[Gmecm] BLM cell confusion

Tue Nov 15 02:43:21 UTC 2005

Check out some of the DIS stuff on www.thirdgen.org.  I am currently working
on making the Northstar DIS sisytem work on a small block chevy.  It seem
the only thing needed to be changed is  the min and max retard values being
swapped in the bin.  Don't hold me to thins, but I'm pretty sure what needed
changed.  It's something pretty simple, anyway..

JP

-----Original Message-----
From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org]On
Behalf Of WopOnTour
Sent: Monday, November 14, 2005 8:22 PM
To: gmecm at diy-efi.org
Subject: Re: [Gmecm] BLM cell confusion

Gary
I was pondering your comment regarding the differences in the DIS versions
of the GM code, and being unable to find a DIS compatible code.
Have you ever looked at the Quad4 code versions for the '749? ($5C??)
Unlike the 2.0L turbo and $58 these engines used the same ECM but were 6+1
DIS
At the very least maybe there's a way to see what they did differently?
Regards
WopOnTour

----- Original Message -----
From: "Gary Evans" <gary at garyandliz.com>
To: <gmecm at diy-efi.org>
Sent: Monday, November 14, 2005 2:32 PM
Subject: Re: [Gmecm] BLM cell confusion
SNIP

 > As for the 6+1 crank trigger, there have been lengthy threads in the
> past on the differences between the DIS and distributor code. Despite  the
> similarities in wiring and theory of operation, the distributor  and DIS
> codes expect slightly different things to be happening on the  signal
> lines. There is a difference in the timing and dwell  calculations that no
> one ever seemed to figure out (or if they did, I  missed it). Of
> particular interest is this line:
>
> 801B        AA    170 KREFANGL 59.8 DEG SPARK REFERENCE ANGLE
>
> I read about the trials of another GMECM member trying to get DIS to  run
> on distributor code, decided it wasn't worth blowing up my  engine, and
> went with the $a1 code instead.
>
> This google search will lead you to some of the old threads on the
> subject:
>
> http://www.google.com/search?q=gmecm+dis+distributor+base+reference +angle
>
> -Gary
>
>
> On Nov 13, 2005, at 1:16 PM, WopOnTour wrote:
>
>> Gary
>> Nah, you're kidding right? I realize the $88 and $1A calibration  details
>> concern itself with cells 0 and 1 a lot for as these are  idle cells, but
>> I've had a TECH1 scan tool on hundreds of those V6s  and the BLM cell PID
>> varies between cell 3 and cell 15 at road  loads. What scan tool do you
>> use??
>>
>> Also, what difference does the style crank triggering make to the  ECM?
>> That's all resolved by the DIS module itself AFAIK (well  except on the
>> newer OBDII models where the CKP is hardwired  directly to the ECM) On
>> the 122730/727 the ECMs onlly connection to  the ignition system is the
>> EST and BYPASS and the ECM doesnt care  what triggering methods
>> (distributor or DIS) are being employed, as  the CKP is connected to the
>> DIS module not the ECM.
>> Please explain
>> WopOnTour
>>
>> ----- Original Message ----- From: "Gary Evans" <gary at garyandliz.com>
>> To: <gmecm at diy-efi.org>
>> Sent: Sunday, November 13, 2005 1:13 AM
>> Subject: Re: [Gmecm] BLM cell confusion
>>
>>
>>> No really, they exist. The $a1 and $88 masks for the 2.8 / 3.1 V6
>>> engines use only 3 cells. There are probably others, used  primarily  on
>>> "low budget" applications. The customary masks to  work with ($8d  for
>>> example) are performance oriented, so the 16  cell calibrations  are
>>> better known in the GMECM community but 16  cells are by no means
>>> standard across all applications.
>>>
>>> If I was going to start from scratch on my project again, I would
>>> definitely try to use one of the other masks that offer the usual  16
>>> BLM cells. IMHO, the $a1 and $88 code bases are sloppily  written and
>>> not very easy to tune. I am no assembly expert, but  from the work I
>>> have done on the $a1 hac, the code appears to be  a mess. Example: the
>>> injector constant is part of one of the EGR  tables. yeah.....
>>>
>>> However, I need the 6+1 crank trigger DIS, and as far is I know  $88
>>> $8F and $A1 are the only masks that support it out of the box  on the
>>> V6. If there is another mask that supports 6+1 crank  trigger, DIS,
>>> *and* 16 BLM cells, I would love to hear about it  because I am  getting
>>> the itch to do more tuning on my car, and I  might be inclined  to try
>>> something new if it offered better  tunability and cleaner (or  maybe
>>> just better documented) code.
>>>
>>> -Gary
>>>
>>>
>>> On Nov 12, 2005, at 9:05 PM, WopOnTour wrote:
>>>
>>>> Gary
>>>> This post has me a bit stumped
>>>> What about the other 13 cells?
>>>> Don't ALL of the OBDI calibrations use at least a full 16 cell  BLM
>>>> map? (4cells by 4cells) Cells 0 thru 16 ??
>>>> I know some others like the Quad4 ECMs use 16 PLUS and additional  4
>>>> cells (17-20) that depend on "in-gear" state and AC clutch status.
>>>> I've never heard of a GM calibration with only 3 cells...
>>>> WopOnTour
>>>
>>> _______________________________________________
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>>> Gmecm at diy-efi.org
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