Date: Mon, 22 Aug 2011 00:19:53 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: O2-sensor blues and more on '84 1.9L engine
Content-Type: text/plain; format=flowed; charset="UTF-8"; reply-type=original
re
When both halves on connector are joined, voltage is about 0.45 volts."
does this mean ..
when the two wires of the for 02 sensor signal is plugged together, engine
running,. and you are taking that reading, you get a steady .45 volts.?
that is a dead oxygen sensor normally.
fwiw ..
grounding the 02 signal wire is not something I would ever do, pretty much.
Scott
www.turbovans.com
----- Original Message -----
From: "John Lauterbach" <jhlauterbach@BELLSOUTH.NET>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Sunday, August 21, 2011 5:18 PM
Subject: Re: O2-sensor blues and more on '84 1.9L engine
> Dennis,
>
> Thank you for your help. Shorting the engine end of the O2-sensor
> connector to ground makes the engine decrease RPM, run rough, and
> exhaust to smell rich. Voltage on sensor end of connector is about 0.20
> volts. When cable is not shorted, voltage goes up a bit to about 0.25.
> When both halves on connector are joined, voltage is about 0.45 volts.
> However, most of that voltage is present on the engine end of the
> O2-sensor cable. Does this mean something in the ECU is wrong?
>
> John
>
> On Sun, 2011-08-14 at 22:29 -0400, Dennis Haynes wrote:
>> There is a way to test the O2 sensor system for response. With the
>> engnine warm and running, short the O2 sensor lead to ground. The engine
>> should go rich. You can use the voltmeter to confirm this as the O2
>> sensor voltage should go up. You want to see ~.8 to 1.0 volt or more. Now
>> connect the sensor lead to voltage source/ This should drive the ECU to
>> make the mixture lean and this will make the O2 sensor voltage drop.
>>
>> As the ultimate test reconnect the O2 sensor. Measure the voltage on it
>> and see if it is fluctuating. If it is then it it is working and your
>> perceived richness may actually be something else such as an ignition or
>> lean cylinder miss fire or maybe something more cylinder such as valve
>> problem.
>>
>> Dennis
>>
>>
>> -----Original Message-----
>> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
>> Of John Lauterbach
>> Sent: Saturday, August 13, 2011 11:47 AM
>> To: vanagon@GERRY.VANAGON.COM
>> Subject: O2-sensor blues and more on '84 1.9L engine
>>
>> First, thank you to one of the list gurus who suggested checking on
>> shorts between O2-cable and its shield. I had one of my own causing.
>>
>> When the O2-sensor is connected and I measure the voltage between the
>> connector and engine ignition control module heat shield, I am getting
>> around 0.46 volts with engine warmed up. Voltage is rather stable with
>> engine at idle. Am I in the ballpark?
>>
>> With O2-cable unplugged, resistance between connector and ground on cable
>> to O2-sensor is infinite. Resistance between other connector and ground
>> on cable to ECM is 173000 ohms.
>>
>> I am not sure what I am missing, but engine runs well, but is running
>> very rich.
>>
>> John
>>
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