Benching ecms

[Scott Schaaf]

Bruce Plecan wrote:
> 
> With both ecms "running" having the +5v for the sensors tied together
> seems to generate "No Smoke".
> 
> Next question, does this only work with both ecms powered up?.
>   Can I have them wired like this and be running only one at a time?.
> Seems like there is enough internal resistance to the off ecm not
> to hurt things, but I only did this momentarily.
> 
> Would the real answer be using ganged pots?.  I've tried looking in
> my digi-key, and a couple other catalogs, but turned up no sources.
> 
> When doing pulse generators, is it better to use a 558, and use a
> 4017 for getting low rpm signals?.   For those veiwing from afar
> the reason is that I need to get accurate 200 rpm steps.  The gms
> from what I read do interpolation from one step to the next for
> timing etc, so I gots to be close, to read changes accurately.
> 
> Much more and it seems like a commercial used freguency generator
> will be the answer.  So if ya got a working gen please e-mail me.
> 
> Thanks again
> Bruce               nacelp at bright.net

I think you'll find that the 'ON' ECM will try to power the 'OFF' ECM. 
Not usually a good thing, considering that the 5v regs in the 'ON' ECM
is not meant to supply that much current.
				Scott...