Fuel Line Hose/Primer?

[TownsendsFJR1300]

I would re-test the compression WOT for an accurate result.

As long as the compression is within 10% across the board your fine (you are with those #'s).

As for the plugs, that one is a quite a but cleaner than the rest but you should really check the plugs after getting some run time on them. At idle, a 2 stroke, with the oil injection , is going to not be as clean as a four stroke..

I'm not familiar at all with the O2 sensors but common sense to me, I'd take a steel bush and gently clean up the sensor of carbon, etc, maybe some brake cleaner where the actual sensor would be (I'd think inside that corrogated part).

And I have no idea what that black cylinder looking thing it what so ever...I'm not familiar with the other tests your doing (and even actually why)...

I'm certainly NO expert on outboards, I'll work on anything with a spark plug but I think you've covered most if not all bases and then some..

IMO, clean those couple of things, check the compression again, make sure there's no alarm ]s going off.

If it was my boat/engine, listening to the video, it'd be on the water. Just running it with a load on it at some higher RPM's will blow excess carbon, oil, crap out and should run better yet.


Again, pay attention to all your alarms...

[nola0000]

Weird...

Just checked a brand new air intake temperature sensor against my old supposedly bad one and the readings were only different by about 0.4V. Is there a mistake in the manual for the spec on the air intake temp sensor? Yamaha says 3.4-5.3 @68F. Im getting 2.2V(old) and 2.6V(new) @ ~55F and hotter air makes the voltage go down. Any ideas?

I was planning on maybe retesting the compression @ WOT so I could compare my readings against others on the forum.

Im not getting alarms and yes the alarm works.

I tried kicking it up to 3K rpms and it wouldnt hold it. Would jump up and down between 2200-3000. I did do the Seafoam thing so maybe its still kicking it out. Dont know.

Would unplugging the O2 sensor and listen for a change let me know if its working right?

[TownsendsFJR1300]

The RPM's shouldn't hop around that much but "freewheeling" it that fast without a load isn't the best thing for it..

As for the sensors, I don't have a clue..

Don't think it would hurt anything to try.

I do know to re-set the ECU on most (if not all) Yamaha motorcycle's, you just disconnect the battery for a couple of minutes.

[rodbolt17]

the O2 sensor resistance test is about as worthless as the flame test.
O2 sensor output MUST be checked with the gearcase submerged.
there are 3 tech bullitens out on how to test.
wanna bet any money your other"failed" parts are actually good??
you will find electrical problems are rare on yamaha.
but its your money.
intake air temp is a negative coeficient thermistor.
as temp increases resistance falls,same as the engine temp sensor.
spinning it up without a load,good thing I am not drinking and keyboarding, well its just .

[nola0000]

Thanks rodbolt. Can you point me in the right direction for these tech bulletins? Keyword search "tech bulletins", "yamaha" and "o2 sensor" doesnt bring anything up.

I havent spent any money on the failed parts yet. I tried soaking the O2 sensor in acetone per manual. I bought, tested and then returned the intake air temp sensor. What do you make of the resistance not being in spec?

What do you mean by "spinning it up without a load"? I know you mean revving the engine out of water but what about it?

[rodbolt17]

its a teat on a boar hog at best.
otherwise known as worthless and closing in on idiotic.
dont know if any bullitens are online but your local yamaha dealer can supply you with a copy.
when you tested the voltage out on the AP sensor,did you first verify your 5V reference?
same as the v output of the IAT and CTS sensors.
its a 5V two wire signal on the last two and a thre wire pick off voltage on the AP sensor.
the output specs are based on 5v ref.
if 5v ref is high or low the sensor output will change accordingly.

[nola0000]

Forgive my ignorance, I have a terrible time deciphering even the simplest of acronyms. Humor me, what is an "AP sensor"? Atmospheric pressure sensor maybe?

Where do I test my baseline 5V? Your instructions werent clear.

What does it mean of I dont get 5V? On the atmospheric pressure sensor I got 4.04V. Is this bad? Can it be adjusted? Is this the 5V reference you, umm... referenced?

[nola0000]

Just checked what I think is my 5V ref. between the red and orange wires on the throttle position sensor harness. I got 5.05V.

So whats next?

[rodbolt17]

TPS ref is good.
APS,bad.
garbage in garbage out.
find the poor connection.
any orange wire on the engine is a 5V+or-.02V circuit,black is ref ground and pink is the pickoff V back to the ECU.
low ref equals low pickoff.
dont confuse the pink sensor wires,engine,with the pink alarm wires,10 pin main.
remember temp switch is a SWITCH not a sensor.
coolent temp and intake air temp are 5V circuits,-coefiencient thermistors that return a voltage to the ECU.
means you should see 5v on one side and return V on the other.
google ohms law if you want to see what V you should see based on specified vs actual ohms readings.
either that 5V ref is bad out of the ECU or you have a bad connection or a load on the orange wire.

[nola0000]

My service manual says the APS output voltage (pink to black wire) should be between 3.2-4.6V. I got 4.04V.

Manual says for the IAT sensor you go between the two wires on that sensor which are both black with yellow stripe and you should see 3.4-5.3V @ 68F. I got around 2.4-2.6V with my old one and a new one @ around 56F.

[rodbolt17]

ill try again.
all the TPS and APS are is a 3 wire sensor.
5v is on the orange wire,a resistor with a wiper arm is in the device, the black wire is a ground.
its a potentiometer.
the resistance between the orange and black is high enough to drop all 5 volts.
thats why you see 5V from orange to black(ground).
now the wiper,pink wire, as we move that wiper away from the orange wire end of the resistor and towards the black we start another current path.
now I am dropping a certain amount of voltage between orange and pink.
remember eventually pink goes to ground in the ECU.
the ECU assumes that the 5v reference it generated for the orange wire is correct.
however if it was say 4 volts then any picked off voltage would be lower.

google kirtchoffs laws of voltage and current.

the ECU has no idea that the ref v is low.
however it can and will react to low pickoff voltage.

Voltage is a simple measure of electrical pressure between point a and point b
.
it does NOT flow NOR take the path of least resistance.

current flows and is measuered in amps.

its a measure of electron flow past a point.
no flow(break in the circuit) and the device wont work.

on your coolent and air temp sensors.
its simply a resistor that changes resistance with temp.

we place a 10K resistor in a wire between 5vref and ground.
remember there are components inside the ECU in its ground path.

now say we see 2.5V
now make the resistance double and we are back to 5.
now cut it in half and we are close to 0.
(numbers in the above are wrong,just for demo, to lazy to do the math).

think of that resistor as a throttling valve in a water pipe.

as you close it you build pressure(voltage) between the up and down stream sides of the valve AND you reduce flow(current) in said pipe.

now as you open said throttling valve,pressure(voltage) between point A,valve inlet, and point B,valve outlet,starts to equalize.
however or flow(current) increased dramatically.

simple 5V DC digital circuitry.

5V and 400mv twisted pair are industry standard digital signals.

[nola0000]

Rodbolt17...believe me when I say that I appreciate your time, your knowledge is highly respected in the world of Yamaha outboards but I dont think your last post had anything to do with my question.

My 5V reference was fine = 5.05V
All my sensors were within specification according to my Yamaha service manual except 3...

1. My O2 sensor resistance was off by a lot. Should be 100ohms. I got 4.5.

2. My high pressure fuel pump resistors resistance was possibly off but it kept jumping around so it was hard to tell. Should be between 0.53-0.57ohms. I got 0.5-1.1ohms

3. My intake air temperature sensor was reading low and the new IAT I tested read pretty much the same. Should be 3.4-5.3V @ 68. I got 2.4V @ 56F and 2.6V on the new one at the same temp.

Im wondering...

1. If I measured the O2 sensor right and if the ohm test on the O2 sensor is worth a damn since you dont think highly of the other Yamaha O2 sensor test...the flame test.

2. If the measurement I got on the fuel pump resistor is accurate but my multimeter cant read/hold a resistance that low.

3. Why the intake air temperature sensor reading was the same on the new one as the old since they are both wrong according to the Yamaha service manual.

Hope I didnt ruffle your feathers. Can you volunteer your input on these specific points?

[99yam40]

Did you ever think to try a different meter and/or meter leads.
If it cannot hold a reading or get the proper reading then there is a problem with the meter, the leads, or what ever you are testing.

Maybe the 5v reference to the IAT is low and that is why your readings are low.
Bad connections reducing the voltage or something dragging it down

[rodbolt17]

dont know about the 2.6L ECU but the 3.1L ecu has two 5v ref lines.
you can lose one and only lose a portion of the sensors.

point 1, that O2 sesnors ohms test only tests the O2 sensor heater circuit inside the sensor.
you also need 12V to it to make it work.
easy to test,plug in the sensor,turn on the key and wait a few minutes and see if its getting hot.
the KEY is O2 sensor running in the water OUTPUT voltage test.

point 2, quit chasing ghosts. all that resistor does is reduce pump operating voltage below 1200 RPM. this keeps the pump from running in a near stalled condion during periods of low fuel volume requirements.
above 1200 and you can toss the resistor in the creek.
monitor rail pressure is better than chasing 1/2 an ohm.

point 3,you still aint getting it. its a variable resistor.
varies with air temp.
IF the 5v reference is good thgen the voltage drop ACROSS said resistor will be minimal when its cold and a lot when its warm.
low 5 v in results in low output. same with a bad harness connection.

2nd #1,refer to my first #1 answer.

2nd #2,refer to above #@.

2nd #3, it varies with air temp, dont belive it soak it in ice water,take a reading,now while still reading hit it with a hair dryer at 1500 watts.
however if my 5V refence is low then my voltage drop acrossed the resistor will be low.

do you live at or near sea level?

this ECU is rather stupid,if a voltage fed back to it is within its mapped range it reacts.

an example, the engine coolent sensor or wiring suffers a partial failure and the feed back voltage is telling the ECU your duck hunting(25*F).
however your in the fl keys and its 98 degrees outside.
what do you think the ECU is going to do with the injector time on(pulse width)?
how would the motor react?
same as the intake air temp,
how would the engine react?
25*F is well within its mapped operating temp range.

[nola0000]

rodbolt17...

1. Interesting info on the O2 sensor. Ref V is good and output V at the O2 is within spec but the ohm test is out of spec. I guess the heater circuit in the O2 sensor is bad. Should I check resistance with the engine running? The service manual didnt specify a test procedure for the resistance, just for the output voltage.

2. Great stuff! Ill ignore the fuel pump resistor. One less thing Ill have to worry about.

3. Sorry if this sounds rude, but I posted in this very thread the exact thing you just said. That is why Im so curious as to why both a new and old part would be out of spec if my 5V ref is good. I thought that the spec in the manual might be a misprint or the new part I got might have been bad. The package was opened.

"Just checked a brand new air intake temperature sensor against my old supposedly bad one and the readings were only different by about 0.4V. Is there a mistake in the manual for the spec on the air intake temp sensor? Yamaha says 3.4-5.3 @68F. Im getting 2.2V(old) and 2.6V(new) @ ~55F and hotter air makes the voltage go down. Any ideas?" AND "*FAILED* Inspect intake air temperature sensor = 2.4V @ 56F (spec 3.4-5.3V @ 68) - subjected to ice cube = voltage down, subjected to hair dryer = voltage up to 3.0V in after ~5min)"

Temp outside today was 69F. I checked the IAT sensor again since thats pretty much the 68F that Yamaha calls for the test to be taken at and I got 2.55V.