2002 F225 High Idle 1,200 RPM

[gradytampa]

Any ideas what to replace next?

[fairdeal]

Any ideas what to replace next?

oh no - don't get Rodbolt started about standing back and throwing parts.

The ECU "tells the ICV to open and close"

but it doesn't know whether it actually has or not

Rodbolt has mentioned several cases where a bad sensor has caused a garbage in/garbage out situation for the ECU

did you mention checking the engine with the Yamaha Diagnostic software to see what the various input values are?
or measuring the sensor reference voltage?

[pstephens46]

Thermostats will not affect idle issues. Guessing that motor still thinks a faulty sensor is attached somewhere. More electrical testing is in order.

There is a chapter on testing the various components in the service manual.

[rodbolt17]

12V + is supplied to the ISC anytime the key is on. the ground paths to open or close the valve is done via the ECU.
it is NOT monitored for any faults but can me manually toggled with YDS.

BEFORE I replace any sensors I test the reference voltage and the output voltage first.

that ECU and YDS is a rather dumb thing.
the tech must know what to expect at key on engine off and then running.

there were two recalls on the throttle linkage that can also affect idle speed if they have not been done.
a yamaaha dealer can use your PID and find out.

I warned you not to take it to Joe Bubba .

that big snap-on tool box only means he can make a payment.
the best tool is the one between the ears.

[rodbolt17]

that is a switch not a sensor.
they tend to stick.
that little micro switch button gets gummy.
all it does is tell the ECU if it is in a gear or not.
you can also set it by revving the motor in N.
the reason for the high idle will be displayed on the YDS.
you may or may not see a code but the reason will be there.

goes back to the tool between the ears.

[gradytampa]

The mechanic said that the yds was reading zero oil pressure, he said he replaced the sensor and it showed normal pressure and no codes. My tach shows no codes or flashes whatsoever. He did say that the voltage readings on the isc were not what they should be. If it were throttle linkage, when I disconnect the isc shouldn't there be no change in idle? I was curious about not having an alarm sound, my guess was maybe the alarm was broken.

[gradytampa]

I'd like to think that a new aftermarket sensor would perform the same as a new oem , but possibly not last as long. Everything is the same, just inferior quality parts correct?

[fairdeal]

Check for basic function of the alarm by pulling the killswitch lanyard - then "start the engine" - the horn should sound as soon as you try to crank

He did say that the voltage readings on the isc were not what they should be.

And so his next step is - what?



Capt Solo has a somewhat rare tach which flashes engine codes -
most of us do not have that feature.

He makes a good suggestion to find a more knowledgeable tech

[rodbolt17]

there are no real voltage specs for the ISC and it is NOT monitored by the ECU.
there is 12v+ supplied by the main relay. the ground is toggled by the ECU to move the pintle in or out.
at least he now owns a spare ISC.
dealer search.
,master tech.

[gradytampa]

Capt solo, to answer your question it idles high with the original icv and the new aftermarket, only when I disconnect and restart does it go back to 600-700rpm . I did not try reinstalling the "faulty oem" icv and disconnecting. I am very skeptical that linkage has anything to do with it being that it runs fine when disconnected. I don't want to FUBAR the engine , so I called the nearest master tech 5 star dealer and am dropping off today. I'll let you all know what they find.

[gradytampa]

Just dropped the boat off and ran the tech through what's been gone no on. I was hoping he'd say " oh yeah I know exactly what's going on based on the symptom". That wasn't the case, he said he would takes look in the next couple of days and hopefully isn't something going on with the ecu. He said if it were in limp mode from a sensor, it would not being running at 100% throttle.

[99yam40]

the spark timing can and will increase the rpm if it is advanced instead of retarded at idle( not in spec)

[rodbolt17]

every one is nuts.
no one apparently can simply look at the lap top and do it.
and yes most times it is not the ECU OR yds.
IT is BETWEEN the ears.

[99yam40]

99yams writes: the spark timing can and will increase the rpm if it is advanced instead of retarded at idle( not in spec)

That's true. But when he disconnects his ISC the engine idles normally.

If the ISC controls the idle, and it idles right when it is disconnected, why is it necessary to have it hooked up at all?

When he hooks it up, it idles at 1100 RPMS.

as Rodbolt posted, looking at YDS will show what all is going on.
including the timing
what is the timing doing while the motor is idling high and then normal.
simply looking at what different things are doing will help that tool between the ears.

[rodbolt17]

at key on what does the ECU see?
what would you expect?
at idle what does the ecu see?
what would you expect?
that is where a tad of training and a touch of experience kicks in.
the ECU cannot trouble shoot.