ecu voltage problem

[Kurt Bilinski]

At 08:32 AM 4/30/97 -0700, you wrote:
>I am an FSAE student and we built an EFI computer for the competition.
>There seems to be a problem running it off the car's power supply, ie the
>battery.  When it is hooked up to the battery the computer holds pulse
>widths at around 1 ms per revoltution regardless of throttle position.
>When we hook it up to the standard voltage regulator used for testing in
>the lab the car works perfectly with full rpm and throttle range, but
>can't move because it is attached to an extension cord.  We're using a
>68hc11 processor.  If anyone has had any weird voltage problems like this
>any help would be appreciated.  Thank you,
>Sean
>
>

Get the EE guys over for some serious shielding.  Use a scope to check the
Vcc lines.  You're getting noise feeding in from somewhere.  They need to
do bypassing on all the supply lines.

It's kind of a big deal, maybe get one of the EE prof's over who's good at
EMI, the students probably won't know.

Kurt