Bench racing ecms

[Gregory A. Parmer]

> voltage is close to 12V anyway. As long as a power supply can provide
> the current you need, might as well use one, instead of that battery.
> Lot easier, lighter, safer, less smelly; hey, and if you short most of
> the PC supplies out, they drop regulation, fold up their legs, and play
> dead till you cycle the power. Much nicer than a real tractor/auto
> battery, which normally loves to create fires and explosions if you
> short it real good.

I've got my '7747 running on the bench (wall actually) and
if you plug in the real injectors the power supply doesn't
handle things well (scanner freaks out and more). With dummy
loads all is well. I'm using the supply but have a BAT for
more realistic tests.

Problem I'm having is getting the intended feedback. Surprisingly
enough to me, PW seems more closely tied to MAP than TPS.
On a real engine opening the TPS would reduce MAP and thus
increase PW. On the bench MAP doesn't change (just because
of TPS) and blipping the TPS generates only an increased
PW during the blip..similar to an accel pump. Go figger!

Another issue has been the dreaded O2. I'm wondering
if it'll be OK to just fool the ECM into thinking
it's always right...ie, lots of stoich crossings via
a wave gen of some sort. That's next, but I haven't
gotten there just yet. I'm open to better ideas.

> Your idea of an engine simulator, at whatever level, is right smack in
> the stateOdeArt of electronics. Is that SCARY, or what?

Even scarier is dat I'm just crazy enough to be trying
this too!  Albeit not really electronically simulated.

-greg