E vs M ALDL pins

[Marteney, Steven J.]

In my 89 F-body, E and M are shorted together. Steve

-----Original Message-----
From: Ludis Langens [mailto:ludis at cruzers.com]
Sent: Thursday, November 02, 2000 3:48 PM
To: gmecm at diy-efi.org
Subject: Re: E vs M ALDL pins


> Mike Martone wrote:
> 
> Also,
> what's up with the ALDL having 2 different (from what i've seen) data
> stream pin locations. One drawing i've seen shows the pin at
> location M while a full blown schematic shows it at pin E. did Chevy
> pull a mid-year boner in that they threw some leftover 870 ECMs into
> these vettes or worse yet....did some early XXX7165 ECMs still
> transmit data at 160 (gack) baud rates before going to 8192?

GM configured the '165's to transmit at either 160 or 8192 baud.  The
ECM wakes up in 160 baud mode.  If it sees a "newer" scan tool, it
switches to 8192.  This was probably so that, in 1986, shops with old
scan tools could work on the new stuff without upgrading scan tools.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/
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