[Gmecm] P6 ECM information? Now: Cadillac ECM info

[Ryan Hess]

If you read some of the responses, like having the caddy computer open  the throttle and try to drag the car through a stoplight...   You'll see why I don't particularly like the motor idea.  To me,  it seems like you could use a couple digital outputs for an IAC control  a lot simpler than building extra circuits.  The IAC/motor problem  seems relatively minor... I'm sure something can be done about  it.  (I also wonder if it keeps an "estimated ISM location", aka  the IAC counts in the code...)
  
  Considering people have definition files for this computer, and  presumably have at least a partial hac, that it would be a nice  computer.  I would assume that it uses dual 6811's, but don't know  for sure.
  
  I particularly like the fact that 50% of the pinouts are compatible  with the 7730.  Repinning a harness is a piece of cake, especially  when half of it is done for you :p
  
  Ryan

Steve Ravet <Steve.Ravet at arm.com> wrote:   

> -----Original Message-----
> From: gmecm-bounces at diy-efi.org 
> [mailto:gmecm-bounces at diy-efi.org] On Behalf Of Ryan Hess
> Sent: Tuesday, April 11, 2006 11:02 PM
> To: gmecm at diy-efi.org
> Subject: Was: [Gmecm] P6 ECM information? Now: Cadillac ECM info
> 
> 
> I just found some info on a relatively common ECM that piqued 
> my  interest.  Apparently, the 16132240, commonly found on 
> 90s 4.9L  cadillac engines is not only sequential, but has 
> tons of RAM and a  512kb chip.  Strangely, it's exterior 
> looks a lot like a  '7730.......  Apparently in caddy style, 
> it uses an idle motor vs  an idle stepper, so don't know what 
> it would take to address  that.  I think it looks promising though.
>   
>   Ryan

I was going to suggest that you go over to thirdgen but I see you've
already posted there.  That PCM apparently uses a linear actuator to
open the throttle plates, rather than an IAC throttling an air bypass
path.  The 2 solutions I can think of are to adapt the cad throttle
motor to your TB, or just use the cad TB.  You might be able to hook the
motor the the throttle itself, or maybe have it move the pintle.  The
other solution is electrical.

According to that thirdgen thread the cad PCM uses a H bridge output to
drive the actuator.  An H bridge is a circuit that can drive an electric
motor at different speeds by varying the voltage, and also in both
directions by changing the polarity.  A PIC could digitize this voltage
and generate IAC steps in response.  I would only pursue this if you
can't make it work mechanically.  Idle control doesn't have to be on the
top of your todo list anyway.  Do you know what CPU it uses?

BTW the thirdgen thread is here:

http://www.thirdgen.org/techboard/diy-prom/331767-caddy-4-9-crank.html

--steve


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