No COS fuel trim, what did I fat finger

[joeygc5]

Truck is an 8.1, stall, rear mount PT88mm. Truck has been running the last 1.5 yrs on a SDCL 1 Barr tune and now I'm converting to COS3. Truck will start and idle, however I have no fuel correction. I thought I have all tables correct, but obviously I'm missing something. Log and tune attached, truck currently idling at 13.5-13.9a/f so I still need to do further VE tuning.

[joecar]

Hi Joey,

Can you post the COS3 .tun file and the non-Cos .tun file that you started from.

Did you full flash in the COS3 file and then cal-only flash from the non-COS file...?

[joeygc5]

heres the old 1 barr tune

Ifollowed the instructions to the letter of the COS guide. As for loading, cos then cal only, then reading, and modifying file from there. In the orig tune i did change b3601 and b3647 several times trying to see if it made any difference. Also on the original tune it was setup for .9Barr of boost in SDCL 1.25bARR map.

The tune is setup very closely to my Turbo K2500 which runs a 2005 COS3 also and I just can't think of what I did wrong, as my k2500 runs perfect. Also for some reason its placing the attached files in the meassage body???

[joeygc5]

Well I've spent the last several hours making changes with no positive results. I even returned Closed Loop fueling completely on with no response. I'm going to see if I can get a newer 2003 8.1/Allison operating system (currently cos 01350003 for orig os 12579405) to see if anything happens.

[joeygc5]

Well 2 stock OS's (12579405 and 12593059) work fine in CL and Semi-CL modes, the two COS's for the stock OS's (03150003 and 03190003) will not perform semi-CL with b3601, b3605, and b3648 all matched and adjusted from 14.62 to 14.92. I've verified all values were within range and I've given up on this truck. The stock OS is back in and running 1Barr SDCL with a max boost of 10psi.

Oh well

[joecar]

I haven't checked in the COS tutorial, but are those COS's the ones that correspond to those stock OS's (according to the table in the tutorial)...?

[joeygc5]

Yes the orig OS and corresponding COS ae in posted in order, the COS are the 2-step/valet versions. Wierd because my 01 Vette, 05 K2500, and 01 C1500 are all running COS's with the exact same settings and no issues. I think its just the truck lol I pulled the tune attachments also btw