Date: Tue, 13 Jul 2004 17:29:57 -0500
Reply-To: Larry Alofs <lalofs@RCN.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Larry Alofs <lalofs@RCN.COM>
Subject: Re: Running rich, O2 sensor says lean, exhaust leak?
Content-Type: text/plain; charset=us-ascii; format=flowed
What type of meter are you using? If it's not a high impedance digital
type, the meter will draw the voltage down and the reading will be low.
If your O2 sensor is sooted up or something that may be causing a weak
signal which tells the ECU to richen the mixture, producing more
soot...vicious circle.
I recently experimented with a sensor that I took out of our Golf a
while back because its signal was weak. After some preliminary heating,
I could get about 1 volt by putting the torch tight against the sensor
so the bright blue part of the flame was sending some fuel gas into the
sensor. When I pulled the torch away, the voltage dropped quickly to
nearly zero. This is said to be the proper behavior.
See this link:
> http://www.wps.com/LPG/o2sensor.html
gook luck, (Have you checked your fuel pressure?)
Larry A.
Craig Oda wrote:
> Karl,
> thanks for the tip.
>
> I don't have a spare electronic control unit. However, I'm not sure
> if the injectors are stuck open. At least, I hope that they are not
> stuck open. ;-)
>
> The big mystery for me is why the O2 sensor reads under 0.1 volts
> (really lean), even when there is an obvious condition of richness.
> Seems like the O2 sensor is telling the control unit, "I need more
> gas, I need more gas." Then, the injectors keep pumping gas into the
> system.
>
> When I disconnect the O2 sensor, the engine seems to run okay.
>
> If I disconnect the O2 sensor from the ECU, but connect it to a
> voltmeter, the O2 sensor still says that the engine is running lean,
> when in reality it is running rich.
>
> All I could think of was the exhaust leaking air into the system.
> However, maybe it is the engine ground.
>
> Keep the ideas coming.
>
> The van is sick. :-( And, that makes me sad.. :-((
>
> Regards,
> Craig
>
> On Tue, 13 Jul 2004 11:00:22 -0700, Karl Wolz
> <wolzphoto@worldnet.att.net> wrote:
>
>>Craig,
>>
>>Look for something else.
>>
>>You're using four times the fuel you should be. An exhaust leak will
>>affect your mixture, but not to that extent. I've driven home with a
>>broken exhaust - like fully separated - and not had the mileage affected
>>to a noticeable extent. Unless the dent is such that the exhaust flow
>>is pretty well closed off, you won't get this effect either.
>>
>>Sounds like your injectors are stuck open. That sounds like a CPU
>>problem. Do you have a known good unit you can swap in? Can you get
>>one? Perhaps from another listee?
>>
>>Karl Wolz
>>
>>
>>
>>
>>
>>>. Right now, I think it is air leaks
>>>into the system or maybe that dent.
>>>
>>>Any advice before I crawl around under the van and get dirt falling in
>>>my face, hair and eyes?
>>>
>>>-- Craig
>>
>
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