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YOUR RESEARCHoxygen (lambda ) sensor and high fuel consumption
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Disconnect negative lead
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Suggestion
Then do a ECU/DME reset by disconnecting the negative lead on the battery for a few minutes.
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Suggestion · Original poster
Is there a prescribed interval to replace the oxygen sensors?
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Suggestion
Then do a ECU/DME reset by disconnecting the negative lead on the battery for a few minutes.
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First some more general questions:
Is there a prescribed interval to replace the oxygen sensors? Or is it that you just drive them till the ECU produces a fault code and/or throws a CEL?
Is there a difference in wear for the sensor in front or behind the catalytic converter? Do you replace them all 4 or in pairs (left + right) when one of them is toast?
In case one sensor is not working very well. Is there a broad margin of error before a fault code is generated.
*** EDIT: The rest of my post was related to my fuel consumption and the possibility that it could be related to a worn out oxygen sensor which would let the engine run to rich without producing a fault code. However after some research I think 17-19mpg for my 2002 C2 tiptronic falls well within spec considering my driving. The above general questions however still stand
***
If you are getting 17-19mpg then you need to drive harder! That being said, the O2 sensors do not have a predicted life because there are so many environmental variables involved. However, they are constantly monitored by the ECU/DME and are rather sensitive. So most just wait until a code pops up for an O2 sensor and the CEL comes on before changing. Generally, when that happens it is best to replace them in pairs, i.e., both pre-cat or both post-cat sensors, not all four. Then do a ECU/DME reset by disconnecting the negative lead on the battery for a few minutes. This puts the ECU/DME back to basics, then in a re-learning mode. Drive on....
The ideal way to do this would be to have a flex fuel sensor that integrates to the CAN bus which the Cobb AccessPORT can listen to.
Short of that, you'd need a standalone.
Whenever you floor the throttle pedal oxygen sensor signals are ignored and lambda goes to 0.85 in order to get max power.
However, when not flooRing it the Autobahn is ideal for adapting the part throttle area for speeds between 140-160 kph cruise speed.
Well meant advice: Make sure tyre pressures are as indicated on the sticker before you hit the high speeds (before you start your travels , really).and stay below 120kph when heavy rain comes down to avoid aquaplaning....
