Kenneth,
You could disconnect the OXS and plug in a potentiometer with an AA battery.
By varying the potentiometer, you vary the voltage between 0 & 1 volt. This
way you could lie to the ECU telling it that the engine is running too lean
(near 0 volts) or too rich (near 1 volt). Automatically, the ECU would vary
the FI cycle to enrich or lean respectively. You could connect the OXS to a
voltmeter and read how rich or lean the engine is really running.
It ain't elegant but its cheap.
-Larry
PS. This would not be kind to your Catalytic Converter

kenneth d lewis wrote:

> David;
> David;
>         I have given this idea some thought. It should be a pretty simple
> circuit, a single,  adjustable gain, opamp to massage the output of the
> O2 sensor. Setting the gain below one should enrich the mixture and
> versa-visa. I would want to install some sort of device to let me know
> when I am starting to destroy the engine. Maybe an exhaust temperature
> gauge.
>
> Drive Safely & Good Luck
> Ken Lewis<Kernersville,NC>86 VW crewcab;60 356B Coupe
> For Sale: 61 AustinHealey Sprite(not Bugeye);Daily driver $2500
>
> On Fri, 14 Jan 2000 20:30:13 -0800 David Marshall
> <vanagon@VOLKSWAGEN.ORG> writes:
> >I have been toying with the idea of making a black box that would
> >allow the
> >driver to control the mixture of the engine.  (If you are with the
> >EPA,
> >please hit delete!)
>
> ________________________________________________________________
> YOU'RE PAYING TOO MUCH FOR THE INTERNET!
> Juno now offers FREE Internet Access!
> Try it today - there's no risk!  For your FREE software, visit:
> http://dl.www.juno.com/get/tagj.