ox66 high idle

[ttles714]

So my starboard SX250 (2001) OX66 idles at about 1100 RPM.. Port at 7-800 .. Not sure where to start or what the most likely suspect is .. The service manual lists about 8 or 9 different sensors but does not list how to check them . Does anyone have a Likely Suspect ?? Maybe most common place to start . Other wise both motors run very well.

[rodbolt17]

the service manual is very explicit on how to test each sensor.
all it takes is a multimeter and some paper clips and jumper leads.
or the meter and the correct test harness.

a quick check with the diagnostic test lamp will work as well.

can top speed be reached?
if it can that eliminates a pulser coil,a TPS a CPS baro sensor and a few others.

if the ECU "sees" any sensor failure or out of range feedback it locks ign base timing at 7*BTDC,and it now idles about 1100 RPM.

depending on WHAT failed timing may or may not advance and top speed may OR may not be reached.

that motor will mostly troubleshoot itself with some simple tools and an understanding of what each sensor/switch does and why it is there.

DO NOT even hunt the O2 sensor.
it is not monitored for faults.
if disconnected fuel is fixed rich at low speed and lean above 4000 RPM.

[ttles714]

thanks

top speed is fine .. no change there ... is there an order you would start checking ?? From your experience ?? I have a Winky Blinky that i have never used ... will that help in the diagnostics ??? thanks for your help

[boscoe99]

the service manual is very explicit on how to test each sensor.
all it takes is a multimeter and some paper clips and jumper leads.
or the meter and the correct test harness.

a quick check with the diagnostic test lamp will work as well.

can top speed be reached?
if it can that eliminates a pulser coil,a TPS a CPS baro sensor and a few others.

if the ECU "sees" any sensor failure or out of range feedback it locks ign base timing at 7*BTDC,and it now idles about 1100 RPM.

depending on WHAT failed timing may or may not advance and top speed may OR may not be reached.

that motor will mostly troubleshoot itself with some simple tools and an understanding of what each sensor/switch does and why it is there.

DO NOT even hunt the O2 sensor.
it is not monitored for faults.
if disconnected fuel is fixed rich at low speed and lean above 4000 RPM.

Don't you mean CPC?

If you are talking about the crank postion thingamajiggy.

[rodbolt17]

they call it a CPS, Crank Positin Sensor.
the CTS is a Coolent Temperature Sensor.

hook up the winky blinky, start the motor with the gearcase submerged in the water.

see what blinks.
it should start out blinking a code 33.
this will be 3 blinks a pause and another 3 then a long pause then it repeats.

if all is normal when the CTS reachs about 113*F it will shift to a code 1.

if it is abnormal it will blink the lowest code first and only.
you must repair whatever is tossing the lowest number code to find if there is another code.

[rodbolt17]

A side note on the diagnostic test lamp.
it plugs into the engine side of the engine oil tank harness.
the blue lead plugs into the blue unused lead at the engine oil tank.

NOTE: NO automatic oil transfer will occur when using the test lamp.
all alarm functions and manual transfer will work.

[ttles714]

resolved

I found no connection at the Green wire which i believe goes to the knocking sensor, located in about the middle of the starboard cylinder head .. Does that seem right ??? Idle is back to normal ... its nice when its the simple things .. i have to remember to check the simple ones FIRST !! Thank you all for your help .. ...Again thank you ALL

[rodbolt17]

a disconnected Knock sensor will make it idle at about 1100 RPM,timing base fixed at 7*BTDC and top speed can be reached.

the ECU was trying to tell ya something is wrong.
kinda like a check engine lamp.

[rodbolt17]

ifinn ya don't belive me.
simply start the engine.
allow it to warm up.
unplug ANY sensor you wish.
watch what the RPM and IGN timing does.

wont hurt anything and you may learn something.

[cpostis]

Just in case you need instructions on how to connect the "Winky Blinky", here is a thread answered by Rodbolt from another forum, years ago.



"Using Yamaha diagnostic indicator (winky Blinky)
April 14th, 2010, 01:19 AM
What is the proper way of using this tool on a VX225TLRY (225 Vmax)? The part number I have is 13-YB-06795. I tried it last weekend and followed the service manual, however the manual does not say what to do with the other connection on the tester. The engine ran like it was on half the cylinders and the test bulb did not flash at all. I ran the test after the engine had been runing for at least 30 minutes. I did not run the test for more than a few minutes because the engine ran poorly with the diagnostic indicator connected. Any instructions out there on how to use this thing?

rodbolt
Supreme Mariner

Join Date: Sep 2003
Posts: 20066
#2
April 15th, 2010, 05:36 PM

Re: Using Yamaha diagnostic indicator (winky Blinky)

with engine off unclip the oil tank wiring at the engine oil tank, attach the lamp to the engine side of the oil tank harness.
now go find the single blue wire with a female bullet connector and a rubber cap just fwd of the engine oil tank.
remove the rubber cap and connect the lamps blue male connector to the female and retry."

[ttles714]

I'm a believer

Thank you again .... just as you described how the motor would behave is what it did ... .. the instructions with the winky blinky are a little vague but maybe its just a matter of using it ... like anything else !! I bought the tool probably 5 years ago ( when i purchased this used boat ) thinking with these older engines i would be having some issues... but they have been reliable to say the least... i never opened the packaging !! ... the only issue i had was a relay and LP fuel pumps . Most of the aggravation involving fuel pumps was due to aftermarket pumps .... So thanks again to All