[Diy_efi] Announcement: Honda-oriented ECM/EFI site

[daveb at codyscafe.com]

The DIY-EFI list and its archives are an incredible resource.  I wish I had 
found them earlier.

I am sending this message to spread awareness of a http://pgmfi.crx-
forum.org, a site that is currently devoted to exploring the hardware and 
software used in honda ECUs.  

My eventual goal is through "dirty room" techniques (read: reverse 
engineering) be able to gather enough data on how the core microcontroller 
interfaces with support ICs responsible for ignition timing, fuel injector 
control and sensor monitoring to be able to write a "clean room" open 
source program for most honda engines that is tunable, supports boost and 
external solenoid control (N2O, Vtec) WITHOUT USING ANY HONDA CODE and most 
of all is open source. :)

I've noticed sporadic discussion of honda-related ECUs and management on 
the list archives, and wanted to try to share what we are doing with a 
broader audience.

The current status of the project is mixed, and can be said to be in its 
infancy overall.  

The 84-91 OBD0 ECUs in hondas use 99% intel 8052 compatible micros from Oki 
semiconductor.  Much progress has been made understanding these, but it 
would be unfair to say anything other than full fuel/spark adjustment of 
stock ECUs is possible now.  Several strategies for implementing larger 
fuel/ign tables for boost have been tried unsuccessfully.  Several 
approaches to datalogging are currently being tested.

The 92-95 OBD1 ECUs and a limited number of 88-91 ECUs use the Oki 66X301 
or 66X207 MCU, which use a proprietary core and have no freely available 
disassembler or assembler tools.  I am currently in process of porting GAS, 
the GNU assembler, to the platform, using the M68HC11 port of GAS as a 
reference.  Needless to say, without code tools progress has been slow.  
I'm not a good enough programemr to be able to make rapid progress, and no 
one else has really volunteered to help writing ASM/DASMs.

The 96+ OBD2 ECUs continue to use the Oki 66K series, substituting the oki 
665xx series and becoming increasingly integrated.  There is limited 
discussion of program changes on these computers but most information 
remains unknown.  

Hardware-wise, more progress is being made.  Comparison of ECUs from 
various models with varying features (DPFI vs MPFI, heated O2 sensors vs 
non-heated, Vtec activation vs. single cam profile, knock sensor vs knock-
less, shift light vs shift-light-less, etc.) is starting to provide much 
insight into which parts of the boards are responsible for which secondary 
functions.  It appears that honda/deshinken use a very limited number of 
boards and then leave components off when features are not used.

Additionally, if the forum format appeals to the non-honda related DIY-EFI 
contingent, I would be more than willing to host a www discussion board for 
more general EFI topics.

Hope to see some of the great minds from this site wander by soon!
peace
-Dave


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