The exhaust system has to be air-tight for the O2 sensor to work properly.
Exhaust gas pulses can draw air in through cracks, which fools the O2
sensor.

Angus

Angus Gordon
Bainbridge Island WA

birdworks@gmail.com

On Mon, May 10, 2010 at 8:04 PM, tom ring <taring@taring.org> wrote:

> And a question.  I have had a very minor to major break in the exhaust for
> a
> few thousand miles.  The very minor was a lengthwise split about 2 inches
> from
> the head and extending for about an inch and a half.  That was around in
> somewhat patched to not patched for a couple cycles for about 5 thousand
> miles.
>  The major was the driver side forward cylinder.  Broke at the flange.  Bad
> mojo.  20 miles home.
>
> Patched with the nasty white exhaust paste wrapped with the high temp buck
> a
> foot exhaust wrap and then with steel fence wire with about 1/16 to 1/8
> spacing.
>
> Lasted for 150 miles, almost all I needed last summer.
>
> So the question - is proper/even back pressure a critical thing on these
> engines?  Because this thing is more balanced cylinderwise and just in
> general
> than I remember.
>
> tom
> K0TAR
>
> On 10 May 2010 at 21:27, tom ring wrote:
>
> > Just had a local private mechanic install a new exhaust on an engine that
> had
> > at least 1 broken stud.  He removed and welded a couple other support
> bits
> > during the job.  Replaced the oxy sensor with new.  Installed all new
> fuel
> > lines and covered them with the old outside protective plastic shrouds.
> >
> > I supplied the new exhaust kit and fuel line kit but nothing else.  He
> picked
> > up the oxy sensor and replacement studs as well as a few other gaskets
> and
> > bolts.
> >
> > Total bill - $330 including additional parts and shop.  I like Westside
> VW, but
> > this was a lot cheaper for 10 hours of work.
> >
> > He is in the Minneapolis metro if anyone is interested.  Contact me at
> the
> > shown email address.
> >
> > tom
> > K0TAR
> >
> >
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> >
>