2004 Yamaha F90TLRC will not shut off

[NWwalleye]

Ok.. Chased the wiring harness ..
No faulty wires, no faulty connection.
White wire continuity good .. Black ground wire continuity good ..

Put back in the water .. Did the simple stupid test again..
Turned key to "Off".. No shut down..

Grounded white wire paper clip to a known ground..

Guess what ... no shut off ....

So I tapped the ECU/CDI/TCI with my screw driver lightly.
Engine shut off ..

Restarted engine, turned key and engine shut off again..
Revved up motor, turned key off and no shut down..
Tapped ECU/CDI/TCI and engine shut off..

Did this several more times ..

Now, engine starts and shuts off every time..

What now ...

[TownsendsFJR1300]

I would check the connectors in the TCI/ECU harness (at the TCI/ECU) to make sure none of the pins got pushed out and have a crappy / intermediate contact (as you seemed to have narowed it down to that area). Should be nice and clean, no corrosion obviously..

That could very well be your bad connection you've been hunting..

[99yam40]

could be a cold/bad solder joint in electronics or a crack on circuit board.

Strange tapping on ecu makes connection

If you check all connections ,
and run a separate wire ,
and still have the problem,
you might see if you can find another Ecu to try before buying one

[NWwalleye]

I would check the connectors in the TCI/ECU harness (at the TCI/ECU) to make sure none of the pins got pushed out and have a crappy / intermediate contact (as you seemed to have narowed it down to that area). Should be nice and clean, no corrosion obviously..

That could very well be your bad connection you've been hunting..

Thanks..
I will double check...
They looked fine the first time I looked ..

[NWwalleye]

could be a cold/bad solder joint in electronics or a crack on circuit board.

Strange tapping on ecu makes connection

If you check all connections ,
and run a separate wire ,
and still have the problem,
you might see if you can find another Ecu to try before buying one

Thanks for the info ..

[rodbolt17]

boscoe
I can agree with some points.
some master techs I have run acrossed probably should not be but its a tough test to pass and it does require taking all six courses.
some techs are in it cause its a job and WONT self teach.

you think someone held my hand and explained all this to me?

the way my pay works if I come in and say joe scmoe needs an ECM and the shop buys it and it does not work. I buy the ECM.

I don't own any spare ECM,s or Ign coils or TPS units.

doesn't hurt that I spent 10 years or so in the automotive field, 6 years setting up and programming CNC lathes and mills and 6 yrs or so in the USN in the advanced electronics program.

got my first Chiltons manual at age 8 and I am 52 now.

[rodbolt17]

if you have the white wire grounded at the ECM and it doesn't shut off that only leaves the ecm.
especially if tapping on the ecu produces the correct results.

its the most common ECU failure I have seen on the F115.
all 3 or 4 of them.

[TownsendsFJR1300]

boscoe
I can agree with some points.
some master techs I have run acrossed probably should not be but its a tough test to pass and it does require taking all six courses.
some techs are in it cause its a job and WONT self teach.

you think someone held my hand and explained all this to me?

the way my pay works if I come in and say joe scmoe needs an ECM and the shop buys it and it does not work. I buy the ECM.

I don't own any spare ECM,s or Ign coils or TPS units.

doesn't hurt that I spent 10 years or so in the automotive field, 6 years setting up and programming CNC lathes and mills and 6 yrs or so in the USN in the advanced electronics program.

got my first Chiltons manual at age 8 and I am 52 now.

Not to de-rail the thread, but agreed with Boscoe 100%.

I've dealt with several different Yamaha shops and have literally had them replace(under warranty) the entire THROTTLE BODY assembly($1,000) due to the known low idle issue, (F150) stall when docking. It didn't cost me a nickle but I know it wasn't needed. Many other issues as well due to incompetance. I have found a Master Tech at a certain marina, if needed, I'll make an appointment and run the boat 25 miles to get there... I don't mind paying for experiance what so ever and a repair done correctly.


Rodbolt, most here are very aware of your decades of experiance, I myself am often wrong but also enjoy learning from you and others. I do get things right on occassion W/O a shop manual, never seeing or touching that engine, maybe a parts fisch and general mechanical knowldege.

*Point being, things that are VERY basic to you, simple stuff, known for years, are NOT KNOWN by others as they haven't been to the specialty schools. Its NOT all "common sense" in different issues, especiallly something specific to a specific model (ignition style unit, etc). I've read your posts literally decades ago (same user name) just last night on another forum..

Please keep in mind, most likely, EVERYONE posting here DOES NOT have your schooling, and most, not full time mechanics of any sort.

Disrespectful, demeaning answers, by anyone, is certainly NOT helpfull.

Anyway, back to the thread...

[boscoe99]

Great points Scott.

One of the hardest things in the world is to know something and fail to recognize that what is so readily apparent to ones self may be difficult for others to understand. Simply because they just have not yet learned it. Not because they are stupid or anything.

There is much more that any of us does not know that we do know or can ever know. New stuff is being developed faster than I can keep up.

There are those that can do, but can't teach. There are those that can't do, but can teach. Best of all are those that can do, can teach, and have the patience to teach. It helps to think back to the days when I was learning something and I had a patient and kind teacher. He did not give up on or ridicule me. We don't soon forget those teachers in the past that contributed to us being where we are today.

[NWwalleye]

if you have the white wire grounded at the ECM and it doesn't shut off that only leaves the ecm.
especially if tapping on the ecu produces the correct results.

its the most common ECU failure I have seen on the F115.
all 3 or 4 of them.

Thank you for the conformation and your patience..

All your advice and information helped me out greatly..

I guess I will have to buy a new ecu/cdi/tci ...

Is this the correct part number ... 67F-85540-02-00

[almetelo]

as a backyardigan I thank you for share your wisdom and I do admire your humility and patience to understand the other side... of people like me that like to learn but have low wisdow on this. THANKS guys!
But as ROD posted once the goodwill and interest sometimes is far from be enough to solve some stuff.

Thanks ALL

[TownsendsFJR1300]

Thank you for the conformation and your patience..

All your advice and information helped me out greatly..

I guess I will have to buy a new ecu/cdi/tci ...

Is this the correct part number ... 67F-85540-02-00

Didn't find any loose wires at the harness / back of the ECU I gather?

[NWwalleye]

Didn't find any loose wires at the harness / back of the ECU I gather?

Nope ...
Took harness apart and all is good.
Checked all plugs and pins .. Cleaned with contact cleaner .. All good..

Wires / Back of ECU ??? Don't follow ..
Just 3 plugs on ECU .. Pulled each inspected cleaned and re-plugged ..

[boscoe99]

I suspect that he was suggesting that the socket for the white wire in the harness be inspected for good condition. There should be a device on each connector that will release the sockets. You can pull out the white wire and socket, clean it individually, make sure that it tight and will make a good connection to the ECU pins, and then reinsert it. If you want one final check before spending the bucks for an new ECU.

[TownsendsFJR1300]

I suspect that he was suggesting that the socket for the white wire in the harness be inspected for good condition. There should be a device on each connector that will release the sockets. You can pull out the white wire and socket, clean it individually, make sure that it tight and will make a good connection to the ECU pins, and then reinsert it. If you want one final check before spending the bucks for an new ECU.

Exactly!^^^^

I have no idea what your ECU looks like nor the connector(s). I do know connectors like to be nice and clean with no corrosion..

Especially since, per Rodbolt, they rarely go out. Your just unfortunate to be one of the few...

Please post your final results..