When asking ecm questions

[Scot Sealander]

Brent Obermiller wrote:
 
> What about the GN computer on a 2.8L ('87 newer FWD) Chevy.  
(snip)

> 1.) is the DIS remotely compatable, or use the Buick?

The DIS will send the correct stuff to the ECM for ignition.  But
the SFI ECM needs a cam sensor to know where it is in the firing order.
I bought a distributor from an older 2.8 to try and use it as a cam
sensor....  Need a Buick Regal 3800 SFI underhood ECM, anybody got one? 
Wanna trade a 1227749?  Maybe two? ;-)


> 2.) Can the code be modified for the ignition pickup (in degrees) as 
> the 2.8L pickup is in the block (not on the balancer like the GN)

No problem there.

 
> 3.) Would the 2.8L flow enough air through the MAF for idle.

May need to alter the min flow value.  Need to try it.

 
> 4.) Would one use the 2.8L knock sensor with say an '86 knock module, 
> as the knock circuit is integrated in the newer (style) ecm.

Use the older C3 style 2.8L knock module.

 
> Any thoughts?

Forget the C3?  Use something newer, you'll be glad you did.

  
> P.S. Anyone know anything about the Turbo 2.8L Grandprix's ('88 I
> think), like which ECM they use?

Quite a bit, (I own one).  The turbo GP was available in '89 and '90, 
and uses a 3.1L engine.  The car uses a 1227727 ECM, just like (most) 
all the other 'W' bodies.  This is an underhood version of the 1227730.

It is speed density, but the VE tables are VERY poorly calibrated in
stock form, like higher VE's at 60 kPA MAP than at 100 KPA in some
places!  There is also an error in the fuel algorithm in the stock chip.
With the stock cal, the car tends to stall often.

Fix some of the problems, and the car runs very well.  ;-)  I am working
on cals for bigger injectors, a 3-bar MAP, a custom scan tool, etc.

I wrote some "auto-learn" code for the VE tables.  It will fill in a 
new 16x16 VE table with corrected VE values.  The code is not installed
yet (has been re-assembled), and it ought to be interesting if it works.
The routine is so simple, I may post a code snippet, (if it works).


Scot Sealander