Altering ECU Code/Data - GM16 pin OBD-II

[Mike Fahrion]

> I want to know how to alter parameters on this complicated (surface 
> mount EEPROM type) ECU. (SimTec)
> 
> So far I have found out the following :.
> 
> - Looks like Diacom is for monitoring only.
Right, and not OBDII
 
> - Query still in with CarComp Inc.
Also monitoring only (to my knowledge), but is OBD-II
 
> -I know that Superchips know how to re-program via the OBD-II 
> interface (which by the way I think is the ISO9141-2 and not SAEJ1850 
> interface 'cos only pins 3 thro 7, 12 and 16 have physical 
> contacts)...Note the SuperTuner.2001 looks interesting.

If its a late model GM w/16 pin connector, its OBDII J1850 VPW.  This 
at least applies to US models.
 
> - Anybody else know how to do it ?.
Steve Cole at TTS (The Turbo Shop) in California.  They've got a 
product that allows you to reprogram some parameters through the GM 
OBDII interface.
 
> - I guess my real quest is how to get a 1996 GM2litre 16V to run fully open loop 
> for performance reasons only.  The CAT can be put back when returned to 
> road use.  In the UK Group N ECU's were available (189bhp) for 
> pre-CAT early (non-EcoTech) 16V units, but not for later ones.
> 
> Martin

Good Luck
-mike