Kymco People GT 300i ABS No-Spark Issue – Need Advice on Troubleshooting

[angeloK]

Angelo, sorry to say there is no other way than to go trough all procedures as you would have a completely unknown vehicle.

Start with:  seat, undertray, tupperware off completely
-all switches
-all relays (out and clean and benchtest)
-all fuses (out, new)
-coil. cable, sparkplug
-all groundpoints, behind starter motor
-KILLSWITCH
-connectors within middle tunnel

Write down every little step, even cumbersome.
Like said, big parts mostly don't fail.

Thank you for your kindness and your patience, as always.

I'll go through every little things, again. In the meanwhile I tested the spark at the coil and it does work. https://gifyu.com/image/bbool

I'm sure, like you said, that is something minor, like some switch. At the moment I can see the signal from pick-up (also tried to switch cables, as I read about it online) coming to the CDI.
I also see that the CDI is sending some signal to the coil while cranking, but this signal does not trigger the spark. I can say that because the voltage between signal cable and ground is around 11.5V, dropping to 9V while cranking (Battery 12.5V).

I'm thinking about buying an oscilloscope, this scooter is costing me more than a new one 

[Ruffus]

Please try to jumpstart from a car battery,
- both brake switches work (light)?
- car idling,
- NO throttle (acelleration stop mechanism)
maybe it works with this little bit more of voltage? Our ECUs are pretty sensitive on  low DC.

[angeloK]

Hello! Here's the update 

First of all, some pic of the tests. Tried to start with car in idle and benchtested all the relays (activation and continuity). I can hear them work if I short circuit the switches when the key is on, they are definitely working.

To answer all the questions I re-run all the tests again:
- brake switches are ok, otherwise the starter motor would not work.
- side stand switch, same story. Bypassed, otherwise no starter motor.
- fuses, all renewed.
- all groundpoints at the chassis, cleaned, tested continuity with chassis and their endpoints.
- killswitch bypassed, otherwise no starter motor.
- tilt/roll switch, disassembled completely, cleaned and tested. It gives in output 0.9V which is exactly in spec.
- didn't find the connector within tunnel, but tested each single wire in continuity from source to destination.
- pickup signal coming to the CDI connector is OK.
- power to the ignition coil is OK. Tried to manually short the coil ground to the chassis and I can see the spark at the spark plug.

What I can see is that the green/brown from CDI to the ignition coil, which should send the signal (put it to ground for a short instant when the pickup reads the magnet) is correctly connected to the CDI and receives some sort of signal, but no spark. Bought an oscilloscope!

Also, I took a look at the downtown service manual, which has dedicated pages to ABS ECU, but I didn't find any correlation between ABS and Ignition.

Last bit, which may be very important, is the TPS. It is illustrated in the ignition system diagram, why?
Could a bad TPS cause no spark?
The service manual says its resistance must be something from 3500 to 6500 ohms but mine is more about 1000 (fully closed) to 2000 (fully open) ohms.
It seems to work, because through the TPS I reset codes of the ECU multiple times.

What do you think about it?

Thanks 

[Iahawk]

really impressed with all the work you're doing to fix your scoot! Impressive skill set. I just wanted to comment on your garage floor. Looks great. Is that ceramic tile made to look like wood flooring? Good luck with your scoot.

[Ruffus]

...scratching scalp🤔
 Tried to manually short the coil ground to the chassis and I can see the spark at the spark plug.

-means coil is loading and discharging, so it gets juice

Also, I took a look at the downtown service manual, which has dedicated pages to ABS ECU, but I didn't find any correlation between ABS and Ignition.

-don't think ABS is causing this in any relation

Last bit, which may be very important, is the TPS. It is illustrated in the ignition system diagram, why?
Could a bad TPS cause no spark?

-since we have to claw any last straw, yes, it could cause a malfunction
Try to change the sensor with a known good used one if possible.
Honestly I have to admit, I don't know, but still think we just missing something anyway clear piece malfunction like a cable, connector, plu, ect.

[angeloK]

really impressed with all the work you're doing to fix your scoot! Impressive skill set. I just wanted to comment on your garage floor. Looks great. Is that ceramic tile made to look like wood flooring? Good luck with your scoot.

Hi! Thank you for your compliments 

The floor should be what in Italy we call "gres porcellanato", I think the english for it is porcelain stoneware!

[angeloK]

...scratching scalp🤔
 Tried to manually short the coil ground to the chassis and I can see the spark at the spark plug.

-means coil is loading and discharging, so it gets juice

Also, I took a look at the downtown service manual, which has dedicated pages to ABS ECU, but I didn't find any correlation between ABS and Ignition.

-don't think ABS is causing this in any relation

Last bit, which may be very important, is the TPS. It is illustrated in the ignition system diagram, why?
Could a bad TPS cause no spark?

-since we have to claw any last straw, yes, it could cause a malfunction
Try to change the sensor with a known good used one if possible.
Honestly I have to admit, I don't know, but still think we just missing something anyway clear piece malfunction like a cable, connector, plu, ect.

I had already did the coil test  with the CDI powering the coil and shorting it to the scoot ground and it sparks. The oscilloscope came but I didn't have the time to measure the signal yet!

Thanks for the confirmation about ABS 

My though is the same as yours, it is something very, super stupid. And yet... I'll do some other test!

[Ruffus]

Angelo, read and reread all from beginning: Did not  read you checked the ignition switch.

Is the ignition switch (keyswitch) correctly cabled? The multi connector from there coming.
Unplug, check according to wiring diagram and reconnect  (🤔 just guessing).

[angeloK]

Angelo, read and reread all from beginning: Did not  read you checked the ignition switch.

Is the ignition switch (keyswitch) correctly cabled? The multi connector from there coming.
Unplug, check according to wiring diagram and reconnect  (🤔 just guessing).

I guess I'm really lucky to have someone's care like yours in this trip! I truly thank you!

I checked it once, I jumped the cables coming to it (black and red) and give it a try. It was like the key was in ON position.

Any other check i can do? I see there are just 2 cables coming to it but there are 6 connectors on the switch.

[Ruffus]

Any other check i can do? I see there are just 2 cables coming to it but there are 6 connectors on the switch.

Don't know exactely which peculiar switch is in your scoot, but its worth to try to change this pins.
We will find the culprit.

[angeloK]

Hello! I didn't had the chance to work on the scoot lately, but I received an offer from an ebay seller for a complete electrical harness I had on my cart.

Do you think I should try it for 35€?

[Ruffus]

Why not, there's been so much effort invested already, this €35 ,- would not harm.
But be sure its from the same year. There are sometimes small changes.

[angeloK]

Here is the test with the oscilloscope!

https://mega.nz/file/GptFRChT#APzATcGooJn6AJ77lIw91OIENDk1bEPGrHmXMqKStOI

This should be the signal from ECU to the ignition coil. Honestly, I was expecting something completely different, I don't even know how to read this signal I got in output.

[Ruffus]

Sorry, cannot say anything about without comparison parameters.
This LH seems to be the alternator side, RH I cannot interprete.
Maybe somebody with more experience in this field chimes in.
But maybe the used harness brings some enlightening?

[angeloK]

Hello everyone! 

We finally got it sorted, kinda 

The good news is that I managed to see the f****g spark on the plug!! I'm super happy, thank you Ruffus for your precious support!

The bad news is that maybe all the tests and parts bought were useless.

The problem seems to be on the rotation speed of the engine during the crank phase. In fact, in an enlightened moment I had the idea to use a drill at the maximum speed to rotate the engine through the flywheel nut, instead of using the starter motor.
Since I have bypassed EVERYTHING there was no need to press the brakes or press any switches. It immediately fired the spark at the spark plug! My mouth was wide open for a good minute, in silence and immobilized 

I think I'll keep the new stator, pickup and coil on, they are new and original and I see the replacement as part of a "preventive" maintenance.

More to come on the disassembly and inspection of the starter motor, all my guess are on it because I tried all kind of different combination of batteries (even with car idle) and never never got the engine to rotate at the right speed to fire the spark!

Sorry this message can be confusing, I first saw the spark friday but I'm still super excited! Thank you truly for the support!