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Oxygen Sensor Testing

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Old Apr 30, 2010 | 06:50 PM
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Default Oxygen Sensor Testing

I noticed that I my gas mileage has been going in the tank for sometime. So I removed each of the oxygen sensors and noticed that the front sensor had carbon buildup on the sensor and the rear sensor was bright and clean.

I then proceeded to test the oxygen sensor by following a video on You Tube. I heated the rear sensor and within ten seconds I was receiving .6 mv and when I removed the flame it dropped to less than .1 mv in a couple of seconds or less.

I tested the front sensor and the highest I could get the sensor was .4 mv, which would indicate that the sensor is in a lean condition and calling for extra fuel to the front cylinder.

I then proceeded to travel to my local steelers to purchase a new oxygen sensor. I proceeded to test the sensor prior to placing into the bike. When I heat the sensor the highest mv reading I can get is .04 mv; so now I'm wondering if I'm doing something wrong or could they have sold me a bad brand new oxygen sensor? Seems to me oxygen sensors are pretty tough and last for some time.

Possibly there is some error in my testing mythology.
 
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Old Apr 30, 2010 | 06:58 PM
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When I took my oxygen sensors out of the scoot to fix my pipes, I cleaned the sensors with a wire brush and popped them back in. One was a slightly different color than the other. You could have saved some cash by going to an auto parts store and buying the same bosch sensor that HD uses, just so you know for future reference. Bosch 12028 at Advance auto would save you $20
 

Last edited by dawg; Apr 30, 2010 at 07:00 PM.
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Old Apr 30, 2010 | 08:01 PM
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Dawg,

Thanks for the help. I'm going to rtn the sensor back to the dealer and run over and get one from a auto part store.
 
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Old Apr 30, 2010 | 09:09 PM
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For $40 total, grab two. ;-)
 
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Old May 1, 2010 | 06:07 AM
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I am thinking that the test is a bit flawed , and here's why.
The O2 sensor is a "signal generator" based on "chemical reaction" and heat makes them read quicker.
This is why most cars have heated O2 sensors , to make them read faster and more accurate.
Now the flaw would be that you're reading the chemical reaction of the torch , not air/gasoline mix from the engine.
Logically , the front sensor would look darker "naturally" from being in the colder pipe than the rear.
This would also make the rear sensor a bit more "naturally" accurate than the front sensor.
That being said , if the sensors are heated , the front sensor heater might be bad , thus the sensor is bad.
A new sensor would be the only thing to try , unless you could read the sensors "on the fly".
I repair cars for a living , and we can read the sensors "live" on a test ride for comparison.
Of course , the front cylinder might just be running too rich...........
Mick
 
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Old May 1, 2010 | 01:55 PM
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Appreciate the insight. I took the sensor back to HD & went to OReily & purchased the sensor. After getting it home I was able to produce 600mv with no problem and would drop to less than 100 mv in about two seconds. I believe the one from the dealer was bad. I talked with my dyno tuner and he confirmed that the oxygen sensor should not have soot on the sensor unless the cylinder is running rich. We'll see after replacing the sensor.

Originally Posted by Mick
I am thinking that the test is a bit flawed , and here's why.
The O2 sensor is a "signal generator" based on "chemical reaction" and heat makes them read quicker.
This is why most cars have heated O2 sensors , to make them read faster and more accurate.
Now the flaw would be that you're reading the chemical reaction of the torch , not air/gasoline mix from the engine.
Logically , the front sensor would look darker "naturally" from being in the colder pipe than the rear.
This would also make the rear sensor a bit more "naturally" accurate than the front sensor.
That being said , if the sensors are heated , the front sensor heater might be bad , thus the sensor is bad.
A new sensor would be the only thing to try , unless you could read the sensors "on the fly".
I repair cars for a living , and we can read the sensors "live" on a test ride for comparison.
Of course , the front cylinder might just be running too rich...........
Mick
 
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Old May 1, 2010 | 01:57 PM
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Originally Posted by dawg
When I took my oxygen sensors out of the scoot to fix my pipes, I cleaned the sensors with a wire brush and popped them back in. One was a slightly different color than the other. You could have saved some cash by going to an auto parts store and buying the same bosch sensor that HD uses, just so you know for future reference. Bosch 12028 at Advance auto would save you $20
Dawg,

I purchased the sensor the cross reference sensor. I did notice that it's about an inch longer than the HD sensors, it seems as long as a wide band sensor but it of course is not. Seems that Bosch must make the short ones special for HD. Also, the connector is different; have you had to change these connectors out and if so can you give me some insight?

Thanks,
 
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Old May 1, 2010 | 03:34 PM
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You can take the connector off the old one and put it on the new one.
 
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Old May 1, 2010 | 04:16 PM
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Yes, as WI Bob suggests, (and my ASE master tech also) replace in pairs!
Tenn.Vol.
 
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Old May 1, 2010 | 05:05 PM
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Originally Posted by TexasVet
Appreciate the insight. I took the sensor back to HD
No hassle returning it?
 
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