AFR Meter Issue

[Strawdawg]

So far I have not been of any help

I can't come up with any plausible way that it could be that lean on the high side unless the sensor was mounted close to the open end of a collector and that is not the case.

In my experience with wb's I have found that they can get really flaky if the power and ground sides are not solid.  You might try connecting the power directly to the battery for both + and - temporarily and see if that has any effect at all.

Perhaps before you do that, you might switch the sensor back to the side that seemed to be giving a reasonable reading and see if it repeats and works again.

Also, you might try using the software logworks that comes with it and see if the log shows the same numbers as you are seeing on the unit, itself.

Normally, I have had problems with the analog outputs while the digital side kept working properly.

[cudabob496]

ya, that's what I was starting to think, some kinda electrical ground problem.
I assume the O2 detector has to ground somewhere?
Maybe when switching it, the ground is being lost.
or a short, which could cause the high reading?

[cudabob496]

are both weld bung holes exactly the same?

[cwestra]

are both weld bung holes exactly the same?

Yes.  They are identical.  I located the one on the driver's side about 8" back from the flange, while the one on the right side is a bit further back (around 16" or so).  Can't see that making any difference.  I will check the ground after confirming right hand still shows normal.  Thanks for all the help.  It's always something with these cars.

[Strawdawg]

try hooking straight to the battery temporarily

If the collector was open, it could make a difference being close to the end

[cudabob496]

Yes.  They are identical.  I located the one on the driver's side about 8" back from the flange, while the one on the right side is a bit further back (around 16" or so).  Can't see that making any difference.  I will check the ground after confirming right hand still shows normal.  Thanks for all the help.  It's always something with these cars.

What does it read when the O2 sensor is not in the exhaust pipe?
if the same 22, may be a grounding issue.

[brads70]

   I'm just curious as to what is the issue/problem? I'm stumped? 

[cwestra]

What does it read when the O2 sensor is not in the exhaust pipe?
if the same 22, may be a grounding issue.

The only thing I've done with the sensor out of the pipe was calibrate, and I've always gotten the correct calibration reading of 20.8 or 20.9.  I have not tried just running it outside to see what it reads.  I can certainly try.
  Does the fact that I can affect the reading (when installed in left pipe) by pumping the pedal (enriching manually) still suggest a possible grounding problem?

[cudabob496]

The only thing I've done with the sensor out of the pipe was calibrate, and I've always gotten the correct calibration reading of 20.8 or 20.9.  I have not tried just running it outside to see what it reads.  I can certainly try.
  Does the fact that I can affect the reading (when installed in left pipe) by pumping the pedal (enriching manually) still suggest a possible grounding problem?

Not sure. Why not contact the manufacturer to see what they say?

[Strawdawg]

The sensor is not grounded  via the sensor mount.  It is very important that the unit be powered by a good supply and a good ground that reflects battery ground.  I have seen cases where they would not work properly when trying to use a cigarette lighter power adapter due to either a low voltage supply or a poor ground.  Hence I asked about powering it directly to the battery to see if there was a change.  Given it worked once on one side and never out of two tries on the other, I am curious to see if it again works the other side.

Mounting too close to an open collector will often make the reading artificially lean but this usually tends to diminish around 3000 rpm.

[cwestra]

The sensor is not grounded  via the sensor mount.  It is very important that the unit be powered by a good supply and a good ground that reflects battery ground.  I have seen cases where they would not work properly when trying to use a cigarette lighter power adapter due to either a low voltage supply or a poor ground.  Hence I asked about powering it directly to the battery to see if there was a change.  Given it worked once on one side and never out of two tries on the other, I am curious to see if it again works the other side.

Mounting too close to an open collector will often make the reading artificially lean but this usually tends to diminish around 3000 rpm.

I just got back into town from being gone all week.  Tomorrow I'll try it again in the right pipe and see what I get.  Then I believe I will contact the mfr., cudabob, to see what they say.  Thanks again.

[Strawdawg]

One last suggestion that borders on black magic

Beyond hooking directly to battery as a test, remove the sensor, do the free air calibration again.  Leave the sensor connected to the harness rather than unplugging it.    Before screwing it into the bung with it still connected, twist the cable a few turn backward so that it straightens out as you screw it into the bung.

[cwestra]

possibly the pipe is not sealed & drawing in air

Turned out that's what it was.  I pulled the pipe, pressurized it slightly with compressed air, and sprayed soapy water on the weld.  Found several small pinhole leaks.  Difficult to feel or hear when the car was running but obvious when I was able to take a closer look.  Anyway, sensor now reads as it should on both pipes.  They really have to be sealed good in order to provide accurate readings.  Just thought I'd provide an update and officially close out this issue.  Thanks again for everyone's help.

[Strawdawg]

Lotsa people here that will tell you that cannot happen because the exhaust gas pressurizes the pipe but such will really screw up the O2 readings on new cars. 

Glad you figured it out!

[cudabob496]

Lotsa people here that will tell you that cannot happen because the exhaust gas pressurizes the pipe but such will really screw up the O2 readings on new cars. 

Glad you figured it out!

I assume, due to high flow, that it will draw the air in? Isn't that why some folks vent the crank case to the exhaust system, near the collector?