Benching Ecms

[T Hergen]

Bruce,

How do you have it wired up?  Something like the following
(used fixed width font to view)?:

  +5 ___
        |
        |
        \
        /<---- to ecm map input
        \
    5k  /
        \
        /
        |
  gnd___|
 
Are the limiting resistors you mention wired in series with
gnd or +5 supplies?  Putting them inline with the connnection
to the ecm probably won't give the desired result.

If there's a pullup or pulldown (or maybe even to some intermediate
voltage) in the ecm, this may cause some voltage other than what you
expected.  Using a 1k or lower pot (instead of 5k) may get the resulting
voltage closer to what you expect. 

No, I haven't tried this myself.

Tom

On Wed, 29 Jul 1998, Bruce Plecan wrote:

> Finally applied power to the bench ecm project today, and all seems
> good and well so far.  Upon reflection I want to run something past the
> folks that have already done this, is using a 5K pot OK for the MAP,
> and TPS??..
>     The reason I ask is that with the MAP twisted to high and with a
> 1K ohm resistor in line, I still get a MAP voltage of 5.1volts.  Should I
> increase the value of the "limiting" resistor?.
>     I also used a 470 ohm resistor thinking that would keep the min
> TPS to about .5volts, but it's .18volts. 
>     What's the error in my thinking here.
> TIA
> Bruce          Ya shoulda seen the staff run when I yelled "Fire in the
>                     Hole", when I flipped the main switch on.     
>