That'll give everyone an idea of what the computer is seeing, and doing.
I redid some of it. Hopefully it works a little better. I failed the maf, and set it up to run in SD. If you dont know how to chart the A/F correction, or STFT vs VE, read up on it, and then start tuning the VE.
If it doesnt wanna run, you may have taken too much fuel out of the VE, if you were doing that with the maf enabled.
You may need to add some more back, and then drive it easy as you plot the fuel trim correction, or A/F correction via wideband.

 

EdCmat, the tune i posted was the tune with the maf reenabled and I corrected the VE from 4000 and below if i remember right. During the SD tuning of the VE we could really only hit the cells from 4000 and below without going WOT and we didnt know if we should go WOT when tuning the VE. Some say yes some say no. I didnt log the right things and ill try to get them logged and reposted. Can anyone post a scrrenshot of info of what exactly they log when tuning the MAF, or exactly which info they use to dial in the maf. Thanks

Brian

 

First you need to make sure the VE is right. It doesnt look right. It had an idle dip, but that was about it.
Yes you can go full throttle tunung the VE. But the object is to stay outta PE because it skews the A/F.
Are you using your chart to plot the A/F correction?

 

What chart to plot the a/f correction are you talking about??? Remember Im using EFILive.

 

Its in the maps. You know what I'm talking about?

 

Which one are you talking about?? one of the preconfigured maps?? Are you talking about MAF Calibration LC1 W02 AFR or Maf Calibration LC1 W02 BEN???