engine cranks but no spark; blinkers going crazy

[societyofrobots]

edit: skip down to here for the current status/summary
https://www.kymcoforum.com/index.php?topic=33917.msg237955#msg237955



My Super 8 150 has two issues that are probably unrelated, but I've failed to figure out how to fix either.

The first issue is my rear left blinker blinks hyper fast, while the front left blinker has stopped blinking. And sometimes, but not lately, a similar thing happens to the right side. This had been an issue for the last two weeks.

The second issue is that now it won't start. It cranks like a champ, fuel is flowing into the carb, but no visible spark from the spark plug. That said, if I hold the plastic connector with the spark plug in my left hand, and squeeze the metal breaks in my right hand while starting the engine, I'll receive a sudden electric shock to my left hand directly through the plastic. I was driving the bike fine the night before, and the next morning it refused to start again.

In my attempt to fix it, I've replaced the 12V regulator, replaced the light controller (assm?) box, replaced the CDI, replaced the spark plug, battery is good and fully charged, replaced fuel lines to transparent lines and can see fuel flowing, replaced vacuum fuel pump, and replaced the filter.

My theory now is maybe a blinker light has a short or the cable harness is bad, causing a grounding issue. But, haven't attempted to address this yet. Everything else electrical on the bike is working great.

Any ideas?

I'm no mechanic. My background is in designing circuit boards so that's gotten me about this far....


edit: Maybe not relevant, but the kill switch seems to have no effect. It cranks and everything electrical turns on regardless of the kill switch position.

[Stig / Major Tom]

A rapid turn blinker means your other bulb on that side is burned out.
Some kill switches permit everything but a start. Cranks just like it is going to start - but doesn't.
Key on, brake lights must light when brake lever squeezed or scoot will not start.
Not working?, often the brake light switch behind brake lever
has failed...or is dirty. Spray cleaner....

Stig

[Ruffus]

@societyofrobots welcome here!
Blinker issue as already said by Stig, check bulbs and relay.

Starting story:
-kill switch is nurtured by two cables green/ white I guess
-unscrew this item, clean and short this two cables with a needle
Starts?
Yes, then clean again and remove corrosion

No? squeeze left hand brake lever to start
No?
- pull off this two small 4/6mm connectors of one of your brake light switches, clean and connect them
-ignition on
-brake light on?
Starts?

Replace sparkplug cap.and cable.
Pls come back for questions or feedback.

[societyofrobots]

Brake lights works fine for both left and right handles. So that's not it.

Kill switch works fine, tested it with a multimeter. Leads are in perfect condition. So that's not it, either.
(kill switch used two identical black/blue wires)

Spark plug still isn't sparking.

Replace sparkplug cap.and cable

I just ordered this, will arrive on Monday.

The current spark plug cable looks good, great condition. Let's say it still doesn't work after replacing the spark plug cable, what else could it be?

Only the front left blinker isn't working, and it wasn't working for a week before this spark plug issue. Safe to assume it's unrelated? I'm trying to replace the blinker with an LED version.

[Ruffus]

..after new sparkplug and cable..
- spark there on the plug?

If YES, is fuel coming into cylinder?
- sparkplug in and crank
- sparkplug wet?
Since it worked before you left it overnight, there cannot be that many culprits.
Spark and fuel, there I would search..

[societyofrobots]

Quick update... I used my multimeter to measure the resistance on the two sparkplug cable wires and got 2kohm for each. I believe it's supposed to be near 0 ohms, so it's likely the problem. Will confirm when the new part comes in.

Also, I checked the starter solenoid and that's working fine.

is fuel coming into cylinder?

Yes. I replaced the vacuum fuel pump and used transparent fuel lines to verify.

[societyofrobots]

Replaced the spark plug cable.

Still does not spark. Ugh.

Old cable measures 0.4 ohms and new one 0.5 ohms. Should have checked that before...

Interestingly, on two separate occasions, the spark plug made a single spark. Once before I replaced the cable, and once after. I've been unable to replicate it.

The stator has three wires. I measured resistance, and the two wires (pink and yellow) on the single connector measure 0.7 ohms between them, and the third independent blue/yellow wire (pickup coil?) had infinite resistance with everything else.

Does this mean a pickup coil issue?

[Ruffus]

IMHO try another approach..
If noone has been in this stator/ rotor I think it as a low possibility to hv a faulty pickup sensor.

As a sparkplug cable can be used anything. Resistance here is not that significant.

Your stator should have three yellow cables (coming out from you RH upper motor side) which lead to a connector where your rectifier is cabled to.

THERE is sometimes a broken cable or rotten connector. Check there.
Pls see att link for your scoot.

Plz see wiring diagram for your scoot.
Check whether its according this diagram on your scoot.

I suspect sparkplug cable not fixed properly or ignition coil faulty.
Sparkplug really functional?
Sparkplug cap new?
Follow from there.

Also still think smtg ongoing with either brake light switches, killswitch, starter switch and smtg in between this and coil.

Pls see link below. Chapter 14 is electrics...in this WS manual...
https://www.google.com/url?sa=t&source=web&rct=j&opi=89978449&url=https://scootergrisen.org/scooterhjemmeside/download/kymco_super8_4t_servicemanual.pdf&ved=2ahUKEwip2Lud39KDAxUqhP0HHfu2B6YQFnoECCEQAQ&usg=AOvVaw108wqNUjos6KnnQWJGzE6K

[societyofrobots]

Let me re-clarify everything on steps I've taken to debug it.

It cranks, but 99% of the time no spark. It's sparked randomly on two separate instances.

I've replaced all of these parts:
CDI
light assembly box (whatever that is near the battery)
right handle switch (including kill switch)
fuses
spark plug
spark plug ignition coil
spark plug wire + cap
rectifier/voltage regulator
the broken signal light

With a multimeter, I've confirmed that each of these work:
kill switch
pickup coil (111 ohms)
spark plug ignition coil (0.5 ohms)

The battery:
Fully charged and pumping out power like a champ.

The stator:
There are only 3 wires coming from the stator. A blue wire connected to the pickup coil, and a yellow and a pink both connected to the stator. There are no other wires.
The pink and yellow wires measure 0.7 ohms between them.

Brake lights
Brake lights on both sides turn on correctly when squeezing the break.

The CDI:
I disconnected the kill switch wire directly on the CDI as according to this video, but still doesn't work:

THERE is sometimes a broken cable or rotten connector. Check there.

Visually it all looks fine. I'll start probing everything today with a multimeter and report back.

[societyofrobots]

My Kymco has both of these.

Which one is the CDI, and what is the other thing?

The internet claims both is the CDI, which doesn't make sense....

[Iahawk]

My Kymco has both of these.

Which one is the CDI, and what is the other thing?

The internet claims both is the CDI, which doesn't make sense....

the one on the left in the pic sure looks like your lighting control module..it dims the headlight at idle and increases brightness as the revs climb.

(attached is pic of my lighting control module on my S200, circled in yellow)

[Ruffus]

There are only 3 wires coming from the stator. A blue wire connected to the pickup coil, and a yellow and a pink both connected to the stator. There are no other wires.
The pink and yellow wires measure 0.7 ohms between them.

This upper written confuses me a little bit.
Could it be you interchanged connectors there?
Cables to ignition coil correct?

As Iahawk writes, the right item is your CDI.
Was your stator/rotor side open?

Do you have a sidestand  switch? If YES, bridge this one, maybe there's the culprit?

-pls CONNECT all cables back on your CDI, opposing this video
-OPEN RH handle switch
-connect this two cables of your killswitch direct
-sand ignition coil connectors clean
-make sure ignition coil-cable-cap-sparkplug assambly is conductive
-renew fuses and check/ clean holders

Pickup Coil Check:
-unplug CDI
-multimeter on VDC
-MM dips into yellow/blue and green cable
-motor cranking
-should be low voltage (5-7V) shown on MM otherwise (00,1V) pickup coil faulty

Generator Check:
-CDI off blue/ yellow cable with MM black against ground
-MM on VAC
-cranking
-MM should show current  ca. 40 VAC

[societyofrobots]

This upper written confuses me a little bit.
Could it be you interchanged connectors there?
Cables to ignition coil correct?

blue/yellow wire -> connector #1 (pickup coil)
yellow wire -> connector #2 (stator)
pink wire -> connector #2 (stator)

I didn't change anything.

Was your stator/rotor side open?

What do you mean? I had never opened it before.

Do you have a sidestand  switch?

nope

-pls CONNECT all cables back on your CDI, opposing this video
-OPEN RH handle switch
-connect this two cables of your killswitch direct

The kill switch is confirmed to be functional.

-sand ignition coil connectors clean
-make sure ignition coil-cable-cap-sparkplug assambly is conductive
-renew fuses and check/ clean holders

All replaced with brand new parts.

Pickup Coil Check:
-unplug CDI
-multimeter on VDC
-MM dips into yellow/blue and green cable
-motor cranking
-should be low voltage (5-7V) shown on MM otherwise (00,1V) pickup coil faulty

I unplugged the CDI, put MM red on the blue/yellow from the pickup coil, and MM black on chassis ground.

For resistance I get 111 ohms. When cranking, I get 257mV.

Generator Check:
-CDI off blue/ yellow cable with MM black against ground
-MM on VAC
-cranking
-MM should show current  ca. 40 VAC

CDI is unplugged, MM red on the blue/yellow from the pickup coil, and MM black on chassis ground. Correct?

MM set to VAC, cranking I get 0.25 VAC. Same voltage if I plug in the CDI.

Pickup coil faulty?

I get a new pickup coil in the mail tonight. I'll try replacing it asap.

[Ruffus]

Hmmmh,
gutfeeling says, pickup coil down.
Try with a new one. If not, last resort would be the stator. This is why I asked, whether somebody has been in this area, and demaged a coil in there...
I'm nearly at the poles end with my guess.

[societyofrobots]

I replaced the pickup coil, and the spark plug is now sparking! yay!
It's reading 150 ohm, and 0.256 VAC with the MM.

edit:
But, I had a clogged carb, so it still wouldn't start. Went to walmart for clog spray. But when I got back, the spark plug wasn't sparking again wtf.

Pulled out some hair, wiggled CDI/stator wires, unconnected and reconnected the CDI, then it just started correctly sparking again. I don't think it was the pickup coil, but some bad connection somewhere that I can't find. Ugh!

Anyway, I got the plug back in, and after some squirts of carb cleaner into the air intake, some patience, and a lot of black smoke from the exhaust, I finally got it to work. Yay!

Could the yellow and pink wires to the stator have a bad connection, maybe?