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View Full Version : sierra 2008, AFR doesn't stay constant @ wot



odd boy
January 24th, 2009, 11:34 PM
Hi everybody,

I tuned sierra 5.3L 2008, whenever I got the AFR @ WOT 12.8 by tweaking the PE, it doesn't stay constant after it shifts to the next gear 2, then 3rd. I got this 12.8 in the first one. Any idea??

It goes to 11.7 .... 10.8

odd boy
January 30th, 2009, 05:33 AM
Any help gents!!

mr.prick
January 30th, 2009, 06:06 AM
What are your mods?
It could be a few things, VE table needs adjustment,
injectors going "static", TP% variance ect.

odd boy
January 30th, 2009, 06:29 AM
What are your mods?
It could be a few things, VE table needs adjustment,
injectors going "static", TP% variance ect.

what do u mean by "your mode"?

joecar
January 30th, 2009, 10:07 AM
He means "what are the modifications on this vehicle?".

odd boy
January 30th, 2009, 04:06 PM
ram-air and cat-back

joecar
January 31st, 2009, 11:20 AM
Hi everybody,

I tuned sierra 5.3L 2008, whenever I got the AFR @ WOT 12.8 by tweaking the PE, it doesn't stay constant after it shifts to the next gear 2, then 3rd. I got this 12.8 in the first one. Any idea??

It goes to 11.7 .... 10.8I've seen this before, but I do not know the exact reason... the load is changing but the tables are not accounting for it...

Post log/tune files.

Stealth97
February 1st, 2009, 06:28 AM
I've seen this before, but I do not know the exact reason... the load is changing but the tables are not accounting for it...

Post log/tune files.

Ditto. I have heard of this happening on other ECM's (Non GM, like aftermarket AEM for example), where the AFR is only constant in one gear. I would like more information and I watch this thread everyday.

A new aftermarket PCM called the ProEFI (made by the famous Jason Siebels of AEM fame), might have the capability to tune based on gear, AND I believe he is using a Bosch or Motorola late model style PCM (similar if not the same as GM uses stock).

I need to do more research into this ProEFI thing and see exactly which controller it is and how we can utilize it one day (maybe for circle track racing?)

Eric

odd boy
February 1st, 2009, 11:16 PM
here is the file

GAMEOVER
February 2nd, 2009, 02:25 AM
On my 2008 Silverado, I had the same problem, At WOT my AFR kept going below the command fuel setting's I had adjusted in table [B3618]. With the wideband fitted, and messing around with quite a few adjustments. On my truck(tune), the COT [B0804] was causing the overly rich condition. When I disabled it command fuel was right on,(using WBO2) when I re-enabled it, overly rich!!! So instead of disabling COT[B0804] I adjusted table [B0805] to match command fuel at WOT (richest setting in my tune) it's been working perfectly...:)

odd boy
February 2nd, 2009, 03:36 AM
Many thanks to u boss

joecar
February 2nd, 2009, 07:21 AM
GAMEOVER, I like that solution, make the COTP AFR (is that what that table is?) the same as PE... :cheers:

odd boy
February 2nd, 2009, 07:54 AM
I did it and it is okay now thaaaaaaaaaaaaaaaaaaaaaanksssssssssssssss

ssvolvo
February 3rd, 2009, 01:00 AM
Our 08 2500 HD runs 11 to 1 during COT.



What a PIG!http://forum.efilive.com/showthread.php?t=9467

zacksfoam
March 5th, 2009, 02:50 PM
are there any tunes for this gasser out there? and what kind of tunes are they? economy? perfprmance maybe? thanks in advance!