Wow!, I finally found someone else working this swap! I'm knee deep in this also. My 4200 is going into an old Dodge Power Wagon.
The ECU is a huge problem here. It's so integrated to the host vehicle, (Trailblazer). That it may be impossible to re-program for stand alone operation. I has been done, but GM is unwilling to give up any info. I've discussed this with just about every aftermarket programer with the same results: "we can't help you with that engine".
Some other roadblocks are the variable cam phasing & the coil on plug ignition.
However, I have found some who can help:
MoTec:
Can program thier M-600 Computer to run this engine. Real high-end full race stuff. $5000.00+
http://www.motec.com Westers Garage:
May be able to use the ECM from a 3800 Camaro or Firebird to run the IFI and Ignition. But not the cam phasing. They are also triing to hack the stock 4200 ECM to get my engine to run.
http://westers_garage.eidnet.org/scprice.htm Dave Kelton (Dr. K.)
Has access to software & may be able to crack the stock ECM. I sent him my VIN and he's working on it now.
256-543-7165
Squire Inc:
They can clean up your harness and defeat the VATS.
479-243-9115
Speartech:
John Spears has a lot of experience with GM EFI including the 4200. His shop did some programing work on the 4200 for GM and he had them running on a test stand with the stock computer! (see photo's on his website). However, GM took all the stuff back when the project was completed. Maybe if enough of us ask, he'll do some work writing a program so our 4200s can run stand-alone.
http://www.speartech.com/ I hope this helps, I've been at it for about 6 months now, and still don't have a running engine. But I'm that much closer. Let me know how you've made out.
