At 04:59 PM 8/3/2008 -0700, Mike Elliott wrote:
>David says that Step #5 doesn't make sense.

Did not did not did not!  :-)

>  There may be clues here for
>someone to suggest what's up.

Unhook the sensor from the AFM and leave it hooked to your dash
meter.  If you want to know when it's hot and working, bias it to 0.5
volts with about a megohm so it will read midscale while it's cold,
otherwise it will read lean.  Or if you want quicker results, swap in
a heated sensor.   Then start it from cold and watch as it warms
up.  Remember it has practically no range -- you only get a
direction, not an amount.

It sounds to me like an ECU issue.  It works ok open-loop at startup,
or you would have noticed before.  But as things warm up something's
going to pot.  Mixture is controlled by fuel pressure regulator,
injectors, injector timing/drive from ECU, AFM, AFM decoding in
ECU.  I'm guessing at intermittent in the AFM sensor wiring/ECU and
in particular at the solder on that big resistor I pointed to earlier.

--
David Beierl - Providence RI USA -- http://pws.prserv.net/synergy/Vanagon/
'84 Westy "Dutiful Passage," '85 GL "Poor Relation"