Re: O² Sensor Diagnostics

["Harold McElraft" <hmcelraft@xxxx>]

Dave

When the oxygen sensor is disconnected it tells the lambda computer 
to default to a fuel rich condition by sending a default frequency 
to the frequency valve. The sensor senses oxygen, that's all. It 
does not know rich or lean, etc. So, in order for the sensor to do 
its job correctly, everything else has to be working properly. 
Exhaust leaks can cause too much oxygen, misfires can cause too much 
oxygen, and vacuum leaks can cause too much oxygen and so on.

Based on your note I would say something is wrong because the idle 
is too high. It should be idling at 775rpm + or - 50. A slight 
fluctuation in the engine speed at idle is normal and represents the 
ideal oxygen level "hunt" by the lambda using the oxygen sensor 
voltage.

The only way to really know what the readings are is to do the 
exhaust analysis.

BTW ? a good way to use too much fuel and burn up the catalytic 
converter is to disconnect the sensor.

Harold McElraft - 3354

--- In dmcnews@xxxxxxxxxxxxxxx, doctorDHD@xxxx wrote:
> I notice that when I disconnect my O² sensor my car idles 
perfectly stable at 
> about 950 rpm. When it's connected the idle speed goes up and 
down, centered 
> at about 1000 rpm. Is this diagnostic of a specific problem? Is 
there a way 
> to test the O² sensor?
> 
> Dave
> 6530
> 
> 
> [Non-text portions of this message have been removed]