On 20 Aug 2018 17:10:50 GMT, Scott Dorsey wrote:

FIRST you need to look at the value coming out of the upstream oxygen
sensor. Is it within range? If so, the system is running locked and
the mixture is good.

If not, then deal with the engine running issue that is the real problem.

If the value coming out of the downstream sensor is totally out of range
or the pointer moves very slowly as the car warms up, then the downstream
sensor is likely bad.

If the value coming out of the downstream senor pretty much tracks the
value coming out of the upstream sensor, then the catalytic converter is
bad. You can gun the engine and watch the two graphs move and they are
almost exactly the same (because the converter is doing nothing and so
the composition of the input and output ARE almost exactly the same).

Here are the values coming out of the scanner just now, with the engine
warm, and with my foot on the throttle with steady pressure.

Which numbers look abnormal to you?
=========================
http://www.bild.me/bild.php?file=6121688obdcode00.jpg
P0132=O2 Sensor Circuit High Voltage BAnk 1 Sensor 1
P0430=Catalyst System Efficiency Below Threshhold Bank 2
=========================
http://www.bild.me/bild.php?file=9033313obdcode01.jpg
MIS=OK
FUE=OK
CCM=OK
CAT=OK
EVAP=NOT OK
AIR=OK
O2S=OK
HRT=OK
=========================
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
=========================
http://www.bild.me/bild.php?file=2946125obd02.jpg
RPM held steady at approximately 2000
O2B1S1(V)=1.275
O2B1S2(V)=0.750
O2B2S1(V)=0.720?
O2B2S2(V)=0.635G
=========================
http://www.bild.me/bild.php?file=5523137obd03.jpg
RPM held steady at approximately 2000
O2B1S1(V)=1.275
O2B1S2(V)=0.740
O2B2S1(V)=0.150?
O2B2S2(V)=0.635G
=========================
http://www.bild.me/bild.php?file=5766361obd04.jpg
RPM held steady at approximately 2000
O2B1S1(V)=1.275
O2B1S2(V)=0.740
O2B2S1(V)=0.720?
O2B2S2(V)=0.685G
=========================
http://www.bild.me/bild.php?file=9733573obd05.jpg
RPM held steady at approximately 2000
O2B1S1(V)=1.275
O2B1S2(V)=0.740
O2B2S1(V)=0.110?
O2B2S2(V)=0.660G
=========================
I realized I should probably record actual RPM so I added it to the mix
=========================
http://www.bild.me/bild.php?file=1876737obd06.jpg
RPM=3227
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.670G
O2B2S1(V)=0.630?
O2B2S2(V)=0.710
=========================
http://www.bild.me/bild.php?file=9131116obd07.jpg
RPM=3244
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.645G
O2B2S1(V)=0.680
O2B2S2(V)=0.570
=========================
http://www.bild.me/bild.php?file=8766702obd08.jpg
RPM=2226
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.780G
O2B2S1(V)=0.795
O2B2S2(V)=0.750
=========================
http://www.bild.me/bild.php?file=9305972obd09.jpg
RPM=2178
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.685G
O2B2S1(V)=0.285
O2B2S2(V)=0.640
=========================
http://www.bild.me/bild.php?file=3745618obd10.jpg
RPM=778
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.850G
O2B2S1(V)=0.695
O2B2S2(V)=0.765
=========================
http://www.bild.me/bild.php?file=2533891obd11.jpg
RPM=763
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.850G
O2B2S1(V)=0.120
O2B2S2(V)=0.725
=========================
http://www.bild.me/bild.php?file=8547378obd12.jpg
RPM=751
O2SLOC B1S12--B2S12--
O2B1S1(V)=1.275?
O2B1S2(V)=0.845G
O2B2S1(V)=0.650
O2B2S2(V)=0.745
=========================
Does anyone here know how to help me interpret those numbers?

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."

Scott Dorsey wrote:

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.

Oh, and I am assuming that your software is correct in enumerating them,
that O2B1S1 is upstream bank one and O2B1S2 is downstream bank one. Make
sure you trust your software either by validating it with a mirror or pulling
a wire from one sensor and making sure it shows up as pulled on the software.

What IS that questionmark? What does it indicate? If you had a plot you
could guess.
--scott


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

On 21 Aug 2018 07:56:52 GMT, Scott Dorsey wrote:

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.

I agree. It seems that the Cen-Tech item 60693 can do graphs so I'll look
at them tomorrow when I drive the vehicle warm again.

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.

Apparently, from my googling of how the oxygen sensors work, as you said,
the more "reducing agent" there is (e.g., a rich mixture), the more oxygen
diffuses from ambient to the exhaust gas, hence, as you said, that
generates a higher voltage.

If there aren't many hydrocarbons in the mixture (e.g., a lean mixture),
then there aren't any reducing agents for the oxygen to diffuse from the
outside air into the inside of the oxygen sensor, so it barely generates a
voltage.

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.

I agree with you that bank 1 sensor 1 is pegged at a high non-fluctuating
voltage of 1.275 volts, while bank 2 sensor 1 is fluctuating from about
0.110 volts to about 0.795 volts.

The two upstream sensors are brand new, the P0132 code indicates Bank 1
Sensor 1 has a "O2 Sensor Circuit High Voltage", which is true, since it's
steady at 1.275 volts.

If we assume the two upstream sensors are working properly, and if their
input voltages and heater circuits are correct, then that would indicate a
rich mixture - but - there are plenty of codes for rich mixtures - none of
which are indicated.

So I'm not sure what to make of the steady 1.275 volts on the bank 1
upstream lambda sensor - but your suggestion of switching the two upstream
sensors should help isolate whether it's a bad sensor from the factory or
something in the fuel mixture or input electrical circuitry.

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).

I agree that the downstream sensor output isn't all that useful until I
figure out why the upstream lambda sensors are indicating such wacky
dichotomy of very rich (bank 1) and not very rich (bank 2).

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.

Yup. I'll do that tomorrow in the daylight.

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.

Yup. Either it's really running rich, or the voltage to the sensor is bad,
or the sensor itself, even though it's brand new, is bad.

Switching the two upstream sensors should help eliminate some of those
choices.

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

Agreed. Here are some readings from today which I generated on the highway
before I read your post above (which repeats for today, basically, the
readings that you already commented on from the prior day).
=========================
http://www.bild.me/bild.php?file=9463821obd001.jpg
RPM 749
O2B1S1(V) 1.275
O2B2S1(V) 0.680 ?
O2B1S2(V) 0.830 G
O2B2S2(V) 0.715
=========================
http://www.bild.me/bild.php?file=5010400obd002.jpg
RPM 1468
O2B1S1(V) 1.275
O2B2S1(V) 0.095 ?
O2B1S2(V) 0.780 G
O2B2S2(V) 0.740
=========================
http://www.bild.me/bild.php?file=5797969obd003.jpg
RPM 2104
O2B1S1(V) 1.275
O2B2S1(V) 0.670 ?
O2B1S2(V) 0.755 G
O2B2S2(V) 0.565
=========================
http://www.bild.me/bild.php?file=3108371obd004.jpg
RPM 2182
O2B1S1(V) 1.275
O2B2S1(V) 0.675 ?
O2B1S2(V) 0.700 G
O2B2S2(V) 0.615
=========================

On 21 Aug 2018 08:00:03 GMT, Scott Dorsey wrote:

Oh, and I am assuming that your software is correct in enumerating them,
that O2B1S1 is upstream bank one and O2B1S2 is downstream bank one. Make
sure you trust your software either by validating it with a mirror or pulling
a wire from one sensor and making sure it shows up as pulled on the software.

What IS that questionmark? What does it indicate? If you had a plot you
could guess.

Hi Scott,

Thanks for that advice, which is good advice, and which I only received
just now, so I haven't been able to take you up on that test to confirm
what I would have assumed, which is the assumption that...
* O2B1S1 (I would assume is the upstream sensor for bank 1, cylinders 123)
* O2B1S2 (I would assume is the downstream sensor for cylinders 123)

* O2B2S1 (I would assume is the upstream sensor for bank 2, cylinders 456)
* O2B2S2 (I would assume is the downstream sensor for cylinders 456)

I'm not at all sure what you mean by using a "mirror" but it's easy enough
to disconnect a sensor, especially for the two upstream sensors which are
tucked away but accessible from the passenger side of the engine bay.

I have the owners manual for the Cen-Tech Harbor Freight item 60693 OBDII
scan tool, which I had borrowed from a friend. The "G" indicates a "graph"
is available, while the "?" indicates "help" is available.