KymcoForum.com
Scooters - 125 to 300 => People GT 300i => Topic started by: angeloK on February 12, 2025, 10:14:13 AM
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Hi everyone,
I recently bought a Kymco People GT 300i ABS with a no-spark problem. The previous owner took it to a shop where they ran some tests and attempted to check the pick-up resistance (I can tell because they exposed part of the wiring). They convinced the owner to buy a new CDI, but it didn’t solve the issue.
Base Info:
- The engine is turning, and the starter motor works without any issues.
- The fuel pump is functioning but is currently disconnected.
- The battery is dead, so I'm jump-starting it using a fully charged car battery (13V).
Here’s what I’ve done so far:
- Confirmed the side stand is in the correct position and the engine stop switch is set to “ON.”
- Replaced the spark plug – still no spark.
- Tested the ignition coil resistance:
- Primary: 4.4ohm (manual states 3.57ohm - 4.83ohm)
- Secondary: 15.4Kohm (manual states 10.42Kohm - 14.49Kohm) – slightly out of spec.
- Checked the pick-up CPS resistance: 117ohm (manual states 115ohm ± 15ohm).
- Verified continuity according to the wiring diagram (attached).
- Inspected the tilt sensor, and each wire has continuity according to the diagram – Is there a way to bypass this for testing?
- Checked the engine stop switch at the relay end – it seems to switch correctly.
- Confirmed continuity between the ignition coil and ignition relay (both wires).
- Cleaned and checked ground connections on the chassis.
- Tested the stator phases – no shorts.
- Confirmed continuity from the stator to the rectifier and to the ignition switch.
- Tested the rectifier following a guide on YouTube – it seems okay.
Next steps:
- Measure voltage at the tilt sensor when the key is ON.
- Open the carter to inspect the stator.
Questions:
- What could be causing the no-spark issue?
- Which components could be bypassed to simplify the circuit and isolate the problem?
Any advice or insights would be greatly appreciated! 8)
Thanks in advance for your help! ;D
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@angeloK, welcome here!
Very thorough search already.
Sounds trivial but you didn't mention sparkplug cable?
Fuses all new?
I would:
-make a direct (temporary) cable between battery minus and engine (jump cable wth frogs)
-unplug, spray and plug this big connector between CDI and wiring harness
-take tilt switch off, bridge the cables
-unplug side stand switch and bridge
-ignition coil new?
-ignition coil cables (green and black?) in working order and connectors not worn?
-kill switch: open and bridge this white and green cable?
-jumpstart with a car "IDLING" to get more than 13.0 V on your scoots electronic
And always only ONE measure at a time!
See a dealer who has a DiagTool to borrow.
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@angeloK, welcome here!
Very thorough search already.
Sounds trivial but you didn't mention sparkplug cable?
Fuses all new?
I would:
-make a direct (temporary) cable between battery minus and engine (jump cable wth frogs)
-unplug, spray and plug this big connector between CDI and wiring harness
-take tilt switch off, bridge the cables
-unplug side stand switch and bridge
-ignition coil new?
-ignition coil cables (green and black?) in working order and connectors not worn?
-kill switch: open and bridge this white and green cable?
-jumpstart with a car "IDLING" to get more than 13.0 V on your scoots electronic
And always only ONE measure at a time!
See a dealer who has a DiagTool to borrow.
Thanks for the welcome :)
- Fuses not new, but just checked, sanded and cleaned with contact cleaner and tested continuity: they all seems OK
- Ignition coil and spark cable not changed, since I assumed the former owner and the shop would have tried this first already
- didn't make the direct connection, just seen you edited the message ;D
- cleaned the CDI connector with contact cleaner and re-tested all continuity: OK
- bridged tilt switch, side stand switch and stop engine (kill) switch
After all these measurement and bridges and so, I tried to read voltage coming to the ignition coil while cranking: NONE. 0V DC
So I checked the pick-up - as said, impedance is 117ohm - and read 0.7VAC, without oscillation between 0V and 0.7V. Is this ok?
If not, any way to emulate the pickup signal for the ECU?
Thank you for your thoughts! It helps a lot.
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Scratching head...
Since there is a new CDI, thats OK
I would take the syayor cover off and check the pickup cables.
For ignition coil I have my doubts, would renew the piece in one until sparkplug.
There where the pickup cables leave the engine, they brake sometimes in this rubber grommet...
Look at the wire harness once again and in this big
connector before CDI, check pins in there one by one..
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Scratching head...
Since there is a new CDI, thats OK
I would take the syayor cover off and check the pickup cables.
For ignition coil I have my doubts, would renew the piece in one until sparkplug.
There where the pickup cables leave the engine, they brake sometimes in this rubber grommet...
Look at the wire harness once again and in this big
connector before CDI, check pins in there one by one..
Thank you for your time, and your patience.
Maybe I wasn't clear enough before, the did TRY a new CDI, right now I'm stuck with the old one. I don't have a new one to try.
For ignition coil I have doubts too, but since it receives 0V from the CDI when engine is cranking, I put that out of the equation.
I'll check the pins of the CDI connector again, at the same time I'm trying to emulate the pick-up signal with an Arduino, let's see what's going to explode! ;D
Update: no news.
Tested the CDI connector, each wire has continuity as it should. Still no voltage at the ignition coil.
Tested voltage coming from the pick-up, but I read very low values (both AC and DC). I can't say if the multi-meter I'm using is able or not to read voltage at that frequency or if the pick-up doesn't send any signal.
I think it's time to open the pocket and purchase a stator + pickup :'(
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Hello again! Sadly, no good news :'(
I really don't want to give up on this!
I have a few more question to anyone of you has ever done this kind of tests before:
- Is the stator a possible culpript? As I understand from the manual and the scheme, it should not because the CDI is powered from the battery. But...
- Is there a way to measure the pick-up signal with a multimeter? I did buy a new one, tried but it changed nothing. It came to my mind that this one could be bad too, who knows.
I read the impedance of the pick-up and, as said in past posts, it's ok. I also put the multimeter to test continuity and it beeps when the flywheel rotates, so I assume the pickup sends something, but it is enough? It is the right signal?
I also checked all relays, tilt switch.
I can see I have power on the CDI, I have power at the ignition coil too (of which I tested the impedance and is ok).
How do I test if the ignition coil receives the signal from the CDI? I read something near 0.01xV as soon as I release the starting button and stop cranking. During cranking is 0V.
Any thoughts at all would make a difference here, avoiding driving myself crazy :o
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Hello again! Sadly, no good news :'(
I really don't want to give up on this!
I have a few more question to anyone of you has ever done this kind of tests before:
- Is the stator a possible culpript? As I understand from the manual and the scheme, it should not because the CDI is powered from the battery. But...
- Is there a way to measure the pick-up signal with a multimeter? I did buy a new one, tried but it changed nothing. It came to my mind that this one could be bad too, who knows.
I read the impedance of the pick-up and, as said in past posts, it's ok. I also put the multimeter to test continuity and it beeps when the flywheel rotates, so I assume the pickup sends something, but it is enough? It is the right signal?
I also checked all relays, tilt switch.
I can see I have power on the CDI, I have power at the ignition coil too (of which I tested the impedance and is ok).
How do I test if the ignition coil receives the signal from the CDI? I read something near 0.01xV as soon as I release the starting button and stop cranking. During cranking is 0V.
Any thoughts at all would make a difference here, avoiding driving myself crazy :o
The simple stator test is to slide a screwdriver along its magnets, each should be the same adhesion. Broken treads are nearly not to be seen.
Is it the correct pickup?
-reaches deep enough into?
Ignition coil test: put a weak (LED) 12V lamp on this two leading cables (coil mounted)
-starter, LED showing flicker?
-renew all fuses!
-cableshoes under fuses?
-sparkplug cable new?
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The simple stator test is to slide a screwdriver along its magnets, each should be the same adhesion. Broken treads are nearly not to be seen.
Is it the correct pickup?
-reaches deep enough into?
Ignition coil test: put a weak (LED) 12V lamp on this two leading cables (coil mounted)
-starter, LED showing flicker?
-renew all fuses!
-cableshoes under fuses?
-sparkplug cable new?
Maybe it is not the correct pickup, because the resistance is slightly over spec, but it looks the same and its position is fixed, as the old one. Anyway I tested both with a led and they look like working, both of them.
Fuses have been cleaned and tested. Did not check the cableshoes under fuses but checked all the continuity and they are ok.
As per the ignition coil I put a led at the black and green/brown coming from CDI:
coil unplugged --> led ON (11,02V) with key in ON position.
coil plugged --> led OFF, even if cranking. It just blinks before switching key to OFF.
Black (from CDI to coil) with ground: 12.6V (battery voltage).
I'm going crazy here. I think I'll buy a new stator, pickup, CDI and ignition coil all new ;D
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Sorry, don't know anymore remote.
Start with the less expensive to buy.
- coil with cable and plug (gutfeeling)
Or try to find a similar donor bike. Ok, chances are meager,...but
Or go somewhere to someone who lets you swap parts for testing, one by one.
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Sorry, don't know anymore remote.
Start with the less expensive to buy.
- coil with cable and plug (gutfeeling)
Or try to find a similar donor bike. Ok, chances are meager,...but
Or go somewhere to someone who lets you swap parts for testing, one by one.
Hi! I bought new coil with new plug, new stator with new pickup aaaaaaand no, no spark :(
Next step will be separate the CDI connector from the CDI itself, using a breadboard and running a direct cable from CDI to ignition coil. Also I will try to emulate the right functioning of the tilt sensor with some batteries.
Any other thought appreciated.
Ruffus, I read you are based in Italy, me too! Where? Would love to buy you a coffee :)
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Would try that one (see pic) if serial# matches
Extracting certain functions from a ECU goes beyond my knowledge and possibilities. But its worth a try.
Vivo a Friuli presso Udine.
BUT: I still think its smtg with one of the switches!
Either kill, sidestand or tilt.
Take apart the RH switch assy once again and put a needle trough both the kill switch cables.
Same game with sidestand etc.
ECUs fail very seldom, I personally did not have a faulty one. Heard only. So., check everything else again.
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ECUs fail very seldom, I personally did not have a faulty one. Heard only. So., check everything else again.
I'm one of those seldom then Ruffus! Twenty-ish years ago my old Triumph Daytona 955i died on me as a result of the ECU failing on an Autostrada just outside La Spezia! If memory serves it eventually got trailered to Numero Tre in Genoa, where a repair was completed in a few days and which Triumph UK eventually met the cost of despite the bike being 3 years old at that point! They clearly thought an ECU should last longer than 3 years too. First and only time I've ever had one fail.
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No doubt, the possibility is out there. Like I wrote, didn't see a KEIHIN ECU giving in.
But LUCAS, prince of darkness, is everywhere😅🛠.
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Hello!
As Ruffus said, CDI are not likely to fail, in fact it is not the culprit!
I ordered a second hand CDI, contacted the seller he told me it was kept from a crashed scooter.
Even with the "new" CDI, I have no spark.
After all the test I did, I changed stator with pulser coil (new), coil (new), cable (new), spark cap (new) and spark plug (new), CDI.
I bypassed all switches (brakes, kill, side stand, roll sensor). I deleted codes on CDI but still no spark. Checked thousand times the continuity of each cable, and they are ok.
What I can see is that the ignition coil receives power but does not receive the trigger to spark!
How is this even possible?
P.S. Ruffus I gotta say that the coffee has to happen online, 'cause I live in the far south of Sicily :)
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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.
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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) https://gifyu.com/image/bbool (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 ;D
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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.
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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 :)
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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.
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...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.
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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!
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...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 8)
My though is the same as yours, it is something very, super stupid. And yet... I'll do some other test!
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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).
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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.
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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.
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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€?
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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.
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Here is the test with the oscilloscope!
https://mega.nz/file/GptFRChT#APzATcGooJn6AJ77lIw91OIENDk1bEPGrHmXMqKStOI (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.
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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?
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Hello everyone! 8)
We finally got it sorted, kinda ;D
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 ;D
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! :D
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So the focus now shifts to the starter motor?
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This is good news👍👍! Congratulation!
So you encircled the culprit and brought 'em down.
I would never have thought of this option!?
Angelo, take a new aftermarket from Amazon, just look them up, they are inexpensive.
Make sure this groundpoint behind the startermotor is perfectely well.
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So the focus now shifts to the starter motor?
Yes indeed!
I already pulled mine from the engine, opened it and cleaned thoroughly cleaned. Gently sanded the brushes and contacts.
Obviously nothing changed ;D so I, again, pulled the trigger and bought one on Amazon.
Let's see what happens :)
The funny thing in this is that I don't even know if the engine is ok because I never heard the sound of it!
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The funny thing in this is that I don't even know if the engine is ok because I never heard the sound of it!
But you will, I am sure!
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Hello everybody!
Do we have a running engine here? YES, WE DO! 8)
Let me share the full story. I bought a new starter motor, very similar to the original... did it fix the issue? Of course not. But let's start from something I hadn't mentioned before.
As Ruffus wisely pointed out earlier in this thread about buying a used wiring harness:
[...]But be sure it's from the same year. There are sometimes small changes.
He was absolutely right. Here are the differences:
(https://imgur.com/4q1ynyql.jpeg)
Mine is the wide one (Euro3 spec)
The one they sent me was for Euro4 spec
Had to return it, but I knew the electrical system wasn't the real problem since I eventually got spark.
The focus then shifted to the starter motor. Bought a new one, installed it - but engine speed while cranking remained the same, still not enough for spark. I decided to close the crankcase anyway (stator and coil were good) and tried starting the engine with a drill. That didn't work because the spark plug created too much compression for the drill to handle.
Then I remembered the new battery I bought months ago for this scooter (the type where you need to pour acid in). Installed it and... the cranking speed became incredibly fast, even with the spark plug installed!
This made me question: did I really need a new starter motor? I tested the old one again and confirmed it's at the end of its life - it couldn't turn fast enough to generate spark with the plug in, though it worked without the plug.
What really confused me was that I had done countless tests with car batteries (even with cars running) and never got the starter motor to reach sufficient speed for spark. I suspect my jumper cables were trash and couldn't deliver proper current. They drove me crazy!
Here's a video of the first successful engine start:
https://mega.nz/file/Kt1W2SQa#gQf5CzcMeDIZau8nxoO17c2O9NvzSfiw_-2KuCmK28M (https://mega.nz/file/Kt1W2SQa#gQf5CzcMeDIZau8nxoO17c2O9NvzSfiw_-2KuCmK28M)
Turns out I did need the new starter motor, but it had the positive terminal in a different position compared to the original. As you can hear in the video, I couldn't install the airbox because of this.
(https://i.imgur.com/eeZAP6wl.jpeg)
My solution was to take both starters apart and swap the internals of the new one into the old housing:
(https://i.imgur.com/M9Z5aWol.jpeg)
Later I discovered this wasn't even necessary - you can just loosen the two screws holding the starter together and rotate the cylinder slightly. Who knew!
But wait, there's more! After the first test ride, I noticed the ABS activates immediately when using the rear brake (doesn't happen with the front). Removing the ABS fuse returns the rear brake to normal operation (without ABS intervention).
Any suggestions? My first step will be cleaning the ABS sensor (which means removing the muffler again ::)).
Thank you all for being part of this journey. I couldn't have done it without this community's help.
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Good move, sorry forgot to tell about moving the inner starter part. They all come with different angles.
But anyway, the scoot runs. This is what counts! 👍🛠
Concerning ABS:
-the sensors distance to this serrated disc is crucial
-try with different shims under the sensors bolt
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What a saga! So glad you got her running though Angelo.
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Hello!
Cleaned the ABS sensor didn't work, of course. I like it complicated.
I switched the front with the rear sensor trying to understand if the problem was the sensor or the ABS pump/ECU.
Switching the sensors did not brought any significant improvement, nor new problems. I expected to had the problem on the front but it was still the rear brake who had issues.
I put some shims under the sensor but it was rubbing against the disc so, in the end, I was looking to service the ABS pump but I first wanted to take a closer look to that phonic wheel (the serratic disc). It was slightly bent so I asked for the workshop chief help (the hummer) and put it straight. No more issues 8)
Now I think I need to service/replace the headset bearing because they have a strong point in the middle which makes the ride very unpleasant and dangerous.
Ride on!