In a message dated 04/07/2008 9:49:47 P.M. Central Standard Time,
LISTSERV@GERRY.VANAGON.COM writes:

Van runs  terrific and all is well with the o2 sensor unplugged for over 1
year now. I  figured since I was placing an order with Bus Depot that I would
order a new  one to save on gas mileage. I ordered the good one, the Bosch that
I had to  splice the wires myself.?I got the old one out and?connected the new
one up  and bus runs like crap. Rough idling with black smoke. Same as old
sensor.  Unplug it and it runs perfectly.
Is there a way to check the new sensor to  make sure it's good or is there
any other reason for this behaviour? I do have  a slight exhaust leak at the
heads. Could that cause a poor reading at the o2  sensor?

My bus is the '91 Vanalong with stock 2.1 with 210 000 km and  runs really
strong without sensor. Should I simply leave it unplugged? How  much more gas
will it burn?

Gerry, you cannot have an  any exhaust leaks upstream of the OXY sensor.  It
will not operate  correctly.  Is that OXY sensor a BOSCH ?  Like the ones I
sell  >  from my _Vanagon  Items Forsale_
(http://members.aol.com/Fkc43/sales.htm)  webpage >  OXY sensor, 2.1 engine, BOSCH,  13913  -  $85.00.  Did you make
a  good & perfect continuity splice  ?  Next thing to check  is the green
wire.  Is it integral ?  Does the shielding end just  before the terminal end
where it joins the coupling to the OXY sensor.   That shielding must not touch
the terminal end.  That wire is what is  called a coaxial cable.  You need to
determine if it's good all the way  back to the ECU, see your Bentley manual for
testing procedures.  If those  things do not help then a complete diagnostics
of the FI system is needed.   The engine is supposed to run perfectly with
the OXY sensor connected otherwise  you will get piss poor gas mileage and you
don'T want that with high gas prices,  do you ?

Cheers,

Frank  Condelli
Almonte, Ontario, Canada
'87 Westy & Lionel Trains (_Collection for sale_
(http://members.aol.com/Fkc43/trainsal.htm) )
_Frank Condelli &  Associates_ (http://members.aol.com/Fkc43/busindex.html)
- Vanagon/Vanagon Westfalia Service in the Ottawa Valley
_Vanagon Stainless Steel Exhaust  Systems_
(http://members.aol.com/Fkc43/exhaust.htm)
_BusFusion_ (http://members.aol.com/BusFusion/bfhome.htm)  a VW Camper
camping event, Almonte, ON, June 12 ~ 15,  2008