One motor not spinning as fast after replacing both Kiss ESC and Kiss FC V2

[userix]

I have a quad running 1750kv stout ethix motors with Kiss V2 FC and Kiss 4-in-1 25A ESC with impulse RC regulator board and TBS crossfire.

I had an unfortunate crash into a swimming pool.

After replacing a new Kiss FC V2, all four new 1750kv stout motors, Kiss 4-in-1 ESC, and new impulse rc regulator board, I notice when I arm the quad, the rear left motor spins slower than the rest of them. The beeper through the motor also doesn't beep from the rear left (I can feel the vibration and see the vibration of the other three motors when motor beeper is on).

Without any props on and I arm the quad and throttle up, all other three motors would ramp up by itself as expected, but the rear left just stays spinning the same slower rpm and doesn't ramp up at all. I have activated and flashed both kiss FC and ESC using the same firmware I had previously and restored the same settings I ran before and also calibrated the accelerometer on the FC as well. I have also swapped the rear left motor with another working corner and rear left still spins slower, it doesn't ramp up while others do.

Since a working motor from a good corner is having the same problem in the rear left position, this made me think I had a faulty ESC and proceeded to replace it with another brand new one, but I am having the same problem again with the rear left spinning lower and not ramping up. When I try to take off with props on, the rear left would seem like it's underpowered and just won't spin up to speed. The quad would tilt down to the rear left as soon as I lift off the ground as all other props are spinning just fine except the rear left. I am using brand new lipo packs and I double-checked all soldering connections. It's puzzling why I still have this problem after replacing with brand new FC and ESC.

 

[CappyAmeric]

Because you get the same results with a different motor in #3 position, it sounds as if it might have either a mounting issue with the FC (forward and up orientation), or the ESC is bad. Even new ones can be bad, and of course too much heat for too long when soldering motors to the ESC pad can damage mosfets.

Try this: in BetaFlight, go to the Receiver tab with a battery connected and props off. When you move the transmitter sticks, does the animation of the quad in BF, move as expected?

 

[Bricks]

Did you recalibrate the ESC`s after the rebuild?

 

[LitterBug]

What ESC protocol are you running. If you aren't running D-SHOT, make sure you have recalibrated the ESC endpoints. If you are in the configurator, with the props off, and test the motors from the configurator, does that corner start and stop at the same % as the others? If you are arming the quad to spin the props, and the FC doesn't think it is level, it could be trying to level the quad by not spinning that motor as fast....

 

[userix]

What ESC protocol are you running. If you aren't running D-SHOT, make sure you have recalibrated the ESC endpoints. If you are in the configurator, with the props off, and test the motors from the configurator, does that corner start and stop at the same % as the others? If you are arming the quad to spin the props, and the FC doesn't think it is level, it could be trying to level the quad by not spinning that motor as fast....

Did you recalibrate the ESC`s after the rebuild?

I’m running dshot protocol. So I don’t need to calibrate it? I have calibrated the fc on a level surface a few times already. What also makes me think it isn’t a accelerometer level issue is the motor beeping not working on motor #3. I can visually see and feel all other motors beeping, but not on #3. I assume motor beeper feature should beep all motors evenly?

Because you get the same results with a different motor in #3 position, it sounds as if it might have either a mounting issue with the FC (forward and up orientation), or the ESC is bad. Even new ones can be bad, and of course too much heat for too long when soldering motors to the ESC pad can damage mosfets.

Try this: in BetaFlight, go to the Receiver tab with a battery connected and props off. When you move the transmitter sticks, does the animation of the quad in BF, move as expected?

I’m running kiss fc, I think I can check the same thing in the kiss GUI?

In terms of soldering motor wires, I was really quick. Didn’t heat the motor pads too long. This is my second brand new kiss esc, to get two bad ESCs in motor #3 position?

Fc orientation is exactly how I had it before and the settings are exactly the same. I made a backup before of the first working build and restored it once I got both the fc and esc on the same firmware I ran before