Spark lines from o'scope

[John Carroll]

Place another lead any where near one of the sparkplug wires and use it 
for an external sync, or use it as the channel B lead and sync from 
it

john carroll

> From:          A70Duster at aol.com
> Date:          Fri, 10 Oct 1997 00:50:17 -0400 (EDT)
> To:            diy_efi at coulomb.eng.ohio-state.edu
> Subject:       Spark lines from o'scope
> Reply-to:      diy_efi at coulomb.eng.ohio-state.edu

> A bit of help from you all out there.  I attached my inductive pickup from my
> timing light to the coil wire and hooked it up to a port on the o'scope
> (Chan. A).  Got the nice spark lines and coil ocsilations like I should, but
> as RPM changed, so did the grouping of spark pulses.  
> 
> Here is the request:  Is there a simple and cheap ( < $30) circuit that I
> could attach to Chan. B that would adjust for a certain about of pulses
> across the screen, then start over (like when #1 fires).  It should work from
> idle to max RPM (6000).  
> 
> A triangle wave generator would give me the sweep, but at a constant
> rate...???..
> 
> Any help greatly appreciated.
> 
> See ya,
> 
> Mike
> 
> 
John Carroll
jac at wavecom.net