[Gmecm] Back to square one

[Robin Handley]

After a couple of years of researching and playing with GMECM, I thought I
was getting my head around it but, having started thinking about changing
the code in my 16149396 (1227727 with SRAM) from $8D/ANHT to something
possibly better hacked and easier for me to understand all the arrays/tables
required in applying it to a 2 litre 4 cylinder naturally aspirated engine
that will rev to 7000+RPM, I am now confused and need help/advice.

I've read quite a lot recently about Turbo Sunbird code and it being
identical to Sy/Ty code. What I've read tells me that both originally ran on
1227749 hardware, that they are part of the $58 family, and that the EPROM
size fitted to this hardware was 16k, whereas 1227727 & 1227730 hardware
came with 32k EPROMs fitted (what I have). Also, that it is possible to run
$58 code on a 1227730/1227727 if a few ECM pins are wired differently. I
don't have or want IAC or EGR or any transmission connections, so I think
the only one that might matter here is the wire to connect to my injectors.
Have I got the above correct? :-)

So, if I am to do the switch from $8D/ANHT to $58/Sunbird code, and get back
up to where I am now, I need a .BIN (I have something called Sunbird.bin,
but no idea what 4 letter designation this relates to) and I need a
commented hack - for ALDL monitoring, reference, and code modification (I've
done a nifty change to ANHT that I really need to recreate with any new
code). A .ECU would be nice, but I am capable and happy to generate one from
the hack.

I've looked at the .BINs and hacks on www.moates.net (which seems to be a
copy of the www.diy-efi.org equivalent, but with hacks) and found 4 1227749
$58 4.3 Turbo .BINs (1576BBZA58, 1618BBZB58, 4175AYBN58, BBZB1580 - all 16k)
and one $58 hack (AYBN - which is configured for 6cyl but mentions Turbo
Sunbird in the header, and the accompanying .BIN is 32k !!! - This confused
me, can anyone explain?)

Could somebody with a good overview of GMECM put me straight, please. :-) Is
the Turbo Sunbird code the best start point for a 2.0 4cyl NA engine? Is it
the exact same code as the 6cyl 4.3 Turbos, but with different lookup
values? Will Sunbird code run on 16149396/1227727 hardware (I'm in the UK,
so getting new ECM hardware is not trivial) with a dizzy reluctor trigger
feeding an 8 pin GM HEI? (I don't have/want EGR, IAC, or any transmission
related stuff - just something that will run my NA engine's ignition and
injection - after tuning (obviously) - but with clear visibility about what
needs to be set, and what it actually does.) BTW: I have a WBO2 for tuning,
and a MAP sensor with the following ID: 460 7236 (which I believe to be a 1
bar sensor, but this number does not match that on a web site of GM
sensors!)

If so, please advise which .BIN should I start with, and which hack? And can
I reuse my MAP sensor (I believe the $58 code has an option for a 1 bar
sensor)?

Help! (Sorry for all the questions.)

Robin