Mike,
This is interesting information.
I have examined the green wire which goes
back to the ECU. The green wire on my
Vanagon does not have a braided shield
around the wire.
I have performed all of the pin to pin
continuity tests as per the Bentley for the
02 circuit and all tests meet specification.

What effect does not having a shielded green
signal wire have on the system??

Thanks

JB

On 2/9/09 6:27 PM, "Mike Collum" <collum@myfairpoint.net> wrote:

> The "Green" wire in the 02 sensor circuit is the "Signal" wire and it
> resides within a shield.  The green wire and the shield must not short
> together.
>
> For the shield to work as a shield it must only be grounded at one end
> (the ECU end).  If it makes ground anywhere else it's no longer
> providing shielding.
>
> The wire from the 02 sensor itself, up to where it connects to the green
> wire, isn't shielded.
>
> Mike
>
>
>
> Jerry wrote:
>> I hope for some much needed advice on this problem.
>>
>> I have an 88GL which actually meets the electrical
>> specs of an 87 by looking at the Bentley wiring diagram.
>>
>> My problem is this:
>> When the engine is cold it seems to run fine.
>> At highway speeds all is well until the engine
>> reaches operating temperature.  After the engine
>> reaches operating temperature it begins bucking
>> during upshifts and throttle speed increase. When
>> I push on the throttle to increase speed there is
>> a significant hesitation.  The engine speed will
>> finally increase to meet the fuel demand and throttle
>> response. Engine speed above 2500 seems ok.  Throttle
>> increase above 2800 RPM seems normal(no hesitation).
>>
>> I am thinking this is an Oxygen Sensor GROUND problem
>> but am not sure.  I have read all the posts concerning
>> oxygen sensor grounds and I have questions.
>>
>> Where does the oxygen sensor ground(green wire)?
>> Does it go to ground at the #29 chassis ground by the ECU?
>>
>> I have a three wire oxygen sensor.  Where does the brown
>> wire ground from the oxygen sensor(chassis harness). The Bentley indicates
>> a ground at #12 ground in engine compartment(left). The brown wire
>> on my 2.1 02 sensor goes into the engine compartment harness which
>> runs along the front of the engine deck. I cant tell
>> that the brown wire goes to ground from the 02 sensor.
>>
>> I have cleaned and reinstalled all grounds, however
>> I combined some of the grounds at two locations on
>> the left engine firewall.
>>
>> I have a 2.1 Boston Engine installed in MAR 2008
>> New AFM
>> New Idle Control Unit
>> New 02 sensor
>> New Distributor and Hall sensor
>> New ECU
>> New Evaporative control canister
>>
>> This problem has got me down!
>> As you can tell I've replaced just about all components.
>> I also have the harness installed between the AFM
>> and original chassis harness.
>>
>> Thanks for any advice.
>>
>> JB 88 GL Guido
>> New spark plugs, cap, rotor and wires
>> New fuel injectors and fuel lines
>> New fuel pressure regulator
>>
>>
>>
>