Newbie needs explanation...

[Bruce Plecan]

-----Original Message-----
From: Barry Tisdale <btisdale at cybersol.com>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, December 20, 1998 9:25 AM
Subject: Newbie needs explanation...


>Hi, everybody, my name's Barry an I'm a........new Syclone owner.  Who
likes to dabble in the engine compartment.  I have a question:

Now, where have I seen this name before <g>. Welcome.
>
>The Sy has port injection, all six injectors electrically in parallel.
Where in the crank cycle are the injectors turned on?

Every third ignition pulse, or once per crankshaft revolution.  The
"on" time is not refferenced to any one particular cylinder.

 I'm interested in when the injectors are 'maxed out', i.e., flowing all the
time.  The injectors have a max 'open time' (BPW = base pulse width?)

As used commonly here, BPW is a base timing.  Meaning what the
ecm starts with before adding any corrections for IAT, CTS, EGR,
etc..

 of 15msec per my scan tool, @ WOT & hi (4800) rpm.  At this rpm, a
revolution of the crank takes 12.5 msec (please correct my math if wrong),
but a 2 revolution power cycle takes 2x that, or 25msec. The ECM gets its
rpm info from the distributor (yes? no?), getting 3 pulses per crank
revolution, uses various parameters to calculate pulse width, and fires the
injectors.  If I want to increase the rpm limit set into the ECM, am I not
going to have to also allow for longer dwell time on the injectors?  Do I
have 25 msec in which to work?

Rather than go item by item lets try this:
  Injectors like to be used only part time, so they have time to cool, they
generally like to run no more than 80-95% of the time.  OTHER
than for a momentary enrichment for accleration.
  At 6,000 rpm you have .010 seconds between crank revolutions so
at 85% duty cycle you'll want the injector on .0085 sec, or 8.5 msecs.
At 3,000 rpm you have .020, secs per rev or a max of 17.msec for
injectors on.
  HTH
Bruce
>
>Is this clear as mud?  My last 'hot rod' was back in the old days of
rejetting carbs & changing distributor curves - this computer control is
*amazing* stuff to me, & I'm just really getting into it now.
>
>Thanks for any feedback - any info greatly appreciated - Barry
>