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I have a car BMW e46 318i 1995 ccm with engine n42 (143 hp) made 2004 / Jaunuary.
When analyzing OBD data with Konnwei KW850 diagnostic computer, I checked the fuel mixture preparation. I need help with one piece of information.
A diagnostic computer displays "datastream", where they are basic informations on fuel preparation. In total, you will see 3 data, 1 informace for "Long term fuel trim",
and 2 informations for "Short term fuel trim" ==> here is an example:
Short term fuel trim - bank 1 === 0.0% (I understand this information)
Long term fuel trim - bank 1 === 3.1% (I understand)
Short tern fuel trim - bank 1 - sensor 2 = == 99.2% (I do not understand).
What does mean Short term fuel trim for Bank 1 - Sensor2 with 99.2%??
Thank you.
 

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Maybe since you have a 4 cylinder you only have 1 O2 sensor or it's unsupported
 

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The Bank 1 Sensor 2 would be the after CAT sensor.

The ECU can use it to adjust the fuel trim.

Rear O2 Sensor Fuel Trim
The rear oxygen sensor, located after the catalyst, is used for fuel trim corrections on some OBD-II vehicles. By virtue of its location,
the rear sensor is generally protected from high temperatures and much of the contamination that affects the front oxygen sensors.
In addition, the rear sensor sees exhaust gases that are equilibrated ***8211; they have already been converted by the catalyst so that there
is very little residual oxygen. This allows the rear sensor to respond to much smaller changes in exhaust gas oxygen content.
In turn, it then possible for the rear sensor voltage to remain near the 0.45 volt switchpoint. This characteristic allows the rear sensor to be used for fuel control.


This link will download a Baum Tools Fuel trim document with more info:
www.bimmerfest.com/forums/attachment.php?attachmentid=303041&d=1322673583
 

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I have a car BMW e46 318i 1995 ccm with engine n42 (143 hp) made 2004 / Jaunuary.
When analyzing OBD data with Konnwei KW850 diagnostic computer, I checked the fuel mixture preparation. I need help with one piece of information.
A diagnostic computer displays "datastream", where they are basic informations on fuel preparation. In total, you will see 3 data, 1 informace for "Long term fuel trim",
and 2 informations for "Short term fuel trim" ==> here is an example:
Short term fuel trim - bank 1 === 0.0% (I understand this information)
Long term fuel trim - bank 1 === 3.1% (I understand)
Short tern fuel trim - bank 1 - sensor 2 = == 99.2% (I do not understand).
What does mean Short term fuel trim for Bank 1 - Sensor2 with 99.2%??
Thank you.
You only have one Bank. Bank 1. The fuel trims on Bank 1 are ok. Not perfect but not bad either. For "Banks" read "exhaust manifolds". Six cylinder engines have two exhaust manifolds. Bank1 and Bank2. Bank 1 is the first three cylinders and Bank 2 the second three cylinders. You have 4 cylinders and only one exhaust manifold: Bank 1.
 
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