ALDL, again

[Padgett 0sirius]

Well just a quick look at my Fiero (1227170/APR0164) ALDL (C3) gives a
stream like this:
000 A4 00 2A 4D C5 00 38 3B 14 80 90 00 20 00 60 24
010 1A 87 90 01 4A 00 97 00 68 A0 00 2A 4B C5 00 37 
020 34 14 80 8F 00 20 00 60 25 1A 88 90 01 4A 00 97 
030 00 70 A0 00 2A 46 C5 00 36 33 14 80 8E 00 20 00 
040 60 24 1A 88 90 01 4A 00 97 00 6E
(then repeats for the next frame).

00 2a (42) is the reported PROM ID. Diacom software interprets as follows:

Engine Speed................... 1275 RPM
Vehicle Speed..................    0 MPH
Coolant Temperature............  224 F
Manifold Air Temperature.......  106 F
Throttle Sensor Voltage........ 0.40 VDC
MAP / Vacuum Sensor Voltage.... 1.08 VDC
Oxygen Sensor Voltage..........  628 mV
Oxygen Sensor Transitions......    1 #
Battery Voltage................ 13.6 VDC
Idle Air Position..............   70 #
Injector Pulse Width...........  1.7 mS
Spark Advance.................. 26.1 DEG
EGR Duty Cycle.................    0 %
Integrator.....................  128 #
Block Learn Multiplier.........  144 #
Closed Loop Status.............  Off
Fuel Mixture Status............ Rich
Battery Status................. Norm
Torque Converter Clutch........  Off
Park/Neutral Switch............  Off
Power Steering Switch..........  Off
EGR Diagnostic Switch..........  Off
Learn Control..................  Off
 
Using available data, it seems likely that the "A0" at offset 019h (sorry,
I find it easier to think in hex) is coolant temp (1.35*160-8), "33" at
offset 039h is the RPM (1275/4=51/33h), & 46h at offset 035h is IAC (70).
Suspect the rest can be decoded the same way once I get a chance to compare
several readings.

Or is all of this common knowlege /way off ? Am trying to come back up to
speed.
      	A. Padgett Peterson, P.E. Cybernetic Psychophysicist
 Anti-Virus, Cryptographics, & Antique Radio Researcher
http://www.freivald.org/~padgett/index.html
 mailto:padgett at gdi.net     PGP 5.5 Key on request