motor not running smoothly

[John g]

Hi, can anybody possibly help me to diagnose a problem?

I am a complete novice in relation to E bikes.
I have an Evo pro jet 2018 model, that in all appearances looks like new. I believe it has a cadence sensor, called TMM 4 that should react to chain motion. But then again I an a complete novice. I have looked at the sensor and it is not dirty and looks fine (I do realise that there still could be something wrong, but there is no dirt in play.

There are four "speeds" Eco, Normal, Sport and Boost
The problem seem to be that when peddling, especially in the three lower speeds the motor appears to cut out. The action of the pedals to power is not smooth but putting more pressure on the pedals the motor kicks in again and then sets out. Kind of like bursts of power that last for a few seconds.

When in turbo, or 100% assist it appears to run more smoothly.

Does anybody have an idea of what the problem could be?

thank you.

 

[E-HP]

I have an Evo pro jet 2018 model, that in all appearances looks like new.

There are four "speeds" Eco, Normal, Sport and Boost
The problem seem to be that when peddling, especially in the three lower speeds the motor appears to cut out. The action of the pedals to power is not smooth but putting more pressure on the pedals the motor kicks in again and then sets out. Kind of like bursts of power that last for a few seconds.

Did you get the bike used, or are you just proud of your bike maintenance ? If you got it new, has it always had the same behavior?
I’d guess that the “speeds” may actually be speeds or set power levels so the controller just stops assisting when hitting that limit. The bike has a torque sensing PAS, and doesn’t measure cadence, so reacts proportionally to pedal pressure/effort. If you don’t maintain chain tension, no assist. Some systems will have an adjustable delay to keep PAS assisting when you stop pedaling in order to be less on or off, but that would be rare on a factory bike.
Is there anything wrong with just leaving it on boost?

 

[rick_p]

The bike has a torque sensing PAS, and doesn’t measure cadence, so reacts proportionally to pedal pressure/effort. If you don’t maintain chain tension, no assist.

I have a bike around the same year (see my profile picture) that behaves similar to what you (original poster) described, and I think E-HP has it right, I think this behavior might just be the torque sensor trying to do it’s job. In my case, I think the sensor is wearing out, and therefore exacerbates the early cut off of power before I fully decrease the pressure on the pedals. You may be experiencing the same sort of issue. Mine also seems to work a little better at the highest setting, so I do exactly as E-HP suggests, I just keep it there most of the time, or run in throttle only mode.

 

[John g]

Did you get the bike used, or are you just proud of your bike maintenance ? If you got it new, has it always had the same behavior?
I’d guess that the “speeds” may actually be speeds or set power levels so the controller just stops assisting when hitting that limit. The bike has a torque sensing PAS, and doesn’t measure cadence, so reacts proportionally to pedal pressure/effort. If you don’t maintain chain tension, no assist. Some systems will have an adjustable delay to keep PAS assisting when you stop pedaling in order to be less on or off, but that would be rare on a factory bike.
Is there anything wrong with just leaving it on boost?

First I wish to thank you both for your prompt reply's, I really appreciate it.

I bought the used bike for my wife about six months ago and it was in mint condition so I was just trying to give an idea of the former owners maintenance. Always in doors and so on so that the general wear and tare could be considered in possible diagnosis.
I have had several E bikes, although none with this particular pressure sensor system, all of which ran smoothly in relation to pedal motion and "speeds". Maybe we just have to get used to it or as suggested always run in boost. I just find it annoying that the motor, and pedals do not run smoothly and in conjunction.

I think , as you both suggest that the speed are set power levels, as they seem to be percentages of power 30, 50, 70 and 100% on the display, as it does not actually say Eco, Normal, Sport or Boost on the display. But does give these values in the manual.

Rick, you said that you thought that your sensor was wearing out.
Might it be possible that this could be my problem, exacerbating the experience of "a stuttering" motor?
And, do you think that putting in a new sensor might alleviate or reduce the problem?

I would not have a problem changing the sensor myself, as I took the old one out to see if maybe it was blocked or affected by dirt, which it wasn't.

Thank you both again for your replies, much appreciated.

John, from Denmark, Europe.

 

[stancecoke]

I would not have a problem changing the sensor myself, as I took the old one out to see if maybe it was blocked or affected by dirt, which it wasn't.

With the TMM4 it is important to tighten all screws in the right order and with the right torque. There are many reports on that topic in the internet....

regards
stancecoke

 

[John g]

Thank you stancecoke,
I'll check that out

Regards
John