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Discussion Starter · #1 ·
It’s almost 3 months since I first posted with my 999 with intermittent failure on #1 only, and I write this to try and save those with limited experience with the 999 (like me) from the angst I have suffered. I would also like to say a sincere thankyou to those of you that have been very supportive of me during this time.

I initially determined that the issue was #1 injector was not delivering fuel (ie visual check), and the fault code indicated an injector fault. This included at one stage where the bike ran well until about 7800rpm (ie the fake rev limiter)

To resolve this I have: Swapped over injectors, Removed, replaced and removed the PC3, Cleaned all plugs and sockets, Checked injector coil resistance, and ecu plug to injector circuit continuity and continuity to earth (whilst moving, bending, twisting the various looms and plugs), Unwound the loom binding tape (what was left) and visually checked and flexed the individual cables, and checked the “in loom” cable joints.etc etc etc

I could only get the fault to occasionally appear when I twisted/flexed the engine ecu plug and cables. Connection of an oscilloscope to the cables showed signal loss at the engine ecu plug. Conclusion: either a faulty ecu or ecu plug, more likely the ecu. Do not pull the ecu apart to see if there are any dry joints. Error, wrong! This sent me down the path of fitting another ecu and the learning and activities associated with remapping and disabling the immobilizer (not) and "new" issues like code 34. Eventually, the bike started and ran like clockwork.

So, today I rebound all the wiring, fitted it all back together, grabbed my helmet, fired it up and it ran beautifully…..on one cylinder. FCK. Check the fault codes, again. Same code, 10.2, again. Injector earth fault.FCK

Stripped it out again, pulled the engine ecu plug apart, again (sort of) nothing obvious, put it back, again, runs on 2 cylinders, again. WTF. I was pissed and hit the battery cage while it was running on 2 cyl. 1cyl. So, holding, bending, twisting ect I tracked it down to a faulty coil plug....

There has been spark every time I pulled the plug to check, there were no codes to suggest that there was an ignition issue, and I didn’t know that the ecu must shut the injector down when it detects an ignition issue, even if doesn’t report.

Oh well, I've learnt a lot, even if I was walking down the wrong path.....
 

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Discussion Starter · #3 ·
When we as rookies trying to find an issue are supported to the extent that I was by the pros I believe we have a responsibility to post our final findings.....
Regards to all, Greg
 

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Hey,
Congrats on finding the fault. Intermittent faults are the most difficult to track down. Even for the pros. I worked in Heavy Equipment for over 2 decades. I've run into intermittent faults that took days or even weeks to find. Granted, there are a large number that were found in minutes but those are the more easily isolated ones.

Ignition and fueling are somewhat intertwined electronically so separating one from the other can be difficult. A fault like you were experiencing might have taken days to locate, even for a pro. Thanks for closing the loop and filling everyone in on your findings.......sean
 
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