7427 Rev limiter / 4L80E question

**RobertISaar** · 02-10-2014

gah.... i wouldn't recommend that.... and if i had to guess, i would expect a 3-position switch. the DTC for it shows a timer for invalid signal, so i don't think a momentary switch would make sense.

what i would do is follow the code far enough back to see where it is getting those mode determinations from.... if it is coming directly from a port on the processor, then you could follow the circuit(s) out to the connectors and you'll know what needs connected and how. if it coming in over SPI/SCI, then things get more fun.

**1BadAction** · 02-10-2014

The reason I say momentary ground, is that's how the LT1 computers did it, and even the 99+ LS1 PCMs have a setting for a depreciated "mom to ground" tow haul mode. Guess you could look at the LT1 programming and see if they have the same modes present?

**dubwise** · 02-10-2014

Thanks again for the responses guys..

1BadAction- Where did you get the $D8 def for the 7060? If you could point me to it that would be awesome.

RobertISaar- Where is the code for the 7060 located? I would like to dig through it for fun to see what I can come up with for the performance / tow mode.

**RobertISaar** · 02-10-2014

i don't appear to have a hack for D8... was one ever released?

**1BadAction** · 02-10-2014

Originally Posted by dubwise

Thanks again for the responses guys..

1BadAction- Where did you get the $D8 def for the 7060? If you could point me to it that would be awesome.

RobertISaar- Where is the code for the 7060 located? I would like to dig through it for fun to see what I can come up with for the performance / tow mode.

Stock $D8 BINs attached. One for the HD Suburban (BAMT) and the other from a 454ss (BAMY). BAMY is a much better starter tune.

**1BadAction** · 02-10-2014

Originally Posted by RobertISaar

i don't appear to have a hack for D8... was one ever released?

No idea, I've been using the AWBK Hack and the BAMY_CAL from the same PCM. Not sure what's different but the items I've added to the XDF all seem to line up and work correctly. IAC deadbands, O2 limits, etc.

Are CAL files the same as Hacs?

(EDIT: attached both)

billygraves · 02-10-2014

........

**1BadAction** · 02-10-2014

Longer gear holds and more spacing between up/downshifts when towing. I'd likely use a table close to stock for the tow/haul, then the normal tables would have my day to day shift pattern, which makes the truck FEEL more responsive.

In the 7060, $D8 Masks, the "Performance mode" Shift tables are all there, and they are complete. The do indeed look like performance tables, not hot mode tables like the later trucks have.

Originally Posted by billygraves

Why do you want to use the Perf Switch? Just asking..... One comment in this. If you see this in the calibration listing or your BIN/XDF, I would look into a few things first. What pins are the PERF Sw meched onto @ the PCM/TCM? If it is a NON-momentary sw, will the switch change, show up in the ADX or data stream? (Does it work?) Are there DIFFERENT 1-2, 2-3, 3-4 Upshift tables,Downshift tables and Kickdown calibrations listed? Will the DTC Function in the Illegal postion and set the diag code?

**RobertISaar** · 02-11-2014

Originally Posted by 1BadAction

No idea, I've been using the AWBK Hack and the BAMY_CAL from the same PCM. Not sure what's different but the items I've added to the XDF all seem to line up and work correctly. IAC deadbands, O2 limits, etc.

Are CAL files the same as Hacs?

(EDIT: attached both)

hmm..... all calibration, no algorithm..... i'm not seeing the alternate shift mode status bytes in the datastream either, so finding the code that deals with it won't be as simple. assuming the perf vs normal tables are done like everything else from the era, at some point, X will point to the beginning of one of them and then offset via a ABX when necessary. that will depend on how the tables are arranged in the calibration too.....

**EagleMark** · 02-11-2014

Originally Posted by 1BadAction

No idea, I've been using the AWBK Hack and the BAMY_CAL from the same PCM. Not sure what's different but the items I've added to the XDF all seem to line up and work correctly. IAC deadbands, O2 limits, etc.

Are CAL files the same as Hacs?

(EDIT: attached both)

I would use the Bamy_cal.src.

All Axxx were superceeded to Bxxx and technically this is $D8, but we left the files as $85 when I did the initial work on $85 files when I had a truck to work on a few days... story here...
http://www.gearhead-efi.com/Fuel-Inj...erceeded-to-D8

**1BadAction** · 02-11-2014

Originally Posted by EagleMark

I would use the Bamy_cal.src.

All Axxx were superceeded to Bxxx and technically this is $D8, but we left the files as $85 when I did the initial work on $85 files when I had a truck to work on a few days... story here...
http://www.gearhead-efi.com/Fuel-Inj...erceeded-to-D8

I just re-read that whole thread, funny how all those posts make so much more sense once you know your way around these bins/masks/etc.

I started with the BAM* based tunes a few months back when I fixed the cam timing issue and had to start all over again. You can't tell by looking at the tune in TP, but the Bxxx tunes are just... Better. Still quirky but not nearly as bad as the Axxx. No wonder all of the A's were superseded.

billygraves · 02-13-2014

.....................

**1BadAction** · 02-20-2014

I can't help but bring this back up... With a 7060 ECM, how, without a way of knowing Low or High range, can a 4L80E shift correctly when the transfer case is in 4WD low?

**delcowizzid** · 02-20-2014

if you are taking speed output off the trans before the transfer yes

**dubwise** · 02-20-2014

Originally Posted by 1BadAction

I can't help but bring this back up... With a 7060 ECM, how, without a way of knowing Low or High range, can a 4L80E shift correctly when the transfer case is in 4WD low?

I like where you are going with this, but did the 7060 come in any trucks that had 4wd? If it did, I would assume one pin would go to ground when you shifted the lever into 4lo....