'67 w/ '97 LT1 running to factory specs (finally)!!!

[David Curtis]

To reset:   '67 Camaro running factory new Chevy '97 LT1 and 6 speed
tranny.     Evevrything being controlled by a 1995 ECM with stock 1995
Z28 calibration.
  Problem:  Car running rich, fuel trim not adjusting, end result, bad
backfire when shifting under medium to full acceleration.

  Cause discovered:  Although my scan tool was indicating ECM was in
closed loop mode, I was in fact in "limp home mode." Even though the
scan tool shows "closed loop," block learn was disabled (big clue, but I
didn't know it at the time), ECM calling for both fans on, and spark
advance at 22-23 degrees.   This is why my O2 sensors were at 945mV with
no adjustment of the fuel system.
 This I found after all the excellent advice i received here.

   The reason the car was in limp home mode was a Code 43: "spark
control failure".
   I knew that even though I had a '97 motor, I needed to run a '95 KS
to talk to the module in my '95 ECM.   I just FUBAR'd when I got my KS
from Chevy. All I asked for was a knock sensor for a '95 LT1...not
specifically a Z28 KS.  Oops.   The KS I got was for a '95 Vette or
B-Body or D-Body with LT1.    These cars all use a different knock
sensor module in the ECM, among other minute differences.
   Well, I changed my KS last weekend (did you know it sits in a coolant
passage on the bottom of the block???? I do now<gg>).

   Started car, hit monitor mode on my scan tool...and bingo!  Full
closed loop operation, O2 sensors showing proper cross counts, and fuel
trim adjusting.  Went on an extended test drive..no more backfire, and
scan tool showed everything in spec while driving.   (Can someone come
up with a heads-up display for scan tools?<g> Trying to steer, shift and
press buttons on the scan tool got..ummm..interesting.)

  So, again, thanks to all of you who helped here and by private e-mail.
The powertrain portion of my project is finally completed and correct.
           
                Happy Holidays to ALL!!

  Cheers,
 David Curtis
mailto:spdrcr at flash.net