200q20v Digest, Vol 2, Issue 16

[Huw Powell]

> Sorry, where I I wrote ohms, I meant volts.

>>But have no idea what it does.  Checked out the O2 sensor.  Hooked up, engine
>>hot and running, signal would float between .3 and .7 ohms.  Unplugged it would
>>hang out right around .03 ohms.  With the O2 sensor unplugged, would get a
>>reading of .454 ohms from the computer.  That I can't figure out.

The computer generates its own voltage on that circuit, so when the OXS 
is unplugged, that's what you see.  Why?  I don't know.  Maybe its a 
comparitive factor of some sort, but it has been noticed before.

>>Also, watching the O2 sensor, turning that little pot on the MAF would have no
>>effect on the reading, floated between .3 and .7.

As long as the computer can get the mixture "right," ie, to hover around 
stoich, that is what the OXS will do.  Once you go too far, you'll peg 
it either too rich or too lean.  If the MAF pot actually affects 
mixture, anyway.  I'm not really a 20vt guy...

There are often "tricks" to set these static mixture adjustments so they 
are "appropriate," by observing duty cycles, etc, at the components used 
by the computer to adjust the mixture in response to the OXS.  The 
"right" way to do this, I believe, is with a CO meter, though.

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/