Injector Firing Voltage

[Mark Wilcutts]

The injector driver chips used in ECMs are designed to be immune to
flyback. You should see 12V on the line most of the time, then a short
ground pulse of duration equal to the dwell time, then the large spike
from flyback...

-- 
MW

On Sat, 15 May 1999, Bruce Plecan wrote:

> I hooked the scope up to a GM ecm running 8 saturated injectors.  The normal
> 12v only appreared rarely.  The usual voltage of the injectors firing was
> 75-100v..
> So this flyback/kickback, is a very large issue.
> This would seem to imply to me, that the stock ecm doesn't clip the voltage
> by reverse biasing a diode, to contol it, but rather use a scheme, where
> they deal with it.  Maybe clipping these signals has a adverse affect on the
> injectors opening/closing..
>   Jus curious, if this makes sense.
> Grumpy
>