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<DIV>I hooked a scope up to my '93 4.3L Vortec HEI ignition </DIV>
<DIV>and later to my 86 Buick GN DIS ignition to compare and </DIV>
<DIV>contrast. Below is a small bitmap I made to show what I </DIV>
<DIV>found. The EST signal about 6 ms advanced of the ref </DIV>
<DIV>signal, which I think is about 24 degrees since the total </DIV>
<DIV>waveform at idle was 30 msec wide. (Gives me ~667 RPM)</DIV>
<DIV> </DIV>
<DIV>((360 deg / 3 cyl fired) / 30 ms) * 6ms = 24 deg ?</DIV>
<DIV> </DIV>
<DIV>Next time I'll hook Diacom up at the same time and have </DIV>
<DIV>a look at what the PCM thinks the timing and RPM are at </DIV>
<DIV>idle.</DIV>
<DIV> </DIV>
<DIV><IMG align=baseline alt="" border=0 hspace=0
src="cid:003501be6851$4a1e6c20$a678ebd0@mike"></DIV>
<DIV> </DIV>
<DIV>
<DIV>I also scoped the injector output. I could see the spike </DIV>
<DIV>from when the injector closed. (What's it called, flyback?)</DIV>
<DIV>I was able to verify that my PCM is indeed firing the second </DIV>
<DIV>unused injector driver on pin A9. I even hooked an injector </DIV>
<DIV>up to it and listened to it click away as the truck engine ran.</DIV>
<DIV> </DIV>
<DIV>I'm tired, see y'all in the morning. 8-)</DIV>
<DIV> </DIV>
<DIV>-Mike</DIV>
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