Re: Injector opening time

[bcroe@juno.com]

I wonder if someone could clue me in on the part of
fuel injector pulsewidth that is lost to just opening
and closing, no fuel delivered?  What I mean is if
an injector pulsed for 7 ms had an effective open 
time of 5 ms, then a 12 ms pulse (2 ms opening
plus two times 5 ms open) would deliver exactly
twice the fuel of 7 ms

The ECU I am looking at is the old 76 Cadillac analog
unit.  The pick-and-hold seems to put out a constant
1.8 ms "pick" pulse which is fixed in length.  Then the
"hold" part of the cycle is controlled in length by things
like the MAP signal.  Extrapolating the absolute manifold
pressure curve to zero seems to give just about zero
hold time.  This makes me think the "pick" time is not
effective in delivering fuel.  I realize a pulse width vs
fuel delivered measurement would give the answer, but
I am not set up for this now.  So could anyone comment
on the ineffective part of the pulse width for both a 
"pick-and-hold" injector, and a DC injector?  Bruce Roe
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