Date: Sat, 10 Mar 2001 13:36:49 -0600
Reply-To: Mark Ingalls <ingalls_mark@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Mark Ingalls <ingalls_mark@HOTMAIL.COM>
Subject: Re: wanagon
Content-Type: text/plain; format=flowed
Hi Stefan,
Greetings from the USA.
The 02 sensor needs to get hot from the exhaust gas before it sends a
voltage signal. So until the 02 sensor is hot, or if the 02 sensor is
disconnected, the engine computer runs only on data from the other sensors.
It has no feedback from what's actually coming out the exhaust. This is
'Open Loop'.
When the 02 sensor is in service, hot, and sending data to the computer,
that is what they call 'closed loop'.
I learned all I know form the Vanagon list, and also from a book "Bosch Fuel
Injection and Engine Management" by Charles O. Probst. It is published by
Robert Bentley. It covers the FI system on the Vanagon in excellent detail.
It sounds like your engine is getting lazy when it is going into closed
loop, when the 02 sensor gets hot and sends a signal. Mine used to do that.
I read the list archives, and cleaned grounds, cleaned the 02 sender
connection, etc, too many things to list here.
Some guys wrote that they run in open loop all the time (02 sensor
unplugged). If I went open loop I would find a way to safely hook up a wire
to the 02 sensor, then run the wire up front so I could monitor what the
engine was doing with a digital multi-meter. If you run a wire out the
engine cover, be safe and don't let any exhaust fumes into your van. Also
place the meter where it doesn't interfere with your driving and make you
crash your Van
I messed around with the AFM spring tension and found a spot where it runs
better. Again be careful, after one of my adjustments I got stuck in the
middle of a road because the van had no power. Run these tests where it is
safe.
Also I built a Digitool, so I can monitor the changes I made with the AFM
and the 02 sensor.The 'digitool version 1' I built is here under the Vanagon
section:
http://www.loam.org/vw/
Good luck, hope this is of some help,
Mark Ingalls
85 GL 1.9
>From: marcoux <smarcoux@club-internet.fr>
>Reply-To: smarcoux@club-internet.fr
>To: ingalls_mark@HOTMAIL.COM
>Subject: wanagon
>Date: Sat, 10 Mar 2001 15:29:30 +0100
>
>hi mark,
>I found gerry' vanagon's site yesterday.It's very interresting and
>ther's tons of info.
>over here in france we're just a few running wasserboxer,the rest cope
>with those tiny 1.6 turbodiesel.
>I just bought a 1988 synchro 3 months ago in germany(they have a
>lot),and it has catalyc and o2 sensor.It's a 2.1 liter engine.
>As I can get rid of the catalic ,do you have an idea what will happen
>with the engine management.I don't understand what you're talking about
>when speaking open loop or closed loop?does it mean that on morning
>engine startup the o2 sensor doesn't interact,
>to help the engine run better?
>I noticed that my engine is much more powerfull just after startup,then
>it gets real lazy(as if not much power).could I run with the o2 sensor
>unplugged?
>If you loosen spring tension on the afm,could the engine react better in
>the mid range?
>well lots of questions,I hope I didn't bother you,and that youcan be
>helpful.
>best regards from stefan
>
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