So I took a trip on the Dulles Toll Road with my laptop hooked up. I started logging after I came up to speed leaving the starting toll plaza, and shut the logging down as I was exiting to the end toll plaza, somewhere around 11 miles. Then I took on additional reading when I reached the parking lot.

I also took some STFT readings while driving. They were mostly slightly negative in the -.8 to -1.6% range, with Bank 2 generally lower.

So here are the results from 3,617 data points:

Sensor /Average Voltage
B1S1 /0.4327
B1S2 /0.5637
B2S1 /0.5908
B2S2 /0.2299

Condition/ LTFT B1/ LTFT B2

Start of freeway drive/ 0%/ 1.6%
End of freeway drive/ 0%/ .8%
After 3 minutes stop/go/ 0%/ 1.6%

The spec for the S2's is >.485 volts.

Assuming I am reading this data right, I am puzzled why B2 would be running slightly rich according to the sensor, but have a positive LTFT ???

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe