adding electric fan to TBSS, need help with tune

[Boost]

I will post the file soon when I get home. We will be adding LS1 fans on a '07 Trailblazer SS 2wd, bought the harness kit that just plugs in. I need to learn how to modify the tune to support and run this please. Thanks for the help in advance!!!

[ScarabEpic22]

06-07 TBSSs are easy, 08-09s you cant do without patching the .tun outside of EFILive.

Post the tune, look under System -> Fans and you should be able to just change it to suit. Is it a PCM4Less kit? If so Alvin has great instructions on what needs to be done.

[turbo_bu]

ScarabEpic22 or anyone else - have you gone out to the PCM4Less website and downloaded his EFILive tunes for the TBSS's and compared them to your own? There are several listed for 06 - 08 TBSS's. Interestingly enough, there are some also listed with C6 tune segments which I believe is used for the eFans. Those are HPT files only though. Didn't know if anyone had checked into if a CAX file could be made up to do the same in EFILive.

http://www.pcmforless.com/install/fan/

[ScarabEpic22]

If you look, they are also in *.tun format...

The 08-09 ones have everything done outside of EFILive, you cant see any changes except to command a higher PWM value sooner than stock. Not sure exactly what Alvin had to do to enable it, but Im imagining it involved copying code from an 07 OS into the correct area so the ECM can run the fans.

[Boost]

So basically, by downloading the EFILive file provided on that site, it could be flashed into an '07 TBSS and operate as a stock tune with the LS! fans enabled????

[ScarabEpic22]

Yes that should do it, I sourced a set of LS1 fans off a 00 Camaro late last month, my plan is to buy PCM4Less' kit in June/July and then talk with Alvin about what ECM patches need to be done. I assume its just full flashing the right file in, but I want to double check.

[Boost]

So for sure it would have to be full flashed, right? I am doing this VERY soon that's why I need to know. It says on the site to "write entire" the tune, don't just try to copy the changes. Also, since the whole design of the tune is changed (from a Vette?), would it have to be full flashed for that reason? One more thing, what if the file he provided has a lesser number than the one I am running (OS/cal#)? Then would full flashing override it? Or is he supplying the lastest one available for each year TBSS? Thanks!!!

[Boost]

Here is the tune:

10531

[minytrker]

Im just guessing but Alvin probably turned the fans on with HPT and just downloaded the tune with EFI. Thats how I got my E38 standalone to work.

[turbo_bu]

Im just guessing but Alvin probably turned the fans on with HPT and just downloaded the tune with EFI. Thats how I got my E38 standalone to work.

If that were correct, then could we somehow compare those two tunes to see what changes were made and then create a CAX file to do the same in EFILive? From what I have seen for the lean cruise CAX files, it then becomes a matter of knowing which memory address you want to change and what type of changes needed to be made (Hex address, number format, scaling, etc...)

[Boost]

If that were correct, then could we somehow compare those two tunes to see what changes were made and then create a CAX file to do the same in EFILive? From what I have seen for the lean cruise CAX files, it then becomes a matter of knowing which memory address you want to change and what type of changes needed to be made (Hex address, number format, scaling, etc...)

+1
some clarity here would be great. If that's what Alvin did that is really cool on his part and helps him sell the fan parts. But I feel a little handicapped if we have to depend on competing software to get something simple and common like this done :(
(??)

[ScarabEpic22]

See the thing is the 08-09s didnt even have a PWM fan clutch, GM went to a purely mechanical setup for the last 2 years. So those OSs have no provisions for controlling fans at all...06-07s are fine, for a while the only way was to flash an 07 OS into an 08 TBSS.

A .cax would be awesome, but Id definitely want to make sure Alvin is ok with it first.

For those reading along, Im pretty sure the 06 and 07 TBSSs can control LS1 fans without needing any patching done to the ECM.

[Boost]

Yes I saw where the factory tune was controlling the STOCK ones, but have been too busy to read up on whether simply plugging the LS1 fans in (with the harness kit), the tune would still control them the same way?? Because that is what we are doing. And right now I am thinking we have to use the modified tune. Can anyone please clear this up? I looked at the modifed tune provided by them and it has a special table where you can select the TYPE of fan (discrete). So it looks like that's what one would use for non-factory fans. But I would really like to know how it works. Thanks

[minytrker]

If that were correct, then could we somehow compare those two tunes to see what changes were made and then create a CAX file to do the same in EFILive? From what I have seen for the lean cruise CAX files, it then becomes a matter of knowing which memory address you want to change and what type of changes needed to be made (Hex address, number format, scaling, etc...)


You wont see any differences with EFI.

[minytrker]

See the thing is the 08-09s didnt even have a PWM fan clutch, GM went to a purely mechanical setup for the last 2 years. So those OSs have no provisions for controlling fans at all...06-07s are fine, for a while the only way was to flash an 07 OS into an 08 TBSS.

A .cax would be awesome, but Id definitely want to make sure Alvin is ok with it first.

For those reading along, Im pretty sure the 06 and 07 TBSSs can control LS1 fans without needing any patching done to the ECM.

I will look back through the TBSS's I did. I was big into them a few years ago. I dont remember changing OS on the 08's with HPT, I thought it was just a patch but I could be wrong.

[ScarabEpic22]

It just a patch for the 08-09 now, initially people were experimenting with using an 07 OS to get the necessary controls. Its been figured out now using patched files.

[Boost]

Oh cool thanks. So basically, a "patch" is when they go in and add minor stuff as opposed to a custom OS?

[Boost]

Can anyone who has done this chime in? My friend was wondering about the best way to wire it up to the ECM.

[turbo_bu]

Yes I saw where the factory tune was controlling the STOCK ones, but have been too busy to read up on whether simply plugging the LS1 fans in (with the harness kit), the tune would still control them the same way?? Because that is what we are doing. And right now I am thinking we have to use the modified tune. Can anyone please clear this up? I looked at the modifed tune provided by them and it has a special table where you can select the TYPE of fan (discrete). So it looks like that's what one would use for non-factory fans. But I would really like to know how it works. Thanks

From my limited reading, the fan TYPE goes something like this: (note: I reserve the right to be more than slightly off on this one :) )

Discrete = relays. The fans are either on or off. You can do the 3 relay setup like F bodies to get a low speed / high speed thing, but basically the PCM is turning things on and off. NO modulation.

PWM Electric = pulse width modulation driving an electric fan (eFan). The PCM has a PWM driver that is being used to supply power to the fan. Maybe it is just sending power to an electrical driver ??? which then drives the fan?

PWM Electo Viscous = not sure on this one.

PWM Mechanical = engine drive fan (belt driven off of the accessories serpetine belt) with a PWM clutch to control engagement. This might be the option / patch that people are trying to get to work with the eFan options.

Anyone happen to know or want to guess if the patches that HPT's did were to get a PWM Electric option on a TBSS which had a PWM Mechanical to begin with?

[Boost]

http://www.pcmforless.com/install/fan/

[turbo_bu]

Yeah - I saw it mention C6, but was wondering if anyone knew how much / what was put into the TBSS code from the C6. Just a fan segment swap? If so, can that only be done with a Tech II? Assume that this means there is a PWM driver in all the ECM's (06 - 08) which is already in there and just needs to be turned on / mapped to it?

[Boost]

We are doing this today in a couple of hours. Have all the parts, and I verified that the cal# provided by Alvin is the same (and not newer/higher) than what is currently in the truck which is really good. So they did it with a Tech2 you think? Because we have Tech2s here, I had no idea that can be done... :) Let's see how it turns out

[ScarabEpic22]

I guarantee you its not a simply Tech II flash, probably copied code from an 07 to the 08/09 OSs in the correct areas using a hex editor.

[Boost]

That sounds more realistic. Well I hope it goes well, we left it for tomorrow.

[ScarabEpic22]

Full flash the correct MY file, updated with the changes made by their existing tune, and you should be good to go.

[Boost]

Thanks a lot! So FULL FLASH the file provided (what is an MY file?) and I will try to script it or manually make the changes. I will be using the file for an '07 TBSS for EFILive of course from the list in the link a few posts back. Wasn't sure if it had to be full flashed so I am glad you told me. I haven't full flashed anything since I locked up two SSR controllers in a row several years ago. Hopefully we have come a long way since then... :)

[Taz]

MY = model year


Regards,
Taz

[Boost]

oh :) thanks

[Boost]

Here we go...

[ScarabEpic22]

Let me know if you need a hand, should be a full flash of the custom efans tune with the custom normal tune changes copied over. Do the wiring and the install, should be set.

[Boost]

IT WORKS PERFECT!!! PRAISE GOD, thank you guys so much for the help!!!

[ScarabEpic22]

Awesome, Im excited to do my LS1 efan install this summer as well! Gotta save the $$ and buy Alvins kit first though! (And dyno the SS bone stock, then add a tune, then add efans)

[Boost]

Yeah there is definitely lots more room in the engine bay now, and reduced noise. Also he says he can clearly feel the extra power sometimes, which is saying a lot for up to 20 hp. Good deal overall, a very nice and clean install and great function. We are happy with it and thanks again for the advice and support.