Re: What model ECM is this ?

[Mark Romans <romans@pacbell.net>]

Hi John:  First of all, if I read the following (attached) email correctly
you have a 90 ecm.

(I received email from a fellow (Hans) in Switzerland the other day, who was
looking for calibration software for his 1990 ZR1. He had the same ECM part
number (1228331). I couldn't find any cal software (Tunercat didn't have
any), but The Turbo Shop (http://www.ttspowersystems.com) has software
available for download on their web site that can scan both the 90-92 ZR1's
and the 93-95 ZR1s (provided you have an RS232 to ALDL adapter ;^) ). Since
you list your ECM as a 1990-1992 model, but your car is a 1995, perhaps
entering the VIN in Diacom makes Diacom configure itself for a 1993-1995
model, which would likely not communicate.

And as for your later email, in which you list the alternate controller
computer that talks to all the ABS, etc. stuff, that one's not required by
Diacom to properly communicate. It's trying to talk to the ECM alone.

Have you checked the actual pinouts on the ECM to see which line is the
"serial data" line, and tried connecting to that? If you do indeed have a
1228331, you *ought* to be able to talk to it!

Food for thought...

Andrew

Compare your bin to a 90 and see what happens.

2nd to learn more about how the ecm works the following gives, in my opinion
the best description of how a gm ecm works.  It doesn't all exactly apply to
the ZR1, but most does.

http://www.thrasher-ep.com/cal_hints.htm

Mark

-----Original Message-----
From: Team ZR1 <teamzr1@teamzr1.com>
To: gmecm@efi332.eng.ohio-state.edu <gmecm@efi332.eng.ohio-state.edu>
Date: Sunday, January 16, 2000 1:21 PM
Subject: Re: What model ECM is this ?


>Mark, I have tried compares with ZR-1 E-proms of 91,92,94 and 95.
>
>I think that since the ECM changed for '91 that I could be limited in what
to
>compare to
>
>I think the older ECM for the Corvette were 8 bit and it was in 94 that a
16
>bit was used for OBDII needs
>Correct ?
>Which processor did they use ?
>
>John
>
>Mark Romans wrote:
>
>> John:  What year prom are you  comparing yours too?  If the ecm is a 90,
>> compare it to that.  I have seen differences like this when the code is
>> offset just a few bytes, when in reality those few bytes are the only
>> difference.
>> Mark
>