HELP ! 02 F225 ECU Log hours show "0" engine missing backfiring

[rodbolt17]

obviously something went wrong.
most likely the ISC overheated the ECU or an electrical spike.
not saying the ECU is or is not bad.
I have seen the ECU overtemp due to the ISC and actually melt all 3 coils and the coil holder.

so my bet would be on careful testing and observation before busting out a boat unit.

[magnoman]

Thank you RB,
Will do as your suggestions .
I did notice ign timing was all over s . Also will pull Thermostats and test them and look @ISC

[magnoman]

Update ,
Had motor running for about 5 min still spitting and sputtering idle rpm all over ECU hours know read "1" guess it counting back up . Had YDS attached was monitoring ISC seems to be working turned off motor and ISC valve was so hot could hardly touch it ? is that normal ? removed the ISC valve seemed clean plunger was free . Installed ISC started motor ran for about 10 min at idle Timing reading was again 2-4-5 dg then nothing (not even a number ) then would read again . Motor temp @ 123 , so not running hot .
So assuming here that ISC is overheating or had over heated and fried ECU ?

[fairdeal]

Once again, the % values that you see in YDS for the ISC are "requests" from the ECU - there is no "sensor" that show what the ISC is actually doing.

in the Stationary Test section of YDS is the "Operate ISC Valve" function which is useful to activate the mechanism and watch to see if it responds, as in this video:

https://vid.me/83AD

[boscoe99]

Seems that Yamaha should have used a "driver" between the ECU and the ISC valve to avoid excessive current flow through the ECU, thereby damaging it.

Yamaha likes to use extra parts. I wonder why they did not in this case.

[TownsendsFJR1300]

Had YDS attached was monitoring ISC seems to be working turned off motor and ISC valve was so hot could hardly touch it ? is that normal ?
So assuming here that ISC is overheating or had over heated and fried ECU ?

The idle control valve should not reach temps that hot.

It's been posted here, above 200 degree's F (or so) and it's likely toast..

[magnoman]

Yes it did get very not not sure if over 200F . I should have used my laser temperature gun and checked .
Will get temp reading tomorrow ..

[fairdeal]

its quite possible that I fall into the "wuss" category -

but "painful to touch" for me, starts as low as ~120 F

[TownsendsFJR1300]

Post #21 to get an idea of the temp (100-140F) and the re-building of an ISC as the bearings internally tend to seize:

http://www.yamahaoutboardparts.com/f...h26563-p2.html

http://www.yamahaoutboardparts.com/f...t-th26922.html

.

[magnoman]

Guess I am getting the temp gun out ...

[TownsendsFJR1300]

When you turn the engine off, you should hear some clicking (3-5 seconds or so) coming from the unit.

That's the unit re-setting itself (if operating properly) for "another start up"

[magnoman]

Yes hear the clicking sounds .. don't know something made my ECU die ...

[magnoman]

Update,
I installed used ECU started up and ran with out ISC valve plugged in just in case it was bad and frying ECU .. It idles good
new ECU read 987hrs 500 at idle .
all YDS monitoring showed no out of spec sensors . Timing 4-5dg , injectors read 2.34 -3..
after letting idle for a bit checked ECU hrs they have been set back to Zero once again !!!

Motor know idles pretty good no missing or popping but when rev up still missing and popping and seems to bog down like timing is not advancing ..

At this point have given up and hired expert Yamaha mechanic who has been working on these motors since they came out to do a road service call .
Will see the out come some time next week ..

[fairdeal]

Update,
I installed used ECU
started up and ran with out ISC valve plugged in just in case it was bad and frying ECU

new ECU read 987hrs

after letting idle for a bit checked ECU hrs they have been set back to Zero once again !!!

this continues to be most interesting

[ed janke]

hi all . just had 1 of my f-150 gage also erase hours ,came back on few minutes later starting over at 0 , any updates on the problem