George F.

Background-

I have a 2001 5.3L Vortec and original OEM 4L60E running a hacked computer and standalone wiring harness from Howell EFI in my Jeep. The standalone wiring harness cuts out the BCM, among other things, and shuts off the VATS, etc. This setup is in a Jeep with 1 ton axles and 37" tall tires running a 5.13 gearset, and Howell was supposed to have input the tire size and gear ratio when they hacked the computer.

I would really like to put the trans into tow/haul mode, as the drivetrain/tire setup quite a bit of stress on the trans at highway speeds (which I do occasionally) but it would also be nice to have for four wheeling.

Can I put a permanent command via LS1edit or otherwise into the PCM to force the trans into tow/haul, or do I have to somehow wire in a BCM into the ALDL?

TIA-

wait4me

iTrader: (10)

You cant do it in any other programming software except efilive.
You can set up the different trans mode activation buttons to not need the bcm and can then be a dirrect input to the computer what mode you would like via a negative ground to a specific pin on your pcm.
www.efilive.com has a free download for you to check out the program.

OR maybe someone with efilive can turn on the feature for you.

OBXMarine

iTrader: (2)

Sorry, I can't help, but would like to express interest in your hybrid. Speaking of hybrids, have you posted this question over there?

Back to my point.... I'm planning on doing something simlar with my '78 CJ7 this fall, except I think I lucked out and already have a TH400 behind the stock 258. I hope you stick around and let us in on your experience.

George F.

Recalling that this Howell wiring harness was completely "plug and play" standalone, meaning that if you put 12volts and gas to the motor it would run sitting on a crate. SO, I did not cut any wires except where to splice into the stock Jeep harness, and don't have much of a clue on modifying the pins on the PCM....

is it possible that it would be as simple as using software through the ALDL to designate a wire port on the wiring harness that I ground out to tell the PCM to put the trans in tow/haul? is that what you are saying?

When I put this project together (almost 2 years ago now) someone had advised the following, which at the time made no sense to me:

"Get a BCM from 2001, wire it in series to the Green and Yellow wires in the ALDL, ground a switch, then the BCM tells the PCU to put the trans into tow/haul"

From what I read in your post, it is much easier than that, and I can bypass the BCM altogether?

Dumb newbie question (remember the wiring harness was essentially "plug and play") how do I get a wire into the harness, and to a specific port on the PCU? Are we talking about threading another wire into the loom and through the 300 pin <exaggeration> connector?

George F.

No, I haven't...and didn't find a hybrid forum?

I will probably hang around, I have been wanting to start messing with the tuning more on my setup, and right now its all at the "magic black box" stage in my head.... I have lots of learning to do.

Here are a couple pics of the project:



OEM Camaro exhaust manifolds to make it fit between the framerails:


Wiring in progress:


All "done":

OBXMarine

iTrader: (2)

Awesome project there!

He is the forum I mentioned: Conversions & Hybrids

Back to your concern. I may be fishing here since I'm just getting my feet wet in the tuning area, but couldn't you just edit your standard transmission mode to emulate the tow/haul shift points, extension, line pressure and such?

George F.

Good point on the shift points.... could I accomplish this with ls1edit and a laptop?

OBXMarine

iTrader: (2)

Yes, I have no idea where though.