OK, so here's the problem. In our vans and probably in other'80s cars as
well, the ECU kicks into closed loop mode on the late side, as the O2
sensors are slow to get to operating temp. That's why on later models, car
companies started incorporating O2 sensor heaters.

What this does is give excellent (rich) running when cold, probably what the
engineers were looking for when gas was cheap. But you get worse gas mileage
this way. Probably a lot worse, depending on how much around-town driving
you do.

So here's what I'm thinking. Rather than install a heated 02 sensor to
correct  the problem, why not just supply voltage to the ECU in the correct
amount to trick it into going into closed-loop mode? This could be done with
a transformer, a toggle switch, and a few long pieces of wire.

Start the van in open loop, drive for a few minutes, and instead of waiting
for the ECU to decide it's time, toggle it into closed-loop as soon as it
runs smoothly.

I say this because, having installed one of Ken Lewis' monitoring devices
for the O2 sensors, it's painfully obvious that I'm driving open-loop much
of the time, and thereby wasting gas.

Anybody done this? Heard of it being done? Any reasons it wouldn't work?