Bench ecms

mrvette mrvette at bellsouth.net
Fri Aug 7 15:48:47 GMT 1998


What I am trying to say, is  do it the factory wiring way....reguardless of the
wiring position in the car....they did it a certain way for ground loop reasons,
and stray currents (starting etc)   I'd hate to second guess another mans cost
driven design,  especially one that is proven to work.....:-)))        GENE

Bruce Plecan wrote:
> 
> -----Original Message-----
> From: mrvette <mrvette at bellsouth.net>
> To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
> Date: Friday, August 07, 1998 9:12 AM
> Subject: Re: Bench ecms
> 
> >I am assuming you are a EE candidate at a minimun
> 
> Nope, total EE education is radio shack, and reading Forret Mimms.
> As of late reading some other stuff.
> 
> , 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
> 
> >From your post the other day, (I think it was you), I thought you were
> saying just divide them up, and tie them to the intake.  I've been a
> follower of how the manual says to do it.
> Cheers
> Bruce
> >
> >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.
> >
> >--
> >
> >
> >                                ____________
> >Fun under the sun in          //~~~~~~~~~~~~\\
> >Jacksonville, Fl.  :-)))     //______________\\
> >                       /~~~---~   |      |   ~---~~~\
> >                      /|    /______\____/______\    |\
> >                    (( | /      |          |      \ | ))
> >     Mako 'Vettes    | \============================/ |
> > Shift better with   |\ \\[  ]    |mrvette|   [  ]// /|
> >     Automatics      | \/+========================+\/ |
> >                     |~==============================~|
> >                     |_____|                    |_____|
> >-------------------------------------------------------------------
> >

-- 


                                ____________
Fun under the sun in          //~~~~~~~~~~~~\\
Jacksonville, Fl.  :-)))     //______________\\
                       /~~~---~   |      |   ~---~~~\
                      /|    /______\____/______\    |\
                    (( | /      |          |      \ | ))   
     Mako 'Vettes    | \============================/ |   
 Shift better with   |\ \\[  ]    |mrvette|   [  ]// /|
     Automatics      | \/+========================+\/ |
                     |~==============================~|
                     |_____|                    |_____|
-------------------------------------------------------------------



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