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Re: EFI and Electronic Ignition Initial Start Up Questions [message #367940 is a reply to message #367887] Fri, 10 December 2021 18:38 Go to previous messageGo to previous message
RF_Burns is currently offline  RF_Burns   Canada
Messages: 2277
Registered: June 2008
Location: S. Ontario, Canada
Karma:
Senior Member
Tom,
I'm confused, are you using the standard HEI ignition distributor that came with your 1977 455? or have you switched to an Electronic Spark Control (ESC) distributor??

The ESC distributor has no vacuum advance can on the side and has 4 wires going to the ECM.

The ECM needs to see pulses from the distributor before it operates the injectors. If you are running a HEI (or points) ignition, there is a single wire that connects to the TACH connector. There is also a small circuit board buried in the wiring harness that shifts the level from 12V pulses to 5V. If you are running ESC, there are 4 wires going to the ECM (and the small circuit board, if present, must be removed).


Bruce Hislop
ON Canada
77PB, 455 Dick P. rebuilt, DynamicEFI EBL EFI & ESC.
1 ton front end
http://www.gmcmhphotos.com/photos/showphoto.php?photo=29001
My Staff says I never listen to them, or something like that
 
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