[Diy_efi] GM timing signals

[Bill USN-1]

Just a little update incase anyone else decides to play with a GM ECM....
I am using the 7747 TBI V8 ecm and the 2.2 cavalier DIS system on a 1275 4
cyl mini engine with the SPI(TBI) manifold and TB.

I was having trouble working out the timing settings so the 7747 would drive
the DIS properly.
After reading the GMECM paper Steve linked to I started playing with the max
spark, max retard and warm bias. I also decided to call on the 7747 expert
RBob for guidance.

I was manually editing the timing settings in hex editor and also set the
warm bias to 70? and finally got the thing to control the timing properly.
 Then Bob shot me a reply and recommended I go with initial timing vice warm
bias as I was having the spark table showing negative numbers.

All worked good and the table displays correctly.

I have the max retard to -70? max advance to 80?...I set it to AE which is
supposed to be -10? but given the display parameters in tunerpro it still
displays as 80?(90-10=80). 
And the initial advance is set to 70?.

So now the fuel and timing are working correctly and I am getting it dialed
in.
With some help from a mini forum I was able to modify the 5 wire throttle
stepper to be driven by the IAC signal and now properly controls idle speed
as well.

The last thing I am looking to do is add the ESC and knock sensor back in.

Then later I would like to add a VW GT40 supercharger and run the 7749 turbo
ECM. Or possible the later 7427 PCM or maybe just the EBL on a 7747......so
many choices, so little time!!

Thanks for the assist!


Bill
USN-1


-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Bill USN-1
Sent: Monday, March 12, 2007 9:35 PM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] GM timing signals

Outstanding!!!

Time to hook my romulator back up!!
I think I even had everyone of those old papers printed before the big crash
couple years ago.
I will have to go back and see what else I missed!!
Hard to find stuff when you move every 3 years.
Thanks Steve

Bill
USN-1


-----Original Message-----
From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On
Behalf Of Steve Ravet
Sent: Monday, March 12, 2007 8:48 PM
To: diy_efi at diy-efi.org
Subject: RE: [Diy_efi] GM timing signals

Actually, I went ahead and posted this article on the twiki.  Look on
the GMECM page under GmecmPapers.

--steve 

> -----Original Message-----
> From: diy_efi-bounces at diy-efi.org 
> [mailto:diy_efi-bounces at diy-efi.org] On Behalf Of Steve Ravet
> Sent: Monday, March 12, 2007 2:25 PM
> To: diy_efi at diy-efi.org
> Subject: RE: [Diy_efi] GM timing signals
> 
> Bill, take a look at this article written by a previous list member:
> 
> http://diy-efi.org/pipermail/gmecm/2006-February/001434.html
> 
> --steve 

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