Winky Blinky vs O2 Sensor question

[DennisG01]

Looking through my service manual, at the list of "codes" that can be produced/read:

--There doesn't appear to be one for the O2 sensor.

There is a note that says: "No diagnosis function and it's code for Oxygen density sensor fail. 6 cylinder operation will be held if the sensor failed"

Does this mean that the engine would only run on 5 cylinders?

[Sequoiha]

It means the ECM has no logic to monitor the o2 sensor and doesn't monitor it, yet it does dictate injector pulse width. You can still test its function with a DVOM,

[boscoe99]

Is this a Yamaha SM you are looking at? If so, what is the document number and page number that you are finding this information in?

[DennisG01]

Sequoiha - I think I remember testing my spare O2 sensor by doing a resistance test, and I think I did a flame/torch test and saw quickly changing results on the DVM. Although, I don't recall the exact procedure - I'll have to look that up again.

Boscoe - yes, it's a Yamaha SM. It's Lit-18616-01-61, page 8-11. I believe this is for a model year or two earlier than mine. I have a newer SM at the boat (about 500 miles away, right now - but will be there early next week) - but to be honest, I'm not sure it's any different?

[rodbolt17]

the flame test is a teat on a boar hog.

there is another bulliten that better tests the O2 sensor output voltage.

the 3.1L uses CCS unless it is a VX model.

means it runs on 5 or 4 cylinders below about 1800 RPM and above about 600 RPM.
IF the ECU see's an open or short on the O2 sensor feedback it will lock out CCS fix fuel rich at low speed and lean above 4000. do not run above 4000.

[DennisG01]

So the flame test isn't a super-reliable test. Got it - thanks.

It's an SX model.

Would there be any indications that it's running lean (if I'm over 4,000)?

Do you happen to have a reference or instructions on that better way to test O2 sensor?

[mjm-1957]

Is there any way to disable the ccs system? I have a 99 225 0x 66 and love the motor except for the ccs.I would be more than willing to forego any supposed fuel savings this system is supposed to provide for a smoother running engine.Thanks

[DennisG01]

I'm going to plan on cleaning the O2 sensor when I get to the boat. I also read about something called a "sniffer tube"? Removing and cleaning that? I assume it will make sense once I see it in person?

The part that has me worried, in regards to what Rodbolt said about running lean, is... How would I know if that's happening while the engine is running? Are there any telltale signs? Or do you just make it habit to test the O2 sensor from time to time?

Rodbolt, if you're reading this, can you please elaborate on the "better test method" you referenced? Is it different than what the SM says - testing for voltage at idle? It talks about a "lower limit" of .3V. Is there an upper limit (less than 1V)?

[nickmo12]

You can buy or make a test harness that connects to the o2 sensor. It enables you to monitor voltage at all speeds.

[DennisG01]

Oh. I can't just use a Volt Meter? Sorry - probably dumb question, but I'm not there at the engine to look at it.

[99yam40]

will need to get the meter leads in contact with the wires to read them.
not good to put holes in wire insulation, thus the adapter to Tee in without damage.

might be able to back probe the connectors thou

[DennisG01]

Ah. Gotcha. That makes sense. Yes, I agree - not a fan of putting holes in wiring, especially wiring that's around salt air. There's no reason to give corrosion a helping hand.

[boscoe99]

Send me your email address via PM and I can send you some literature with respect to testing the sensor.

Don't over look the electrical connections. The output voltage of the sensor is very low. You can't afford for there to be any excessive resistance in the circuitry.

[DennisG01]

PM sent. Thanks!

I will check connections - pull, clean, re-tighten. Along with inspecting what I can for corrosion that may have wicked under the sheathing. Overall, the engine is pretty clean and I spray it with Boeshield.

[DennisG01]

I removed the gray/black plug (If I understand things correctly, this would only cause a rich condition... and it did smoke more than usual) and got between .3V to .6V at idle and at 3,000RPM's. This was just sitting at the dock - I'm waiting for the sensor harness to come in so I can do it properly under load.

I pulled the O2 sensor out and it, along with the draw tube, were both very clean. But I still soaked them and carefully removed what little carbon there was (although none was around the tip/holes of the O2 sensor and none was inside the draw tube).

I reinstalled with a new gasket kit and did the test a second time, just for kicks, and of course got the same numbers.

One thing I thought that was weird... This is a picture of the draw tube. It looks different than the one in the service manual. It looks similar to the one in the material that Boscoe sent me, but there wasn't a gasket/o-ring. Nor was there a gasket/o-ring in the kit that I got from the Yamaha dealer (using my model/serial number). However, the two bevelled ends of the tube do seem to match up with their "mating surfaces". Anything to worry about?

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