Fuel Line Hose/Primer?

[99yam40]

I believe you still have not posted what the reference voltage was at the IAT sensor.

Where all did you measure the reference voltage at?

[rodbolt17]

the O2 sensor has NO ref voltage.
it has two white wires,power and ground for the 12V heater circuit.
the two gray wires are output to the ECU based on avalible oxygen in the sensor.
this voltage is self generated based on a chemical reaction.
can actually be recreated with that useless flame test.

YOU CANNOT do an ohms test on any loaded(hooked up) device and NEVER EVER with power applied.

what meter leads are you placing where when doing your 5V ref test?
and I am still waiting on your answer to how the engine would react to bad /incorrect reading Coolent and intake air temps?

now Ill toss in another,open circuit 5 V high, or closed circuit, output 0v, what happens to the motor?
idle speed?
timing?
can or cannot top speed be reached?

[nola0000]

99yam40...

There are only two wires on the IAT sensor(both black with yellow stripe) so I have no idea where I should be checking reference for that. Is it one of those wires to ground?


rodbolt17...

The reference voltage I was talking about was at the TPS. I set my meter (Extech 22-816) to DCV, pushed some sewing pins into the TPS-motor harness from the rear and clipped the red meter lead on the pin in the red wire and the black meter lead on the pin in the orange wire. Meter said 5.05V.

The ohm test I did on the O2 sensor was with both sensor harnesses unhooked and key off. I also tested it hooked up with the key off for good measure.

You keep mentioning coolant temp sensor. I dont have a bad coolant temp sensor. That sensor tested good. IAT test failed.

Youre really making me work . I imagine that the engine reads the outside temperature and adjusts the air/fuel ratio because air is denser at different temperatures which would throw off the ratio if it couldnt read it. No?

Not sure I understand your second quiz question.

[rodbolt17]

the reason I keep mentioning both is::: they both work IDENTICALLY.
they are NOT interchangable.
one of the blk/y wires has a 5v to ground potential,then the sensor is a simple variable resistor, the other blk/y wire is a ground path internal to the ECU.

the O2 sensor I really dont like to place in the engine sesor group.
its a 4 wire O2 sensor.
it has a heater internally.
until it gets over about 150*F it wont work correctly.
to aide in temperature stabilization it has a heater.
the output is in millivolts fed to the ECU.
as less O2 is observed by the sensor element the voltage output goes high,max is about 9.9mV.
as the O2 in the sensor goes higher the sensor output voltage goes lower,about 1.3mV max.
typically sensor output at 3000 RPM in the water unrestrained will rapidy scale between about 3.5mV and 6mV.
its a fuel trimmer.
its all about the 14 parts air to 1 part fuel at se*****l.
at 25*F air temp the air is very dense and contains more O2 molecules therefore requireing more fuel.
in the above scene the engine would run rich and top speed at se*****l could be reached.
same with the coolent temp sensor.
but remember the opposite is also true.
if any sensor,other than the O2,ATC and APS becomes dissconnected(open circuit) the base timing locks to 7*BTDC and engine idle speed increases to about 1100 RPM.
depending on the ,timing may or may not advance and top speed may or may not be reached.
same happens if a sensor shorts.

in the case of the IAT, ECU defaults to 41*F and O2 sensor feedback is fixed, at se*****l top speed could be reached,may get rich at higher altitudes.
no affect on fuel control,idle speed is normal.

the CTS,open or short,timing is fixed at idle at 7* BTDC will advance but not retard lower,idle speed increases ECU defaults to 4*F,fuel injection isnt increased or decreased for acceleration or deceleration(no accelerator pump or dashpot effect),O2 sensor feed back is fixed, top speed can be reached.

now to the O2 sensor.
if NO signal is recieved idle speed decreases and top speed cannot be reached.
fuel is fixed rich at low speed and lean above 4000 RPM.
DO NOT RUN ABOVE 4000.
the above is a direct quote from yamaha not me.

there are NO codes associated with O2.
none,no codes,alarms or anything until it goes POOF.
and thats why I hammer so hard on O2 sensor output voltage testing.
it will also give an indication of what the heck is going on with the motor.

going back to what I consider a sensor, on the air or coolent, that sensor is a throttling valve.
remember voltage does NOT flow and is a simple measure of electrical pressure between point A and point B.
as the temp increases the valve opens,as temp decreases the valve shuts.

[nola0000]

So what is the best way to test the voltage O2 sensor? Or check the health of your O2 sensor?

My idle is fine, between 7-800.

Still dont understand the discrepancy between the readings Im getting on a brand new part not being in sync with the service manual specs. Should I check for that 5V ref between one of the black/yellow wires and ground on the IAT?

[rodbolt17]

best way to test the O2 sensor output,go by your friendly yamaha dealer that you spend a few coins with and ask for the tech bullitens concerning OX66 O2 sensor testing.
disregaurd the flame test one


I have seen it pass the flame test yet not work on the motor or not pass the flame test and work on the motor.
this O2 sensor isnt cheap.

and, bingo .

[nola0000]

I havent spent any coins at any dealer yet. Didnt plan to. I try to fix things myself because I like to learn and Im a DIYer. Is there an online resource for these tech bulletins?

[99yam40]

dealer is all I have heard as a source.

You did get his meaning by " and, bingo ."

[nola0000]

No, actually I didnt. Im thick like that. One of those people you have to explain jokes to. Please elaborate.

[99yam40]

[QUOTE=nola0000;78699
Still dont understand the discrepancy between the readings Im getting on a brand new part not being in sync with the service manual specs. Should I check for that 5V ref between one of the black/yellow wires and ground on the IAT?[/QUOTE]

It was his answer to this question of yours

Which means yes that is what you should do