[Gmecm] Introduction

[Jared Ryan]

I have been lurking off and on for a while and I wanted to introduce 
myself briefly.

I drive a 1984 Chevrolet El Camino with a 305 V-8 and GM E4ME QuadraJet 
carburetor, and 4-speed automatic overdrive transmission.  The 
carburetor has become very worn and while I still pass the 
state-mandated emissions inspection, I have become very tired of 
adjusting the choke every time the weather changes, and it runs very 
rich at idle, something I've never been able to correct.  I am 
converting it to a TBI system with intake manifold and throttle body 
from an '88-'92 Chevrolet Camaro or Pontiac Firebird.

I'm just at the point that I'd like a little advice and opinions before 
I turn the key with the new (to this car) EFI setup.

The car has CCC so it already has an electronic-timing distributor (no 
vacuum advance), MAP sensor, O2 sensor, and knock sensor.  I can either 
reuse these sensors, where they still apply, or replace them with new 
ones specified for the TBI's donor car, so everything will look very 
stock (a new Painless Wiring harness will help).

This 305 is in good shape.  It has 160K miles and shows strong, even 
compression on all cylinders.  I hope it takes very well to EFI, and I 
expect much better throttle response and at least noticeable economy 
improvements.

Anyway, here is a question.  The ECM I have is a 1278746 with an ANTT 
EPROM.  I did some research online and found that this is from an 
'89-'90 Firebird with 305, TBI and 4-speed automatic transmission.  I 
believe this is an almost ideal match for my vehicle.  The F-body cars 
and El Camino are actually nearly the same weight, even though they 
look nothing alike.  Is this likely a good ECM chip for getting the 
vehicle running and have decent driveability?

I have read hints that the 1278746 is the "car" version of the 1227747, 
which is common in trucks.  I admit I have not yet started scouring the 
archives for more information about this, but I wondered what the 
differences are.  I did notice that there are no disassemblies of the 
'746 on the FTP site, only bins.

Anyway, this is just the project of a hobbyist who doesn't even work in 
the automotive field.  Pictures of the car and of the EFI components I 
have gathered are on my Web site.  I'll appreciate anything anyone can 
offer, and when I am not posting I will be looking at the archives to 
try to learn what I can about these ECMs.  Thanks!

  ---> Jared Ryan <---
jryan at caminofx.org | http://www.caminofx.org
Yahoo!: gerhardr2001 | ICQ: 8457412