On 8/3/2008 5:47 PM David Beierl wrote:

> 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!  :-)

Oops -- sorry. My bad! Apologies all 'round!

>
>>  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.

Can do. So what am I looking for?

> 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.

M'kay.

> It sounds to me like an ECU issue.  It works ok open-loop at startup,
> or you would have noticed before.

Yes'm - that's true.

> But as things warm up something's
> going to pot.

Not me, alas!

> Mixture is controlled by fuel pressure regulator,

Tested, seems to be hunky-dory.

> injectors,

Not tested. I's afeared of spraying gasoline.

> injector timing/drive from ECU,

Dunno how to test. Could a moderately-skilled Vanagon shop test this?
procedure & specs?

> AFM,

Ditto.

> AFM decoding in  ECU.

Black box mystery, no?

> 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.

I did not see that post -- if it's in the ECU then I'll have two, maybe
three, more on hand tomorrow for test purposes. If it's in the AFM then
please advise so I can inspect.

Many thanks for the assistance. Only 7 days before I drive out of there
hauling a little utility trailer for a 1,000 mile one-way no-return trip
to (Farewell) Bend, Oregon.

--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR