Could I please have some confirmation that this
description is correct.
It was my understanding that the green wire was the "O2" signal and
the
other multi wire connection was the sensor heater power.
Nick.
*******************************************
Nicholas Bellgrove
Lecturer - Photography
TAFE SA
Croydon Campus
Goodall Avenue
Croydon Park SA 5008
Australia
Ph +61 8 8204 0993
Fx +61 8 8345 4534
*******************************************
>>> "Yurik Orlowsky" <
href="mailto:yuriko%40iinet.net.au">yuriko@iinet.net.au> 11/23/09 3:25
PM >>>
Les,
The two plugs connect the O2 sensor (3 wire) and the single wire plug
(green
wire) is the heater circuit for the O2 sensor. This wire supplies 12V
with
the ignition on. It would appear that the A/C people used this as a
power
source, with ignition on, for the compressor switch. A short here
would
upset the ECU in the starting mode and also the O2 sensor which
explains
the idle misbehaviour. This is quite an elusive situation.
Glad it is sorted out.
Yurik
From:
Syncro_T3_Australia@yahoogroups.com
[mailto:
Syncro_T3_Australia@yahoogroups.com]
On Behalf Of Les Harris
Sent: Monday, 23 November 2009 11:54 AM
To:
Syncro_T3_Australia@yahoogroups.com
Subject: RE: [Syncro_T3_Australia] VANAGON Electrical problem [1
Attachment]
[Attachment(s) from Les Harris included below]
Nick,
I was about to post a report on this in any event but you have prompted
me
to do it now. I cannot objectively confirm the connection between the
symptoms and the fix, but here's what happened.
Sequence of events:
Friday
* Drove to Bunnings, about 10 k.
* Stopped in car park, idling very fast.
* Switched off engine.
* Came out about 15 minutes later, tried to start engine
* Very high cranking speed but would not fire
* After about 40 minutes, engine fired up, very rough but then
smoothed out
* Drove home 10 k, ran properly but high idle when I reached home.
Saturday
* Found that the idle valve screw had no clearance, readjusted to
.003"
* Cold start was normal, idle was normal.
* Left Seabrook for Carrum Downs, where a group of Syncro owners
was
staying at a caravan park overnight.
* Drove down south east freeway, engine got lumpy when traffic
slowed
for road works
* Stalled at gate of the caravan park and had to be pushed in!
Sunday
* Cold start was normal, idle was a bit lumpy.
* Drove to Cranbourne Racecourse (Day of the Volkswagen)
* Stalled as I was parking, would not restart.
* Tried restarting through the day when the engine was cold but
it
would not fire.
* Tried restarting at the end of the day but the engine would not
fire.
* Got a tow to get me out of the racecourse and the engine
started
under tow.
* Drove to a servo in Cranbourne to get petrol
* Engine would start under tow but would not continue to run.
Note that I had on a previous occasion (several months ago) had the
engine
cut out in the middle of a big roundabout at peak hour. Fortunately, I
got
a restart (a bit lumpy, but it started) and got away.
What Volkspower did was go through all of the signal values until they
found
a glitch in the ignition side. They traced it to a aftermarket wire
that
runs from a plug in the engine compartment to the pressure switch on
the
airco compressor. (I don't know what the function of this aftermarket
wire
is in relation to the airco compressor.)
They found that there was a short in this wire that had thrown the
ignition
system. By the time the Syncro was flat topped to them, there was any
amount of cranking speed but no spark.
Simply removing this wire set everything back to normal. I have only
driven
it a couple of times since, but everything appears to be running
properly.
The plug (see attached pic) is on the left side of the engine against
the
side wall of the engine compartment and is the lower of the two. It
has to
be unplugged when the ignition is being is being reset. I haven't had
time
yet to read up this process in the manual yet but will do so.
I muttered something about !@#$%^&* aftermarket wiring to Dean and he
remarked drily "Yes, but it did take 20 years to fail." He has a
point.
So there it is. A short in a wire fitted as part of the Prestige
airco
installation was the culprit in this case. I cannot yet see the
connection
between the most prominent initial symptom - the high idle - and the
shorting wire but this is not to say that it wasn't the cause. It
could
well have been creating a spurious signal to the ECU until it reached
the
stage where it would not fire at all.
Les
_____
From:
Syncro_T3_Australia@yahoogroups.com
[mailto:
Syncro_T3_Australia@yahoogroups.com]
On Behalf Of Nick
Bellgrove
Sent: 23 November 2009 14:05
To:
Syncro_T3_Australia@yahoogroups.com
Subject: RE: [Syncro_T3_Australia] VANAGON Electrical problem
Les,
Could you please outline the cause of your electrical problem as you
briefly relayed that it was related to the aircon. I have been trying
to
trace a problem with my electrical system for the past 10 years and
have
not been able to resolve it. It may be similar as I have the same
brand
after market aircon. Unfortunately as being located in Adelaide I am
not able to pop around to the same repairer.
Thanks.