Date: Tue, 12 Sep 2000 21:19:55 -0400
Reply-To: Lawrence Johnson <larry_avery.johnson@SYMPATICO.CA>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Lawrence Johnson <larry_avery.johnson@SYMPATICO.CA>
Subject: Re: bucking/ what fix
Content-Type: text/plain; charset=us-ascii
"Joe L." wrote:
> I fought the fight for years using all of the standard fixes and
> tricks, all without success. One day last year I changed out a shot muffler
> and PRESTO! bucks are gone!
> No idea why but there it is.
Joe,
Just a wild idea. The Oxygen Sensor has only one signal wire and that signal is
in the 0-1 volt range. But that 0-1 volt is relative to the chassis ground. But
there is no direct ground connection between the Oxygen Sensor and the chassis.
The ground connection must be through the exhaust pipes and muffler. If the
connections are very rusty, this ground connection could be very poor. Worse, if
the exhaust components are joined by fiber gaskets, then you may have no real
ground connection. My guess is that you would have an intermittent ground and
the Oxygen Sensor voltage would be almost meaningless. The Digifant ECU would
make meaningless adjustments to the fuel injection timing/duration. Changing to
a new muffler may have given you a good ground and solved your problem.
-wish it were Phyday-
Larry
'86 Syncro Westfalia & Doublecab
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM]On Behalf
> Of Jason Willenbrock
> Sent: Tuesday, September 12, 2000 11:52 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: bucking/ what fix
>
> how many people have solved their bucking with the wiring harness? how many
> have solved it other ways? i replaced my temp sensor (the blue one, right?)
> and still after about ten hours of driving the bucking starts again. i stop
> and get gas and then the bucking comes back by the time the tank is half
> full. this happens religiously and i have driven cross country three times
> using this method. i guess filling it up give the ecu(?) a chance to cool
> down a little, but then in about 180 miles it commences. when road trip is
> over, a couple days rest brings her back to no more bucking, unless 10 hours
> of road time comes along. so what to do? install harness, replace ecu? i
> am rebuilding my engine will this have any effect? rather than replace a
> bunch of little parts, i would rather get to the source and be done with it.
> also, another symptom is, at start up the idle is too low and almost dies,
> then all of the sudden it surges right up to where it should be, is this
> caused by the same problem or something else?
> thanks
> jason
> 90 gl
> 82 westy
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
> Share information about yourself, create your own public profile at
> http://profiles.msn.com.
|