Newbie

[Shannen Durphey]

Kevin Reynolds wrote:
> 
> I'm working on a project that involves GM's Crossfire Injection. Currently it has the stock 84 vette ECM, but after talking to some people on the list I am going to swap the stock ECM for a 747. I'm sure I'll have many questions, some more stupid than others, but I'll try to keep them to a minimum and in small doses.
> First before I start hunting the boneyards and hacking wires, is there any other ECM I should consider instead of the 747 and why?
747 works well.  It's a  fairly straightforward swap.
> The stock ECM seems to have more wire inputs used than the 747 based on the connector ID chart. Most of the connections are obvious, but obviously some are unneeded(doubtful) or need to be combined. Any and all help on this would be helpful.
Sometimes the names are a little tricky.  One book shows a "sensor
ground", the other shows "tps return".  Having the wiring diagram is
really helpful here.  There may have been an additional battery feed
line on the crossfire ecu.  I didn't have to worry about diverter
valve controls or a/c lines in my swap, as it's in a non emissions,
non AIR application.

> Doesn't GM make a " convert your Crossfire to 747" diagram or harness adapter? :)
You're dreaming here.  <g>

> Since the stock harness to ECM doesn't use a pin connection, are there connectors that will mate to the stock harness? I'd rather make a harness adapter rather than hack off the stock one if possible.

Obtain an ecm from an 82,83 2.5l TBI 4 cylinder and cut up the circuit
board.  Other ECMs may work, I know the 2.5 is the same.
> Exactly what does the calpac do and how does it relate to the vehicle/engine/drivetrain combination? Since >I'm on a budget, when I find the ECM I would like to get it ECM with the right calpac 

Well, calpak's minimal $.  Should be less than $15 through the
dealer.  You'll spend that much buying connectors and terminals for
the 7747 if you get everything through the dealership.  Also, you want
to be prepared to make some small adjustments to the mounting
bracket.  I had an 83 F body bracket, and the ecm sits slightly higher
now.  It may not be a problem for you, I just want to point it out.

and a good starting prom would be nice too. How close does the donor
vehicle have to be to my project vehicle as far as cubic
inches/gearing/transmission etc.
Some 7747 proms cover a wide range of vehicles, some are for specific
vehicles.  You should get a manual trans calibration for a manual
trans vehicle, 350 for 350 (if your car is close to stock).  Consider
anything as a starting point, expect to do some work to the
calibration.
Shannen

> 
> Kevin Reynolds
> 82 Z-28 5.7liter 5-speed with crossfire injection.
>