First GenIV LMG swap AFM data logs

[harascho]

well, as we see the AFM stuff is related to the 4wd state this will be our key point for a working AFM in a conversion.

There might be three ways out of it:

1.) The EFIlive crew is able to find a way out with software help

2.) The swap crew is able to find a GMT900 application that has a manual transfer case with no TCCM

3.) Harald (me..) finds a way to use a '07 TCCM from option NP8 to work with a '97 NP241 . I will check the schematics, if we can get 2 hi , 4hi and 4lo to work. We won't use auto 4x 4 for sure.... ;-)

Lets see I will post an update later the day..

Harald

[harascho]

One more thought:

What about running a 2wd tune in the E38 ? Could that be a way to get AFM to work? Maybe worth a try? 2hi, 4hi will work, 4 lo will have trouble finding the correct VSS values which could be solved with a VSS in front of the TC..

[VEGASROBBI]

1.) The EFIlive crew is able to find a way out with software help

2.) The swap crew is able to find a GMT900 application that has a manual transfer case with no TCCM

3.) Harald (me..) finds a way to use a '07 TCCM from option NP8 to work with a '97 NP241 . I will check the schematics, if we can get 2 hi , 4hi and 4lo to work. We won't use auto 4x 4 for sure.... ;-)


Harold,

1) That would be great but might take some time.

2) Did you try the TIS VCI program?

3) Maybe, but NP8 is like Active 4WD and making it work with the old TC?

I changed my calibration to "undefined" 4WD, added the VSS on the Transmission output shaft and both 4 lo and high work fine now. My speedo works in hi and lo cause its on the TC.

I even toyed with the idea of running two VSS's and switching between them when engauging 4 lo; however, I just got back from a 40 mile rock crawl event where I was in 4 lo most of the time and had no codes or problems and averaged 20 MPG to boot.

With this setup it appears my AFM is not inhibited by the invalid 4 lo signal.

This is not the best solution, just one that allows me to have 4 lo, 4 hi, and AFM until a better software solution is available, Robbie.

[harascho]

Robbie, did you check if your AFM is working in 2hi with this setup? What do the AFMINHIB PID's say?

Harald

[VEGASROBBI]

I tried setting my tune too FWD, 4WD, Not Defined and RWD. In all settings the only pid diabling AFM is the "Axle Torque Limiting".

You say this pid is related to 4 lo? Even though I set my tune for 2WD? Maybe it's embedded in the OS?

I haven't downloaded the updated pids yet, will do tonight.

Seems like were making progress finally

[harascho]

You need to use that new file from Ross. With that extracted to the configurations folder the scan tool will show you the correct inhibiting factors. You don't have to make a new data log, just play you old log when you've got the update done. Then you will see that you are ( not you, the E38) in 4lo.... I could bet... ;-)

Harald

[harascho]

Thanks to all over here.
I finally made it. It's not a perfect solution (4wdlo doesn't work) but I have the AFM working in 2hi and 4hi.
After all I tried the '07 avalanche tun file (from 3GNEC12047G152683) which came with my E38.
the calibration and the log is in this post.
I will do some more logs after I changed my dash a little. It seems V4 kicks in only when I almost have no throttle applied. Give it a little throttle and the MAP is out of the V4 mode range.
I will do some better test drives tomorrow here in my area it's up and down all the time.
But man that feels good after all this work... I now have the sound of saving gas as vegasrobbie said.....

So that all shows we have to work on a solution for 4wd applications were the 4wdlo message stuff is solved and 2hi, 4hi and 4lo all work.
In the moment I've got no shifts below 3000rpm in 4wdlo and best of all, the AFM kicks in more than in 2hi......

best regards from Germany from a very proud guy..

Harald

[joecar]

Harald,

You have AFM, 4lo, 4hi, 2hi all working... Good job...

Edit: oh, I see 4lo isn't working properly... well, at least you are closer.

[PSWired]

My theory for the 4LO issue is this:

The ECM depends on a message from the TCCM to determine if the vehicle is in 2WD or 4WD. Since the 4WD state invalid flag is set in the AFM disable PID, I'm guessing the ECM throws out the value from the 4LO ECM hardware input if it sees that 4LO is engaged before getting the message from the TCCM that 4WD is engaged.

Seems we need to find a way to get a message to the ECM (and TCM) that 4WD is engaged. I have pre-wired the harness to my CAN interface module with a 4WD status line, so theoretically if I can determine the message structure for the 4WD engaged message, I should be able to send it to the ECM and TCM from my module.

[harascho]

That sounds good. you could be right that a hardwire 4wdlo input confuses the ECM which is waiting for 4wd message on the CAN before 4wdlo is engaged.
I hope you interface will light up our dark AFM condition corner...

We all are on the right track. I will play with the '07 TCCM schematics, I guess it could be used also for a NP241 to shift 2h, 4hi and 4lo.... give me time until tomorrow..

Last but not least the work is done when all is working, that also includes a correct working 4lo....it's an SUV by its nature...

I will go on a longer testdrive tomorrow to get a feeling for the AFM kicking in and out. I am also curious if the 2wd tune has an influence on my fuel consumption. I read somewhere that the fuelling and tranny behaviour is different in 4wdlo mode to give a better control to the pedal... if that is true my driving was done in 2hi with a E38 thinking it's in 4lo.... I will get some numbers the next days.

So far the V4 mode has some vibrations but the exhaust note is still ok

Harald