7747 Spark Map ?

[rr]

Marvin Johnson wrote:

> Hi Y'all,
>
>     I've been lurking for awhile on this list an the DIY list. I'm playing
> with a TBI system on a Jeep six. Using Winbin I've been looking at what I
> believe to be the main spark map. ( Spark advance sub warm bias). If this is
> indeed the main spark map it seems to be very aggressive in this
> calibration. I've compared it to several other bins, and they are all less
> aggressive. I'd like to make some changes but I want to make sure I
> understand what I'm looking at. This map is three dimensional including RPM,
> Advance, and MAP. Would this be more or less equivalent to a stardard
> distributor with vacuum advance? (Very rough comparison) I understand it is
> modified by several other maps.

Yes, it is similar to a standard distrib, with much better control.

>
>
>     I've seen several references to running a crossfire injection with a
> 7747. Would a standard 350 calibration be a good starting place to modify
> from. How does running the IACs in parallel effect the IAC counts and Idle
> speed. Does the power enrichment need to be increased due to the greater
> plenum volume.
>

The best way to pick a start cal is to get the cylinders and tranny correct.
Manual
bin or an auto bin, that one is the most important.

>
>     I've downloaded the DIY and ECM archives and spent considerable time
> looking through them. Searching for 101 isn't very productive, as 101 is in
> the header of a fairly prolific poster.
>

Ah, need to visit some locations:

http://www.diy-efi.org/gmecm/ecm_info/1227747/tunetip.html
http://www.diy-efi.org/gmecm/ecm_info/1227747/prog_101.html
http://www.diy-efi.org/gmecm/ecm_info/1227747/projects/747_ignition/spk747.txt

There's another one for the EcmGuy, but I can't find it at the moment.

>
>     In working on this project I've found I know enough to realize I don't
> know anything.
>
>     I hope this isn't to simplistic for the list.

Not at all, we all started there. . .

BobR.

>
>
> Thanks,
>
> Marvin
>

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