Help needed reading Ford EEC-IV data stream

[Lloyd Ferguson]

>
>It could be that error codes are all that it stores -- kinda like
>my 85 Grand Prix used to do (it used to not have a serial data pin on the
>ALDL connector)  ...  I've priced the Diacom and think it is a little
>high --- So I'm gonna try to build my own version (at least I'll learn
>something in the process -- that should be worth something)... ...
>It could be that Diacom just doesn't interface to the Ford EEC-IV and they
>are just telling you that it only stores error codes. ...  Do you have a
>shop manual for the car?  And, does it show a "serial data" pin --- if
>so, it should be able to communicate some how to a pc...
>

I have a 1984 Riviera (probably similar to your Grand Prix) and also
thought that it did not have a serial data pin and only stored error codes.
However, I took the car to a mechanic friend of mine who hooked a scan
tool (OTC I think) to the ALDL connector and was able to read the TPS
voltage on the display!

I would love to know how this is done and perhaps build a PC interface, I
got a lead from auto.tech newsgroup about a device called device called
AutoXray,  contacted one Bill Miller (wjm at goodnet.com) who apparerntly
works there and asked him how you get data out of thesee cars, this was his
reply:

  Lloyd:

  In order to monitor data from a General Motors Car,  It is necessary to
  enter into an agreement with GM to get the data and protocol by which the
  card communicates.  Once that is accomplished There is much product
  development work.  The AutoXray XP240 should serve your purposes well
  because of its ease of use and affordability.

I phoned them for an information package on there product but so far no
reply (almost a month).

If anybody knows how this data is extracted please let me know, just for my
peace of mind.

Lloyd Ferguson
CBC Engineering
7925 Cote St. Luc Road
Montreal, Quebec
H4W-1R5
Tel:    (514)485-5340
Fax:    (514)485-5364
E-mail: ferguson at srcing.login.qc.ca