Date:         Wed, 27 Oct 2004 00:39:02 -0700
Reply-To:     TinkerMan <tinkerman007@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         TinkerMan <tinkerman007@YAHOO.COM>
Subject:      Wasserboxer stalling
Content-Type: text/plain; charset=us-ascii

Hello Volks!

This is a well beaten issue.
I've been struggling with this otherwise great running
motor for quite a while.
The symptom is that the engine stalls unexpectedly,
usually when the engine is relatively cold, although
it might happen occasionaly when it's hot.
It usually restarts after 5-10 minutes after fiddling
with the various connections around the motor, but I
never found anything repeatable enough to draw
conclusions for the real source of trouble.

I've suspected the AFM of course, but it seems that if
this was the culprit the engine should have restarted
immediately after switching off but it doesn't (so
maybe I have an AFM problem but it's masked by a more
serious problem).

While analyzing the problem, I noticed that not much
gasoline smell is present at the exhaust, suggesting
some kind of fuel starvation (fuel pump, filter,
pressure regulator etc.).
At other times, no spark was present (I couldn't
always check, because I was alone and couldn't ask
anyone to turn the switch for me).
But weirdly enough, at some times, a spark was indeed
present and still no budge.
Finally, after 5-10 minutes, the engine somewhat
starts.

So I'm still puzzled deciding the source (or sources,
could be multiple problems at once) of this problem.

I've wiggled the Hall sender connector (no, it's not
broken), disconnected, cleaned  and reconnected the HI
voltage ignition cables, the AFM connector, the
ignition coil HV connection, but nothing is repeatable
once the problem goes away.

I have a feeling that this is an ECU related problem,
since the ECU controls both the spark generation as
well as fuel injection, which could explain above
symptoms (i.e. all ignition and fuel systems are ok,
but ECU doesn't issue spark or injection commands,
thus no spark or fuel smell in exhaust).
Now I don't mean the ECU is necessarily deffective -
it could be that one of it's sensors is baffling it
(e.g. AFM, Temp2 sensor, Hall generator, throttle
switch, I have no O2 sensor - it's a 1990 EU Digijet).

I don't want to open up the ECU and connect the cable
for a Digitool, since any mistake might leave me
without an ECU at all, since these are extremely
scarce (1990 2.1L Vanagon/Caravelle) and expensive
here.

So what I need is some kind of flowchart for problem
debug in the field when it occurs, and possible tips
for easy field testing of various potential problem
sources (e.g. Temp2 sensor, AFM, throttle switch,
coil, hall sender etc.) as access for testing these in
the field is not so convenient, especially when no
help is around to turn the ignition switch for you...

Is there some kind of trick to check for ignition
while the turning the switch in the driver's seat
(e.g. a neon or fluoroscent lamp plugged into the coil
HV cable, that can be easily seen from the front...).
And I'm not talking about a special sync strobe.
Something simple and easy to implement.

OK, I'm open for suggestions. Shoot 'em to me,
folks...:-)


=====
Cheers, T-man.

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