12200411 PCM swap for 1996 to 2000 GMT400 trucks

[3rd Coast Z]

Are you sure the tow/haul is activated in the computer? Granted mine is hooked up to a momentary switch, but the button can't be depressed more than 1/2 a second. It's really quick.


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[Lextech]

Are you sure the tow/haul is activated in the computer? The button can't be depressed more than 1/2 a second. It's really quick.

X2. Tow/Haul has to be enabled in the tune. Just press the button like you would an elevator---Just a quick press.

Jeff

 

[TerryD]

The thing about grounding a bare wire vs using a switch is you have the chance to get several signals sent where most switches are designed to not "bounce" or "chatter" giving only one good signal.

In industry most switch contacts are spring loaded with them making and/or breaking before the actuator makes full travel which helps prevent issues like this. Think about how a light switch makes a fast snapping close or open and your living room lights don't flicker on and off.

 

[98-Z71]

Thanks for the input guys. I just got a tuned PCM from Black Bear and changed my mind midway through the process and decided I wanted the sport mode so I wasn't 100% sure if the tow/haul had wound up being activated. But, grounding it a little longer (half to full second) did the trick.

 

[TerryH]

Sorry if this is a stupid question....

I was trying to decide if the 411 swap and adding tow/haul to my 96 C3500 dually 7.4/4l80e would be worthwhile if I plan to leave it pretty much stock? It's my daily but I also pull my race trailer which weighs 8200ish lbs. several times a year including some pretty long trips. Appreciate any advice.

Thanks,

Terry

 

[rmoreaux1]

I just ordered my pcm from Lextech. I just added a magnaflow muffler and it seems like I picked up decent power out of the change. The truck just runs noticeably better. The pcm swap is gonna be needed when I change to the zz502 cam and upgraded fuel injectors. I can't wait to get started on the swap.

 

[TerryH]

Had a package from Lextech in my mailbox today. Can't wait to get it installed!!!! Thanks so much Jeff!

 

[Whipped96]

Had a package from Lextech in my mailbox today. Can't wait to get it installed!!!! Thanks so much Jeff!

One of the best swaps that you can do!

 

[rmoreaux1]

That's great. Mine should be here soon. I'm accumulating parts for the cam swap and I'm disappointed that I didn't dyno mine stock. I am going to dyno it with the stock pcm and then after the 411 swap. My buddy has a brand new dyno and we are wanting actual hp and tq numbers for each step of the way.

 

[96C1500]

That's great. Mine should be here soon. I'm accumulating parts for the cam swap and I'm disappointed that I didn't dyno mine stock. I am going to dyno it with the stock pcm and then after the 411 swap. My buddy has a brand new dyno and we are wanting actual hp and tq numbers for each step of the way.

Make sure you post results, should be interesting

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