Struggling to figure out the cause of misfires

Hi everyone.

My 2008 R3T is driving me nuts. She works perfectly on idle, but misfires start as soon as I open the throttle. Doesn't matter how wide the throttle is open, engine keeps stuttering, backfiring and all that.
The setup is Ramair/TOR/Nels tune.
I've thrown in new spark plugs, new ignition coils. Air filter is clean. Tried different gas stations. Nothing helps.

TPS sensor seems to be fine. TuneECU shows throttle position steadily in all of the range.

Could this trouble be caused by faulty ignition wires? I'm ready to replace those too. Would hate if this wouldn't help either.

Also, I've noticed that the primary stepper motor is behaving erratically. When testing it with TuneECU TPS voltage on closed shows 0.62V (which is within limits), yet during the second stage of testing (open) the voltage keeps jumping from 0.72-0.74 down to 0.6 and even below that. The motor itself is not humming steadily but keeps screeching. I don't believe this should be a normal behaviour.

However, as far as I understand, the stepper motor should be affecting only idling, and not open throttle modes. Correct me if I'm wrong.

Anyway. I'm banging my head against the wall here, so suggestions and thoughts would be appreciated.

Have you cleaned the crank sensor?

martym52 said:

Have you cleaned the crank sensor?

Click to expand...

Yep. The engine was recently rebuilt. Everything was fine after assembly.

How about the vacuum hoses. Are they damaged or not correctly installed?

Might want to consider the over the plug style upgraded coil packs vs the problematic 3 coils it comes with.

Aye, I'd crimp the plugs on coils again.

If that doesn't fix it my next check would be downloading the tune from the bike to a laptop. Check for corrupt tables, I've had corrupt uploads on both the R3 and my Daytona.

If that's not the problem, I'd be investigating primary TPS sensor and MAP sensor.

Claviger said:

Aye, I'd crimp the plugs on coils again.

If that doesn't fix it my next check would be downloading the tune from the bike to a laptop. Check for corrupt tables, I've had corrupt uploads on both the R3 and my Daytona.

If that's not the problem, I'd be investigating primary TPS sensor and MAP sensor.

Click to expand...

This....
I thought I had a misfire issue and I whent down the rabbit hole and it seems that it cant be more than a few things
One thing that's easy... check the spark plugs gap. It's not entirely impossible that there could be a defective one or a bad gap.
Supper easy to check too

Failed TPS.
Identical symptoms.
Pattern failure.