Arlen Holder wrote:
http://www.bild.me/bild.php?file=8572593obd01.jpg
RPM held steady at approximately 2000
O2B1S1(V)=1.275
O2B1S2(V)=0.760
O2B2S1(V)=0.665?
O2B2S2(V)=0.635G

This is the data you want to see, but if possible you want to see it as
graphs, because a lot of what you care about are trends and not just the
stock voltages. Your software also should be able to put lines on the graph
showing the nominal values.

However, since it's a BMW, you can guess that the nominal value is somewhere
around 1.0. High voltages indicate something running too rich, low voltages
indicate something running too lean.

So.. we look at bank one sensor one... it's running kind of rich, which is
bad... and then we look at bank two sensor one.... it is running super lean
if that voltage is to believed. So we have a problem.

Downstream on sensor two the value on bank 1 is kind of high, so you may be
getting the error being set due to that, but that's not your problem. Your
PROBLEM is that half the engine is running too rich and the other half is
running too lean (probably because the ECU is trying to compensate).

The FIRST thing that I would do would be to swap the upstream sensors from
side to side and see if the readings move from side to side. If they do,
you have a bad oxygen sensor. If they don't, you need to start looking on
the engine side for vacuum leaks and bad injectors.

You can put a new converter onto this, but it won't stay good for very long
until you sort out the mixture problems.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."