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

[magnoman]

Hi guys ,
Had warning buzzer go off at idle after running for 10 minutes shut her down restarted engine low rough idle hardly runing when try to rev engine missing sound like internal backfiring ? Did scan with Yamaha diagnostic software showing no codes all engine monitor seem in spec but noticed the run data log of hours is showing "0" I know and had seen before engine has about 1k hours on it .
Thinking something went wrong with ECU ?

[pstephens46]

Alarm buzzer usually triggered by overheat or low oil pressure. Don't see the water in fuel sensor attachment for your motor, so we can rule that out. You didn't see a visual indicator on your tach either for heat or low oil pressure?
Others will add comments, there has been comments in the past that low voltage can create strange problems also.

[magnoman]

No warning light in tach or low oil pressure warnings. and yes entire mid section baffles and exhaust was replaced few years ago .
Running yamaha computer diagnostic software scan all engine monitors are showing in spec and no codes . BUT what is strange the engine log hours showing "0" ECU not logging hours and has lost the memory . I suspect the ECU failed .
Also went to Yamaha local dealer and spoke to service Dept they also think ECU went bad .

[pstephens46]

Could be. Hope not. I have read that ecu failure is rare. Maybe Rodbolt can confirm?

[fairdeal]

I believe Rodbolt has written that, in his career with Yamaha outboard service, the number of ECUs he has replaced would fit in a paper lunch bag.
So not common.
But he has also specifically pointed to a defective ISC valve as being able to overheat and "destroy" an ECU.

[magnoman]

Don't know but had Alarm go off while *****ing shut motor off right away no lights on let it sit for a bit started right up came in about 15 min run at 4k rpm ran great threw comp on showed no fault codes ? Few days later was idling at dock for about 10 min alarm went off once more then ever since then she hardly runs and ECU showing no log hours and ISC valve in spec ..

[fairdeal]

and ECU showing no log hours and ISC valve in spec ..

I'm not saying your ISC is the problem here - but what do you mean, its "in spec" ?

the only thing YDS can tell you about it, is what % opening the ECU is requesting it to be at.

Where it actually is - or what its actually doing - the system doesn't know. There is no "feedback".

Now, the ECU wiped of hours - that's amazing.

[magnoman]

Yes ECU wiped of hours reads "0" that makes me suspect something in ECU is fried ...
When running the YDS as I have seen before when things are out of spec such as the TPS it show in red . I can get correct values from manual and reference them to what YDS is reading I guess .

[99yam40]

I have read about ECUs showing the wrong hours before, but never back to zero.
would be nice to have a spare to try, but buying one to just see does not sound like the proper thing to do

Posting a screen shot of the readout while missing might get some info from Rodbolt

[magnoman]

Well just purchased a used ECU on ebay for $330 will try that if not well put it right back on ebay . Will try to get screen shot .Did noticed timing all over the place - 2 degrees to 4 to reading nothing just blank readout .
Some ghosts in the machine thats for sure

[pstephens46]

Where is Rodbolt?

[rodbolt17]

reading.
wondering why so much splatter gun trouble shooting occurs.

[pstephens46]

Don't leave us hanging!

[rodbolt17]

YDS is a good tool.
the tool twixt the ears is better.
YDS cannot and will not trouble shoot anything.

it will only display what the ECU inputs and outputs are.

if something goes out of range it usually will display a code for a fault.

that simply means that device input is inccorect not that the device is bad.

first thing you do is observe the screen at key on engine off.
does it display what you would expect for all sensors/switchs?

at engine running does the display match what you would expect?

if the injector on time is moving about or very long it is trying to compensate for something.
same as ign timing.

[TownsendsFJR1300]

If voting, I'm in for a bad ECU!

(especially with the hour meter re-set)


Possibly burnt out from an overheated ISC..