Help! Intermittent loss of motor power

[spuddle]

Hi
Looking for suggestions on a problem I have.

I bought a used PULSE Z2 a couple of months ago and it has this intermittent loss of motor power. The motor is the rear hub type 250w brushless, and the PAS looks like a 4 wire - drive crank mounted disc (12 magnets) and pickup. No brake lever feedback or throttle fitted.

Thus far I have dismantled the hub motor and re-greased it (only because the grease was old) and generally cleaned it up. Cleaned and checked the position of the magnetic PAS disc on the drive crank. Checked and re-seated all the bikes controller cables. Checked the battery connectors for good contact.

When mounted in a bike stand the motor seems to run sweet with no issues.

However when I am riding the power seems to blip intermittently as if the motor has stopped driving. The bike has three power levels and the blip is most noticeable when in the highest drive . Sometimes it will clear if I momentarily pedal backwards and I hear a slight noise, but this may be irrelevant.

My inclination is towards changing the PAS sensor. However most of the ones advertised are 3 wire ones, which would presumably fit on the non drive side of the crank, and I am unsure of the effect on the controller, if any, of replacing the 4 wire one.

Any suggestions would be welcome.

 

[Andy-Mat]

Hi
Looking for suggestions on a problem I have.

I bought a used PULSE Z2 a couple of months ago and it has this intermittent loss of motor power. The motor is the rear hub type 250w brushless, and the PAS looks like a 4 wire - drive crank mounted disc (12 magnets) and pickup. No brake lever feedback or throttle fitted.

Thus far I have dismantled the hub motor and re-greased it (only because the grease was old) and generally cleaned it up. Cleaned and checked the position of the magnetic PAS disc on the drive crank. Checked and re-seated all the bikes controller cables. Checked the battery connectors for good contact.

When mounted in a bike stand the motor seems to run sweet with no issues.

However when I am riding the power seems to blip intermittently as if the motor has stopped driving. The bike has three power levels and the blip is most noticeable when in the highest drive . Sometimes it will clear if I momentarily pedal backwards and I hear a slight noise, but this may be irrelevant.

My inclination is towards changing the PAS sensor. However most of the ones advertised are 3 wire ones, which would presumably fit on the non drive side of the crank, and I am unsure of the effect on the controller, if any, of replacing the 4 wire one.

Any suggestions would be welcome.

Possibly chain slip, maybe due to the derailleur spring that keeps the arm back is too weak (did you maybe de-adjust it?), or the chain and gears are worn, or even both?
On my previous e-bike with Shimano gears when it got to about 3 years old (high mileage though), it started doing the same and dropping the chain off as well. I tried everything including a new chain, nothing helped for long!
I eventually bought a no-name new rear 8 gear cluster (ebay) and not only did I have a slightly higher top gear , but all the "shenanigans" were also fixed!
Not expensive either from ebay.
IMHO, it was actually of better quality than the Shimano stuff it replaced! It has made me appreciate that some Shimano bits are often made "down to a price!"
Regards
Andy
PS. A thought, did you replace the chain with a longer one? Alays count the links and order the same number.

 

[vfr400]

4-wire PAS is quite rare. The ones I've seen didn't have the 4th wire connected inside the controller, and two identical controllers had different the signal wires connected.

I doubt that the PAS is the cause of the cutting out. First thing to eliminate is the max speed cut-out at 15 mph. What speed does it cut out at? The next thing is the battery. Do the battery indicator LEDs go out when it cuts out?

 

[spuddle]

Possibly chain slip, maybe due to the derailleur spring that keeps the arm back is too weak (did you maybe de-adjust it?), or the chain and gears are worn, or even both?
On my previous e-bike with Shimano gears when it got to about 3 years old (high mileage though), it started doing the same and dropping the chain off as well. I tried everything including a new chain, nothing helped for long!
I eventually bought a no-name new rear 8 gear cluster (ebay) and not only did I have a slightly higher top gear , but all the "shenanigans" were also fixed!
Not expensive either from ebay.
IMHO, it was actually of better quality than the Shimano stuff it replaced! It has made me appreciate that some Shimano bits are often made "down to a price!"
Regards
Andy
PS. A thought, did you replace the chain with a longer one? Alays count the links and order the same number.

Hi Andy
Thanks for the response. I did a complete strip down of the drive system after I bought it, cleaning the chain and jockey wheels. I also replaced the freewheel cassette as the original was running rough. However problem still existed after all put back together and adjusted.
regards

Frank

 

[spuddle]

4-wire PAS is quite rare. The ones I've seen didn't have the 4th wire connected inside the controller, and two identical controllers had different the signal wires connected.

I doubt that the PAS is the cause of the cutting out. First thing to eliminate is the max speed cut-out at 15 mph. What speed does it cut out at? The next thing is the battery. Do the battery indicator LEDs go out when it cuts out?

Hi
Thanks for the response
Appreciate what you are saying about the 4 wire being uncommon, but unfortunately the controller is the sealed type so you cannot tell if all the 4 wires are connected as the cable goes into the plastic sealant. I did send a query to EBCO, who made the bike ,asking if the 4 wires were all used but they never responded.

I haven't monitored the actually cut off speed as it has appeared random and instantaneous, but I will look into it now. The battery leds on the handlebar controller remain constant evening when the power blips.

thanks

 

[Andy-Mat]

Hi Andy
Thanks for the response. I did a complete strip down of the drive system after I bought it, cleaning the chain and jockey wheels. I also replaced the freewheel cassette as the original was running rough. However problem still existed after all put back together and adjusted.
regards

Frank

Sad.....that is an easy one to fix.....
So do you think it might be electronics, a bad or corroded connection? Or even a dry joint in the soldering somewhere....?
regards
Andy

 

[vfr400]

It's a shame you didn't mention this before the bike show because I had a long chat with the Ebco guys and I've known the owners since 2011. I've been out for a bike ride with them. They have some nice new bikes with the tiny Bafang cassette motor.

Back to your problem. The only thing I can suggest is to check any connections between the controller and the motor very carefully and make sure that the 9-pin connector is in all the way to the marked line. If it only cuts out at 15mph, that's the normal max speed cut-out, but that should be obvious.

 

[barbel]

Hi
Looking for suggestions on a problem I have.

I bought a used PULSE Z2 a couple of months ago and it has this intermittent loss of motor power. The motor is the rear hub type 250w brushless, and the PAS looks like a 4 wire - drive crank mounted disc (12 magnets) and pickup. No brake lever feedback or throttle fitted.

Thus far I have dismantled the hub motor and re-greased it (only because the grease was old) and generally cleaned it up. Cleaned and checked the position of the magnetic PAS disc on the drive crank. Checked and re-seated all the bikes controller cables. Checked the battery connectors for good contact.

When mounted in a bike stand the motor seems to run sweet with no issues.

However when I am riding the power seems to blip intermittently as if the motor has stopped driving. The bike has three power levels and the blip is most noticeable when in the highest drive . Sometimes it will clear if I momentarily pedal backwards and I hear a slight noise, but this may be irrelevant.

My inclination is towards changing the PAS sensor. However most of the ones advertised are 3 wire ones, which would presumably fit on the non drive side of the crank, and I am unsure of the effect on the controller, if any, of replacing the 4 wire one.

Any suggestions would be welcome.

i have the same fault .did u find a fix

 

[Heen]

I have this exact same problem too and none of the local bike shops are able to suggest anything except to replace controller, motor and battery one after the other, by which time I may as well have bought a new bike! This seems to be a common problem with this bike - if anyone has found the answer I'd love to know, as I am currently struggling to keep riding my non-electric model

 

[saneagle]

I have this exact same problem too and none of the local bike shops are able to suggest anything except to replace controller, motor and battery one after the other, by which time I may as well have bought a new bike! This seems to be a common problem with this bike - if anyone has found the answer I'd love to know, as I am currently struggling to keep riding my non-electric model

What sort of battery charge indicator do you have? What does it do just before the cut-out? Does it stay steady, showing a full battery, or does it go down?

 

[Heen]

Goes from full charge to zilch

 

[Heen]

Though not straightaway, and when tested apparently hasn't lost much voltage

 

[spuddle]

Hi
If memory serves me I ended up changing the hall sensors in my motor. Unfortunately while taking the motor apart I managed to damage the clutch mechanism on the motor. I ordered one from china but did not realise there are different direction clutches, and of course I ordered the reverse clutch to mine! I fitted it on the motor and it ran perfectly - except backwards. Anyway I gave up and bought a complete kit of wheel, motor, controller and pas sensor. I sold the rebuilt bike and the original recovered parts.
I went on to build my own e-bike using a Carrera crossfire 3 and a Yose power kit. I still have it and it works well.

 

[saneagle]

Goes from full charge to zilch

If it goes down just before cutting off, your battery is knackered.

 

[Heen]

Thank you, I've found a bike shop who are willing to take a look so I can give them some clues...