[Gmecm] P6 ECM information?

Fri Apr 7 13:52:10 UTC 2006

I generally agree... GM has invested thousands upon thousands of 
engineer hours in their code to address all possible operating 
conditions for the engine. How many aftermarket units can enrich the 
mixture after a certain amount of time in PE to avoid engine damage due 
to overheating pistons? How many programmers even know that this is a 
requirement for an engine that will see long periods of time at WOT?

Having played with LT1 stuff, I think the LT1 is one potential piece of 
the puzzle. The optical can be grafted into the base of an HEI 
distributor to adapt the computer to any V8 ever built with an HEI. 
However, precisely because of the optical pickup, it is not as adaptible 
beyond V8's as other GM computers. I don't know the software intimately, 
but the pickup (and thus position interpretation routines) are decidedly 
structured around 8 cylinder operation.

Another possibility might be the OBDI Northstar computer. It isn't 
flash, but is similar to the LT1 computer in capabilities (sequential 
injection, but single ignition output). The code masks for it also are 
more readily adaptible as they accept a normal 1 pulse per ignition 
event triggering signal (in addition to the 6x per ignition stability 
signal). The code masks are set up for DIS operation.

Yet a third possibility would be the Cadillac 4.9 computer. It has 
sequential injection, but distributor ignition and triggering.

The DIY community evolved around the 7730 and related computers because 
they were common as dirt, not because they were the best module to use.

Will

> From: Ryan Hess <rgmecm at yahoo.com>
> Subject: RE: [Gmecm] P6 ECM information?
> 
> It may be better than *writing* assembly, but makes it close to  impossible for us to undo their thoughts.  On the ASICs, does this  mean that we're stuck using whatever crank reluctor and # cylinders  they're originally intended for?  In otherwords, with the 7730,  you can just change the cylinder select and run anything.  If the  timing logic is in the hardware, and built for one specific app,  doesn't that mean that they're no longer universal?
>   
>   Now here's my deal - I very much like the GM code.  They've spent  their money to make it run an engine in all conditions.  I scanned  over the EFI332 stuff, and it's not what I want.  It appears to be  similar to the megasquirt project.  
>   
>   It seems to me like the LT1 computer with the flash prom would be a good base for an aftermarket type computer.  
>   
>   Ryan
> 
> Steve Ravet <Steve.Ravet at arm.com> wrote:  I've never used modula so can't comment, but anything is better than
> writing assembly.  I say that as a person who does some of that for a
> living.  It still comes down to assembler in the end, it's just that if
> it was originally written in a higher level language and compiled it
> will be more difficult to figure out what is actually going on.
> Especially since compilers tend to optimize things away, and reorder
> code to speed things up.
> 
> Another thing to keep in mind is that the 32 bit computers have 2 asics
> in them that handle a lot of the fuel and ignition related I/O.  Neither
> the ignition outputs nor the fuel outputs are driven by the CPU.  Both
> come from the asics, called CIC (configurable ignition controller) and
> TIO (timer I/O).  CIC interfaces to the 18x and 3x position sensors,
> sends the data to TIO.  TIO acts like a distributor for DIS apps, and
> also schedules fuel delivery.  The CPU communicates with these on a
> higher level by programming advance, injector pulsewidth, etc.  The
> asics figure out the details.  TPU is used for things like evap purge,
> IAC, linear EGR, etc.
> 
> I think these boxes are a great starting point for home grown code, but
> there's a lot that needs figuring out, particularly the TIO and CIC.  I
> think it'd be fantastic to get the efi332 code bases compiled and
> running on a GM box.  Maybe it can be done by ignoring the CIC and TIO
> and just using the TPU.  Or maybe you can be the guy who figures out the
> CIC and TIO!
> 
> 730 won't do sequential because it doesn't have enough drivers.
> 
> regards,
> --steve 
> 
>> -----Original Message-----
>> From: gmecm-bounces at diy-efi.org 
>> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Ryan Hess
>> Sent: Thursday, April 06, 2006 5:39 PM
>> To: gmecm at diy-efi.org
>> Subject: RE: [Gmecm] P6 ECM information?
>>
>> I'm working with the 7730 right now, and would like some 
>> extra code  space and processing power.  I'd like to be able 
>> to experiment a  bit...  For instance, I'd like to be able to 
>> toggle between batch  fire and sequential to see the 
>> differences in fuel economy and idle  quality.  Is it worth 
>> it to an average user?  I don't  know...  I think it would be 
>> neat to find out.  The 7730  isn't fast enough to do 
>> sequential... at least I don't think so.   It appears to be 
>> pretty bloated as-is.  I'd also like some more  I/O available 
>> to add some extra features.
>>   
>>   Modula doesn't sound very nice.  Aside from getting the 
>> source code, is there any way around the compiled code?
>>   
>>   Ryan
>>
>> Steve Ravet  wrote:  Ryan, are you 
>> writing your own code that you've run out of memory and CPU 
>> cycles?  The 32 bit computers should have plenty of both, and 
>> there are tuners available for them.  tunercat has a package 
>> for the 96 and 97 pickups, and probably others as well.  I'm 
>> currently working on a USB<-> VPW cable that can be used for 
>> scan tool and reflashing functions on these computers.
>>
>> These computers are programmed in a version of modula, so 
>> there won't be any commented disassemblies.  I do have some 
>> information on the internals of these PCMs, I need to get it 
>> posted one of these days.
>>
>> --steve 
>>
>>> -----Original Message-----
>>> From: gmecm-bounces at diy-efi.org
>>> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Ryan Hess
>>> Sent: Tuesday, April 04, 2006 9:28 PM
>>> To: gmecm at diy-efi.org
>>> Subject: [Gmecm] P6 ECM information?
>>>
>>> Hi everone,
>>>   
>>>   I'm investigating possible upgrades for my P4 computer.  At the  
>>> moment it doesn't have enough processor power or free 
>> space.  I  found 
>>> some information about the P6 family with dual processors 
>> and a  27512 
>>> eprom and/or flash memory.
>>>   
>>>   Now as far as I know, these are the ECMs you'd find on the OBDII 
>>> LT1's  and other cars.  Or maybe I'm all mixed up and what 
>> I'm really  
>>> talking about is a P66?
>>>   
>>>   At any rate, if the dual processor ECM is the LT1 ECM, I 
>> know these  
>>> have been hacked, or at least enough to create the programs 
>> out there  
>>> such as LT1edit (?).  Are there any commented  
>> disassemblies???  Maybe 
>>> more importantly, are there any schematics  of these ECMs?  
>> Or ANY ECM 
>>> a few steps above the P4?
>>>   
>>>   Thanks,
>>>   Ryan