[Gmecm] Re: Running V8 with $A1 DIS code

[William Lucke]

Yes... On time over period. The reference signal is 5V for 120 degrees, 
followed by 0V for 60 degrees. That's 66% DC.
If you're talking about *coil* duty cycle, then you need to delineate that.

So the general operational method of DIS is that the DIS module transitions 
the reference signal from high to low when it begins charging the coil and 
transitions from low to high when it would fire the coil, absent timing 
input from the ECM... correct?

Ahh... now I see.
Because all the DIS's use the SAME coil, it needs the SAME charge time in 
all applications. If the coil is charging while the reference is low, then 
that explains the different duty cycles of the different reference 
signals... the coil charge time at a given RPM stays the same regardless of 
number of cylinders.


Will


>From: "WopOnTour" <wopontour at hotmail.com>
>Subject: Re: [Gmecm] Re: Running V8 with $A1 DIS code
>
>Not really
>The formula for duty cycle is ON TIME/TOTAL PERIOD so on that waveform when
>the 60 degree goes low=begin dwell (COIL ON) and will spark (in bypass at
>least) on rising edge of 120 degree portion (after 60 degreees) hence 33%
>HTH
>WOT
>----- Original Message -----
>From: "William Lucke" <william.lucke at highspeedlink.net>
>To: <gmecm at diy-efi.org>
>Sent: Sunday, April 17, 2005 8:58 PM
>Subject: [Gmecm] Re: Running V8 with $A1 DIS code
>
>
> > Thanks for sending that diagram.
> > Looks like the 4 cylinder uses 66% DC, rather than 33%.
> >
> >
> > Will
> >
> >
> >>Date: Sat, 16 Apr 2005 19:22:41 -0600
> >>From: "WopOnTour" <wopontour at hotmail.com>
> >>Subject: Re: [Gmecm] Re: Running V8 with $A1 DIS code
> >>
> >>Really?
> >>Every N* IGN REF I've ever scoped was 50% (toggles every 45 degrees to
> >>create a 4X) The only IGN REF I've ever known not to be 50% is the 4
> >>cylinder engines- which are 60/120 (33%) What pin are you scoping, should
> >>be
> >>PIN C (sometimes labeled "fuel control" in the schematics)
> >>Regards
> >>WOT
> >>
> >>----- Original Message -----
> >>From: "William Lucke" <william.lucke at highspeedlink.net>
> >>To: <gmecm at diy-efi.org>
> >>Sent: Saturday, April 16, 2005 6:46 PM
> >>Subject: [Gmecm] Re: Running V8 with $A1 DIS code
> >>
> >>
> >> > That's a little clearer... thanks.
> >> >
> >> > So the reference signal from a V6 coil pack is 50% duty cycle, right?
> >> >
> >> > I think we've found the problem... the Northstar reference signal is
> >> > 33%
> >> > duty cycle.
> >> > So on a shot pulse, the RPM calculated for that pulse would be 1.5
> >> > times
> >> > actual RPM and the RPM calculated from a long pulse would be 2/3 actual
> >> > RPM. The calculated RPM would bounce back and forth between these
> >> > values 4
> >> > times per revolution... AIUI.
> >> >
> >> > Any way to get V6 DIS code--any mask--to run with this coil pack?
> >> > How does a 33% DC 4X compare to the DRP's from a distributor?
> >> >
> >> >
> >> >
> >> > Will
> >> >
> >> >
> >> >
> >> >>From: "Programmer" <lwester at lincsat.com>
> >> >>Subject: Re: [Gmecm] Re: Running V8 with $A1 DIS code
> >> >>To: <gmecm at diy-efi.org>
> >> >>Message-ID: <002001c541df$c8dbaf00$4250050a at WESTER2>
> >> >>Content-Type: text/plain;       charset="iso-8859-1"
> >> >>
> >> >>
> >> >>No coil pack event every 60 degrees--measurement event, yes.
> >> >>My stupidity apologies to the masses...brain got interrupted by typing
> >> >>again. By comparing the time between pulses on the DIS V6, after seeing
> >> >>the
> >> >>7th slot (sync pulse), every other trigger slot is skipped. The second
> >> >>pulse
> >> >>fires #2/#5, 4th fires #3/#6 and 6th fires #1/#4. There is no coil
> >> >>firing
> >> >>event for the other trigger slots--although they're still
> >> >>monitored/measured. This actually provides a better timing advance
> >> >>signal/measurement.
> >> >>Anyways...this is correct for the '730.
> >> >>
> >> >>Over and out.
> >> >>
> >> >>P.S. Take a look at the LS1 code, someday...you'll see some pretty wild
> >> >>timing values.
> >> >>
> >> >>Back to lurk mode...
> >> >>
> >> >>Lyndon.
> >
> >
> >
> > --
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> >
>
>
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>End of Gmecm Digest, Vol 2, Issue 14
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