Full throttle Power loss after 9000 rpm

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IIRC both the intake runners and exhaust valve are stepper motors. The bike would only know what position the motor is at or if the motor was disconnected. There’s no means to detect the position of either the runners or exhaust valve if the linkage is damaged or was incorrectly assembled. That’s the problem with relying solely on the lack of an engine code to exclude possible troubleshooting routes.
 
If there was a secondary injector issue, I would think an air/fuel sniffer in the exhaust during the dyno runs would give some indication of that. On the code thing, the bike doesn't know how much fuel is flowing from the injectors. It only knows the fuel pressure and flow along with injector opening time. If the injectors don't actually open, or do so in a less than optimal way, I don't think a code would be tripped.
 
Mcv4 said:
The repeated problems over both tune files and RPM range look almost like a possible secondary injector issue. You'd think it may bring up a code but still a possibility to throw out there.
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You could probably snake a camera tool into the airbox after removing the air filter and directly observe them operating along with the intake runners.
 
Yeah completely understand what you are saying. Thinking more along the lines of injector plugs possibly gone back onto the wrong injector at some time or injectors firing in the wrong sequence for some reason. I'd need to read back if the problem happened all of the sudden or after work performed.
 
Yeah, I'd love to read an accurate service/trouble/mod history of the bike. There's something clearly afoot, but there's not enough information to offer anything but a guess.

I'd love to see that same dyno run with wideband O2 sensors installed. At the same time though, something is cutting air or fuel at a very specific point. I'm not feeling it's a spark thing, but again, no data to really suggest it's not.

@HenrikE There was a TSB about the bolts which hold on the sparkplug resistor packs backing out. Are those all installed like they should be?
 
i had same issue.Fist step is back to stock tune, second step you need use fuel injector cleaner 3 tanks and ride about 1500 km to clean
 
bp_SFV4 said:
If there was a secondary injector issue, I would think an air/fuel sniffer in the exhaust during the dyno runs would give some indication of that. On the code thing, the bike doesn't know how much fuel is flowing from the injectors. It only knows the fuel pressure and flow along with injector opening time. If the injectors don't actually open, or do so in a less than optimal way, I don't think a code would be tripped.
Click to expand...

I asked and they didn't use AFR sensor claiming it can't just be dipped into the exhaust on the v4 without touching the cat.

Anyway... They now tested all the injectors and all but 1 was in spec. They cleaned/fixed it but did not resolve the issue.
Now that they stripped the bike they are convinced the bike has been in a crash😑.

Story continues
 
camposgabriel said:
i had same issue.Fist step is back to stock tune, second step you need use fuel injector cleaner 3 tanks and ride about 1500 km to clean
Click to expand...

Thanks for input! It is back to stock map. Injectors has been out for a clean but didn't resolve the issue.
 
HenrikE said:
They say the lower triple clamps and the bracket that holds the fairings and dash is not straight.
Click to expand...

Interesting. That would suggest a front impact.

Are there any cracks or damage to the air box?

Do they have the means to test that the velocity stacks are working and to sync the throttle bodies?
 
Is there a log from the lean over sensor or IMU that suggests it’s been in an accident? Not that it would influence what’s causing this. Sounds like Ducati or the dealer is now trying to weasel their way out of this mess. Something isn’t kosher here
 
Steven31371 said:
Didn’t read the whole thread but in case nobody mentioned it that kinda sounds like the clutch going bad?
Click to expand...

Don't think so, because then the revs would go up on the dyno.

It's been taken to pieces for valve checks and plugs change. Will go on the dyno again soon, then we'll see. Not having high hopes.
 
DCPanni said:
Did they test to see that the throttle grip when it’s rotated through its full range will output the correct voltage? It’s an electronic throttle, when you twist the grip a voltage level is generated and sent to the ECU as a throttle input. I suppose it’s possible that the throttle twist mechanism has gone bad, and won’t send out the right voltage to indicate a higher rpm level. They need to datalog this somehow. A good diagnostic tool should be able the read out what the throttle position sensor is outputting.
Click to expand...

At least on the newer bikes when the throttle signal starts to go bad it largely stops the quick shifter from working, because that relies on the throttle input being within parameters or it just disables it. Dunno if that’s true on a 2018 bike though.
 

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