I'm with Tony, 27 MPG!! What am I doing wrong!!

Charles

----------
> From: Tony Moore <tony@moorelab.com>
> To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
> Subject: Re: 84 dont smoke no more (27 MPG??)
> Date: Tuesday, April 29, 1997 3:08 PM
> 
> Hi Earl,
> 
> Wow! 27 MPG!?! In a Vanagon???
> 
> Did I miss some of this thread? Is yours a deisel?
> 
> tony
> 
> ----------
> > From: Earl Smith <earlsmit@islandnet.com>
> > To: Multiple recipients of list <vanagon@lenti.med.umn.edu>
> > Subject: 84 dont smoke no more
> > Date: Tuesday, April 29, 1997 2:26 PM
> > 
> > 
> > >
> > >The story so far:  about two months ago a sudden increase (or should
it
> be a
> > >decrease?) in mileage from 27 mpg to 10 mpg. About a month ago,
increase
> of
> > >about
> > >ten thousand percent in black smoke emission.  (Sure discourages
> tail-gaters!) 
> > >Lots of excellent advice and suggestions from you folk, change of ECU
> and Temp.
> > >sensor 2, adjustment of AFM.  Minimal improvement.
> > >
> > >Friday, finally took it to a mechanic.  It took him three hours to
> figure out
> > >what was causing the problem and I think it was a great piece of
> detective
> > work.
> > >
> > >Wire coming from the O2 sensor on the 84 is a single lead that plugs
> into
> > >another
> > >lead coming out of the wiring harness.  That harness lead goes into
the
> > multipin
> > >connector.  For reasons known only to themselves, VW engineers made
that
> > harness
> > >lead a co-axial cable with the shield grounded.  Somewhere along that
> lead,
> > >inside the harness, the insulation around the inner wire broke and
> allowed the
> > >signal to ground on the shield.  
> > >
> > >The mechanic, Niel, took endless trouble to explain the operation to
me.
>  Seems
> > >at 600 degrees the O2 sensor generates a 0.5 volt signal to the
> computer.  Over
> > >that voltage indicates a rich mixture and the ECU decreases the fuel
> flow.
> > >Under
> > >0.5 volts indicates a weak mixture and the ECU feeds in more gas.  A
> grounded
> > >wire will produce a 0.0 voltage so guess what the ECU does?!!.  Niel
> simply
> > took
> > >apart the multipin connector and checked the voltage at the pin, then
> cut
> > >off the
> > >faulty lead and replaced it with a single wire lead.  Now ole Smoky
> purrs like
> > >a kitten and I am looking forward to 27mpg. again.
> > >
> > >
> > >
> > >