Thanks for all the advice from everyone so far. I think I'm getting
somewhere.
I checked the voltage on the black wire and was getting nothing. Does
this mean bad O2 sensor?
All three wires are conducting as far as I can test them with my leads.

Roger

On May 27, 2005, at 5:39 PM, cmathis@houston.rr.com wrote:

> Roger,
>
> If the Sensor was spliced in I would start by checking the splices.
> One of the white wires provides power to heat the O2 Sensor element,
> the other white wire is a ground - I'm not sure if this terminates at
> the ECU or somewhere in the engine bay, the black wire is the signal to
> the ECU.  A lot of people use generic three wire sensors that have to
> be spliced to the connector.  Odds are fairly good one of those splices
> is bad.  If the splices are all good try disconnecting the black wire
> and checking the signal with the engine running.  If the O2 sensor is
> good it should be fairly steady around .5.  If the splices and sensor
> check out good your problem could still be in the wiring to the ECU or
> the ECU itself.  On the 1.9L it's all right there real close so
> checking is no problem.  On the 2.1 it is a bit more challenging.  At
> this point I'll readily admit I am out of my element and can't offer
> much beyond moral support.
>
> If it looks like the ECU is bad and the van is not an immediate need
> vehicle try to contact Darrel Bohler - there has been some traffic
> about him the past day or so on the list.  He used to repair ECU's for
> much much less than buying either a new or rebuilt unit.  He also
> modified ECUs to use a Digitool which is like a multi function meter
> that lets you check all the ECU input with one connection.  I got one
> from him shortly after I got my van and it is the best $100 I have
> spent on it.  He used to be on the list all the time but has not been a
> presence for a while now.  I think I heard he is still working.
>
> Chuck
>
> ----- Original Message -----
> From: Roger Van Till <rvantill@sbcglobal.net>
> Date: Friday, May 27, 2005 3:22 pm
> Subject: Re: ECU or O2 sensor ?
>
>> I looked closer at the sensor. It appears to be a newer one
>> spliced in.
>> Engine was replaced 3 years ago. Two white wires and a black one.
>>  The black one is disconnected to make it run better. Do I check
>> things
>> at the ECU or in the bay? Or run continuity checks the whole
>> distance
>> of the wire?
>> I really appreciate this kind of insight.
>>
>> Rog
>>
>> On May 27, 2005, at 1:42 PM, Chuck Mathis wrote:
>>
>>> Roger,
>>>
>>> I had a similar problem with my '85.  I'm betting it is an O2 Sensor
>>> problem rather than an ECU problem.  Before replacing the Sensor
>> though> check the continuity on the ground wire (one of the white
>> ones).> The '85 has the shielded green wire and the shielding is
>> grounded in
>>> the ECU connector.  On mine the ground splice had corroded so it was
>>> not functioning causing the O2 readings to be misinterpreted by
>> the ECU
>>> which caused power loss and stumbling when I hit the gas.  I
>> replaced> two O2 sensors before getting smart enough to check the
>> wiring.  An '86
>>> should have the three wire O2 Sensor so my guess is the ground
>> wire is
>>> not grounding.
>>>
>>> Chuck
>>> '85 Wolfsburg Westy - 'Roland the Road Buffalo'
>>>
>>>> Just added an 86 GL automatic to the fold. The PO's mechanic
>> (also a
>>>> PO) says it needs a new ECU.
>>>> The black wire to the O2 sensor was unplugged to fix the
>> problem. I
>>>> plugged it back in to see what the deal was. It loses power and
>>>> stumbles when you give it gas.
>>>> Unplug the wire and it's fine. Is this really an ECU problem or
>> should>> I try a new O2 sensor? His mechanic wanted to charge him
>> $800 for a
>>>> used unit!
>>>> The motor is a rebuild with 30,000 on it. Runs smooth, love it.
>> Can't>> say how old the O2 sensor is.
>>>> Thanks
>>>>
>>>> Roger VanTill
>>>> 89 Westy
>>>> 86 GL
>>>
>>
>>
>