The decision to go closed loop is based on engine temperature and time. Even
cold, the ECU tries to go closed loop within 3 minutes. That is why the
sensor is heated. On a warm engine, closed loop should occur in less than a
minute.

If you are not seeing a response, then something is wrong. A bad sensor or
wiring problem will do this. The input leakage at the sensor input is about
.5 volt. This is the same value that the ECU is trying to maintain with a
healthy sensor. Your idea of switching a voltage to the input will have the
same effect as simply disconnecting the sensor. However, either way, you do
not have mixture feedback control. Find what is wrong.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
dooley
Sent: Wednesday, September 06, 2006 9:57 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: O2 Sensor Idea (long)

Heated O2 sensors are cheap and easy to wire up.
I would go this route and not worry about fooling with a toggle switch or
figuring out the correct voltage to send to the ECU.

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?