Injector Duty cycle calculations

[Marc Piccioni]

My understanding is that the 7730 is a speed density batch fire system, I 
pulled a complete system off a 91 Camaro and had to ring out the entire 
harness to due the violent nature of the sudden deceleration ( it cracked 
the engine block) and all 4 injectors per bank are connected together.

----------
From: 	Scott Knight[SMTP:scott at scottknight.com]
Sent: 	July 23, 2000 11:49 AM
To: 	gmecm at diy-efi.org
Subject: 	Re: Injector Duty cycle calculations

I really hate to contradict the experts here, but my understanding of
SEFI (which is what the system in question seems to be) is that it only
fires injectors once every other crank revolution, just like the spark
plug.  Hence, the available time for injector duration is 18.5 mS at
6500 by my calculations.  I even made a quick little JavaScript
calculator so that I could easily do these things:

http://www.scottknight.com/calculators/js_injector_duration.html

Anyone see any glaring problems with my calculation?  I realize that it
is simple and doesn't compensate for injector opening times and stuff,
but it is merely intended to give an approximate duration available for
the injector to fire at any given rpm (in sequential mode that is).

FWIW, I have heard that Diacom reports half the pulse width for some
reason.  It has done it for the 3+ years I have owned it, and doesn't
look to be getting changed any time soon (if at all).

Later dates.
--
Scott Knight  mailto:scott at scottknight.com
http://www.scottknight.com/ IRC:SS396man
'00 White Grand Prix GTP
'95 Black Impala SS
'94 Ducati 900SS CR
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