The leading edges of the low res circle are 45 degs from each other. We are assuming that the leading edges trigger a counter for the high res signal that is stopped by the trailing edge of the low res signal. I believe this tells the ECM what cylinder is combusting. I know in EE Hack you can turn cylinders on and off, I assume that this shuts the spark and the injector off, does anyone know?
It should shut off the selected injector only. just like the factory scan tool can. The feature wasn't widely available to the aftermarket at the time. I tell people all the time that it is not the scan tool that that has all the self-diagnostic features, it is the ECM that does.
Your sync theory is right on, since the trailing edges happen unevenly, disqualifying them for TDC indication. The leading edges are symetrical, and perfect for TDC indication.
Here is the LT-1 electrical page. http://chevythunder.com/lt1_electrical_page.htm
Hey guys been following your thread, I don't understand everything you guys are talking about. Taking some electrical engineering classes this semester have definitely helped but I don't want to slow you guys down with asking for explanations.
I just dropped by to say that I'm also very interested in a project like this. I would be willing to help however I can with parts, ecms, etc. i have several lt1s I have chip readers I've unbricked ecms so I'm not a total noob just let me know if there's anything I can do
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