JPrevost

Okay, I finally got a chance to hookup my diacom to the suburban. I really like the fast update speed, I want to swap that ecm into my 91. I looked at the injectors and the engine bay and I can't find any obvious difference in the injectors, sensors, and the such except...the PCM trans control and maybe anti-lock brake control. Does anybody think it would be hard to do this ecm swap?
I'm going to try and get a print out on the PCM wires and look at how many I have and how many I would need to add. Would I NEED to have a 4L60e or could I use my 4L60? The injectors and TB unit look exactly the same. The only obvious difference on the intake is the absence of the TV cable for obvious reasons. Any info would be really helpful.

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, Jon (350 TBI!)
91 Red My website

Grumpy

Using an ecm from a 4,500 lb vehicle in a 3500 pound car, is no easy feat. On the C3 series like the 747, it's a much coarser calibration so it's more forgiving. Doing it right would seem to me defeating all the tranny functions, not just disabling the malfunction flags. Unless your into reverse engineering the code that's an awful lot of work.

If you want just about real time updating on a hac'd ecm the look up the info on Lockers and the 747. Uses the edge card connector in the ecm as it's data source.

The fast update stuff does look cool, but it's not that much of a big deal in tuning.

JPrevost

http://www.chuengineering.com/
Is this what you're talking about with the direct interfacing?
I'm still interested in a faster baud speed for data capture and if/when my current tranny goes I'm going to find myself a 4L60e and the 95 tbi ecm. I don't think it would be much of a problem considering tunercat already has a tdf file for it and you could argue that tuning an ecm from a 3500 car and using it in a 3000 car is just as much of an incrimental difference as going from 4500 to 3500. A ratio of .77 compared to .85, doesn't look like that big of a problem. I have to buy that tdf file from tunercat and see what I can do with it in the truck. If it looks good then this might be an alternative to getting an expensive tranny control module. I'd love to adjust shift points, have fast aldl stream updates, and other options that would require extensive source code modification to the 8746 ecm.

Grumpy

<sigh>
well make up your mind, changing trannies changes the whole equation.
Look at the pinout of the PCM you want to use, then get back to me. I'm not going to lead you around point by point thru every detail. Like I said changing from That Truck To That Car is no easy feat.
Application does play a role in what your doing, why do you think GM has so many different ecms and pcms?.
Now after you do some study of the pinouts, get back to me about how much effort this all is going to be, and make up your mind about what tranny you want to use.
Dancing around when asking guestions doesn't get anyone anywhere.