oxygen sensor test

[ROBTEA56]

have a question about the test in the factory manual for the os sensor. it say,s to hook up volt meter between the black and gray heet it and should read 0.6v any one done this test i don,t know how it can reed voltage when not hooked up.

[boscoe99]

Think some more about the sensor and what it does.

If you apply a voltmeter to battery terminals it will indicate a voltage. Even though it is not hooked up to any thing.

[ROBTEA56]

os sensor question

boscoe thanks for the reply . but the question is the os sensor reads what i know when a volt meter is hooked to a battery it reads the battery,s , voltage but in this test were doe,s voltage come from. and do you know test pr for the sensor . can some one help thanks again.

[Sequoiha]

the O2 sensor has a pezio electric component in it, it is a voltage generator with heat, as you heat it up with a hand held propane torch, (plumbers torch) and remove the heat it should produce voltage, the voltage should span .02v to .08 v, the range is from .01 to 1.0v DC, it gets very hot, so be sure to heat up plenty, just dont melt it,, you also want to test the other set of wires to make sure there is good continuity,,,,

[boscoe99]

The type of oxygen sensor used in a Yamaha motor creates its own electrical voltage.

Do a Google search and you will find more information as to how they work than maybe you want to know. For instance

LBCC Automotive oxygen sensors

The procedure to test a Yamaha O2 sensor is in the applicable Service Manual.

Here is some Yamaha information that will help you better understand this component.

Oxygen (O2 ) Density Sensor
The O2 sensor used on the Yamaha fuel injected engine is a four-wire heated sensor. One wire is the O2 signal, one wire is the sensor ground, and
the other two wires supply operating voltage for the heater element. The sensor must be hot (200°F+) before it will function properly. The
advantage of the electrically heated O2 sensor over a one or two wire sensor is that it warms up quickly and remains hot, even at idle. Another reason for using an electrically heated O2 sensor is the location of the sensor. The sensor is located in a cavity at the end of a blind hole passage, which means exhaust does not flow through it. Proper sensor operation depends on the
exchange of exhaust gases in this passage. The sensor cannot be located directly in the exhaust passage because it would pick up too much of
the incoming fuel charge while exhaust scavenging is taking place.

The O2 sensor has a hollow center element made of a ceramic material (Zirconia). Two platinum electrodes make up the inner and outer surfaces of the center element. The sensor is constructed so that the inner surface is exposed to outside air and forms the positive (+) terminal of the sensor. The platinum coating on the outside of the element forms the negative (-) terminal which is exposed to the exhaust gases. An electrical signal is generated as a result of the interaction between the inner electrode exposed
to outside air and the outer electrode exposed to exhaust gases.

[ROBTEA56]

*** they do esist

cool thanks to all more ifro then i need but thank you. it doe,s make volt,s now i know why the darn thing coast so much will redo my tests again thank s to all

[rodbolt17]

the flame test in the manual is a teat on a boar hog at best.

take that section out of the manual and toss it.
DO NOT rely on the flame test.
did I mention its a TEAT on a BOAR hog?
there are at least 3 tech bullitens on running tests for the O2 sensor.

I have seen the sensor pass the flame test and FAIL the running test.

[Sequoiha]

You are somewhat correct Rod, but it is a good initial inspection to determine if you need to go buy another one or not,, if the heater circuit is open or if it does not produce any voltage at all. just another tool in our arsenal, by no means is it meant as the only test,,,

[rodbolt17]

I have seen to many pass the flame test and fail the running test and a few fail the flame test and work perfectly running.
its also why there are at least 3 tech bullitens on running output test.

if the heater circuit is bad why bother flame testing?

[boscoe99]

So, of the service manual test and the three technical bulletins, what is the correct way to bench test the sensor?

What is the running test? How is it performed and what are the pass/fail criteria?

Or, did Yamaha simply give up after four documents (SM and 3 bulletins) regarding the testing of the device?

God forbid that Yamaha would ever issue a revision to a document to correct an error or to include an omission.

[rodbolt17]

over time Yamaha found the flame test not very accurate.
that's why there are running tests to properly observe O2 sensor voltage.
one is at idle gear case submerged and engine at operating temp.
with the air box removed and the engine at normal temp cover the #1 cyl idle air bypass hole with a finger.
O2 sensor voltage should rapidly climb above about .8V.
remove the finger and it should drop to about .3V then start scaling between about .35 and about .65 V.
the other is a constant run at about 3000-3500 RPM and watching the O2 sensor voltage.
should scale in the .35V range.

[FabricGATOR]

They are running tests to properly observe O2 sensor voltage.
one is at idle, gear case submerged and engine at operating temp.
with the air box removed and the engine at normal temp cover the #1 cyl idle air bypass hole with a finger.
O2 sensor voltage should rapidly climb above about .8V.
remove the finger and it should drop to about .3V then start scaling between about .35 and about .65 V.
the other is a constant run at about 3000-3500 RPM and watching the O2 sensor voltage.
should scale in the .35V range.

cover the #1 cyl idle air bypass hole with a finger.

Where is the idle air bypass hole? Is it the 4-5mm hole in the butterfly plate?


Thank you,

[rodbolt17]

yes, that is the idle air bypass.
as ox66 does not have an isc valve you must allow air someplace.

that's why the shutter screw is NOT called an idle speed screw.

[RickoVenter]

Has anyone here got the O2 sensor scaling map for the OX66?

thanks

[boscoe99]

Has anyone here got the O2 sensor scaling map for the OX66?

thanks

What makes you believe that one exists?