Bench ecms

[mrvette]

I am assuming you are a EE candidate at a minimun, so I shouldn't have to say
anything more than that the engine block is the ground for all sensors,  Not the
body of the car....your starting sequence and the crazy currents through the
battery circuit and etc. could/would drive the computer crazy....and the use of
several grounds/+5volt wires is for the obvious ground/feed loop problems, if
you consider the various possibilities of inductive feedback from other
hi-current wires...you can get my drift.....at any rate, wire it like it says in
the wiring diagrams from your local GM dealer's copy machine....they been very
good to me, when asked nicely.....GENE

Bruce Plecan wrote:
> 
> I had been told the sensor grounds on a gm ecm floated in reference to the
> chassis ground, well that doesn't appear to be correct, everything is just a
> couple tenths of an ohm from true ground.
> With no displayed voltage drops across grounds.
> While still seperated, does it really matter if sensor grounds go to
> chassis, on an actual car?.    If so then where Have I strayed to having
> had sensor ground problems????....
> 
> For coolant temp, and intake air temps, I was just going to share
> resistances.  Tieing grounds together.
> 
> For TPS, and MAP I was going to tie the grounds together, use the
> +5 from one ecm, and then share the sensor's output.
> YES/NO??????..
> 
> Cheers
> Bruce        RPM signals applied to both ecms, and powered up
>                   leds flashed and no problems today.
>                   The cat has grown boarded with the flashing LEDs,
>                   but the staff is acting like their inna stupor.

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