When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Hey all. I came across 2 (and a half) tao 110's which were not running. I have taken on the larger of the two as my first fix. The smaller is fully auto, the larger is a clutches manual.
After a day of chasing down wiring and fixing the kill switches, I still have no spark. Here is what I have figured out diagnosed thus far: (My responses in RED)
Is this a picture of your CDI?Yes, 5 pin CDI
Assuming the answer is yes, the first thing to do is eliminate all kill switches and kill switch wiring:
Method 1) Unplug the CDI and remove the kill switch pin in the CDI connector on the wiring harness. The pin is held in with a spring tab on the pin itself. You'll have to probe into the connector and push this tab in order to extract the pin. Plug the CDI back in (kill switch wire dangling) and see if you have spark. No spark
Method 2) Unplug the CDI. Turn on the ignition switch and set all kill switches to the run position. Use a meter to measure resistance in of the kill switch pin in the wiring harness connector to engine/frame ground. If the reistance is infinite on the 100K ohm scale then your kill switches/kill switch wiring are OK. If you measure zero ohms then you have a kill switch/wiring issue. Infinite resistance, kill switches are all set
The other inputs your CDI needs to make spark are AC Ignition Power, and the Trigger signal. Do the following:
1) Unplug the CDI. In the wiring connector measure the resistance of the AC Ignition Power pin to the Ground pin. You should see 400 ohms or so. What do you measure? ~520 ohms, is this a concern?
2) Measure the resistance of the Timing/trigger pin to the ground pin. You should measure 150 ohms or so. What do you measure? INFINITE resistance! help!
3) Leave the CDI unplugged. Set your meter to measure AC volts on the 100 volt scale. Measure the voltage on the AC Ignition Power pin to the ground pin while cranking the engine. You should see 40 to 80 volts AC while the engine is cranking. What do you measure? Nearly 40, floats around 37v.
4) Set your meter to measure AC volts on the lowest scale you have. Ideally this would be 2 volts but many meters don't go down this low. In that case use the lowest scale you have. Measure the voltage on the Timing Trigger pin to the Ground pin while cranking the engine. You should 0.2 t0 0.4 volts AC. What do you measure? Around 0.1-0.2 v AC
Now for measuring the output side of the CDI:
A) Leave the CDI unplugged. In the CDI wiring connector measure the resistance of the Ignition Coil pin to the ground pin. You should measure less than 1 ohm (but not zero ohms). What do you measure? 0.5 ohms.
B) Plug the CDI back in. Set your meter to measure AC volts on the 20 volt scale. Set all kill switches to the run position. Crank the engine while measuring the voltage on the Igntition Coil pin to ground. Poke through the insulation of the wire if you can't probe the connector.0.00! No spark pinpointed! Tried with 2 CDI units.
Caution: There should be moderately high voltage spikes on this wire. Make sure your fingers are not part of the circuitry. Don't touch the probe lead tips while doing this test.
What you should see is a lot of random numbers with lots of zero values as well. This is because the meter may catch all or part of the spark event voltage, with a lot of nothing in between. Describe what you see.
Note: Using a meter to measure this point produces highly variable results depending on the meter. What you really need is an oscilloscope, but most always a meter is all that is available. We have to do the best we can with what's available. Describe the meter results as accurately as you can - there is information there to chew on....
So in summary,
1) Timing/trigger pin to the ground pin (on wiring harness I assume) is infinite resistance, not 150ohms as expected.
2)CDI plugged in, Igntition Coil pin to ground while cranking shows all zeros (though it does jump from -0.00 to 0.00, so it is interacting. Also, a few of the times I ran this test I would get one spike of ~20v right as I let off the cranking switch)
What should I try next? Recall, I have an extra parts bike to swap pieces over with, so all suggestions are welcome.
Well took on the smaller one this afternoon and had it running in no time. This leads me to believe that all the components I had switched around are likely okay.
I did notice that the smaller one cranked MUCH more quickly, which has me wondering if the larger one is simply not spinning fast enough to produce a spark. I have a third starter which I will switch on to the larger quad and see if that helps it out.
if it ain't turning over fast enough, how much of a draw is the starter pulling across the solenoid from the battery? is it pulling too many amps and killing it? test out the voltage around that entire circuit.
Sorry I'm a bit lost in what you're asking. When you say "killing it", are you asking if the starter stops spinning? If so, no, it keeps spinning, just not too fast.
I am jumping this off my healthy truck battery, not an onboard battery, before that gets asked.
I believe the starter itself is causing the slow rotation (and likely drawing a lot more amps than it needs to). I say this, because when I first went to turn the engine over, the starter wouldn't give. I tore it down and found a single coil of wire had come loose and bound up the actual motor. I cleared this up, but I'm now thinking that the lost coil may be to blame for the decreased RPM.
I'll just toss on the extra starter I have to clear that up.
As far as the no-spark issue (if the slow starter speed is not to blame), can anyone comment on the results I posted above to the tests?
1) Timing/trigger pin to the ground pin (on wiring harness I assume) is infinite resistance, not 150ohms as expected. [This is a Big Red Flag. This is not right at all. Find the timing trigger wire on your CDI connector and note it's color. Now go down to the stator and find the same wire color on the wiring harness side of the stator/wiring harness connector set. This will be the other end of the same wire from your CDI connector. Unplug that connector. Now measure the resistance of the timing trigger wire looking into the stator (on the wire going into the the engine) relative to engine ground (or use the ground wire on the CDI connector - they are the same thing). Does this connection still read open? If so your stator is bad. If it reads 150 ohms or so then your wiring between the stator and the CDI is bad.]
2)CDI plugged in, Igntition Coil pin to ground while cranking shows all zeros (though it does jump from -0.00 to 0.00, so it is interacting. Also, a few of the times I ran this test I would get one spike of ~20v right as I let off the cranking switch) [When the timing trigger signal between the stator and the CDI becomes open, a very common symptom is no spark while cranking but a single spark is generated at the beginning of engaging the starter motor and/or when the starter is disengaged. This is because enormous transient voltages are generated when switching large currents on or off, and these couple into the CDI trigger wire and can trigger "one" spark.]
What should I try next? Recall, I have an extra parts bike to swap pieces over with, so all suggestions are welcome.
-Rich
[All indicators so far are pointing to the timing trigger signal, and also are pointing to the fault being closer to the stator end of things rather that at the CDI end of things. ]
Unfortunately I'm working through the weekend, so won't have a chance to test this out till Monday. However, I can say that I did try the stator cover from the smaller quad (now verified as functioning) and did not see a difference. This makes me hopeful that it is the wire from the CDI down to the stator.
I did, however, test continuity of all the wires from the CDI, voltage regulator, stator, etc.. and they were all perfect... including the one in question. So who knows, I'll see what I can figure out come Monday.
Thanks again. As always, I'm amazed by how vast of a resource forums can be.
Luckily came across this thread as the troubleshooter was the best I found. I had an Tao Tao 110 ATV with no spark. I was trying everything but could not get spark.
I finally found the problem, but, it's still a bit of mystery for me.
There are three mail kill switches on the ATV(excluding ignition):
1. Handlebar kill switch.
2. Tether Kill switch
3. Remote Kill Switch (may be excluded on some models).
Using the troubleshooter listed in this thread I disconnected the Kill Switch line from the CDI connector block thus eliminating all kill switches. Checked for spark and got a spark, whoo hoo. Unfortunately it wasn't so cut and dry.
With the Kill Switch line removed I checked for continuity from all 3 kill switches. All three switches properly grounded out (continuity). Scratching my head, I connected the kill switch back up to the CDI and checked for spark, no spark.
Ok, wtf. Removed all the kill switches a second time and methodically checked each grounding for each kill switch all the way back to the CDI terminal connector. Again, each switch fully checked out with continuity to common ground. When enabled, they created continuity, when open, no continuity.
Decided to walk each connector back and instead of using my voltmeter for continuity I decided to check for spark instead.
1. Connected the tether kill switch, check for spark, got spark.
2. Connected the Remote kill switch, checked for spark, got spark.
3. Connected handlebar kill switch, checked for spark. No Spark.
Aha, found it, but, when I checked ground continuity again the voltmeter would not ohm out. I went ahead and took apart the handlebar kill switch and took a nail file and tried to make sure there was no "arc" between the switch contacts.
What I concluded is that there was a "jumping" ground somewhere in the kill switch or the kill switch connector at the handlebar kill switch. That is wasn't enough to cause the voltmeter to show continuity but it was enough to reroute spark to ground effectively killing the motor.
I took apart the Handlebar killswitch connector, checked all the plugs for any possible shorts and filed a small gap in the switch itself. Hooked everything back up and got spark with all kill switches connected.
I should also note, I have a Tao Tao 125 which shares all the same electronics. So, after checking kill switches with my voltmeter the first time through, I went and replaced all the electronics with my Tao Tao 125 to try to see if I can find the electrical component that was failing. After all of them checked out, I went back to the kill switch issue and because I walked each combination through I found my issue.
Honestly tho, I'm still not 100% sure what was going on with the handlebar kill switch wiring. It was just enough to kill the spark on the quad but not quite enough for my voltmeter to detect it...
But the funny thing to me is if you jump it with a little 12v jump starter from the starter it has a great spark at thr plug, but if you jump it from the battery which is bad but from where you are Suppost yo jump something it has no spark. Can you plz help I don't understand I dtove it for a weeks with my son had to clean thr carb once but other than that didn't even have to choke it most days. I rode it up in the building hit the handlebar kill switch and when I went out the next say to start it nothing.I Checked for spark and noticed it wasent getting spark I tried a few things and for some reason with thr plug out but in the coil wire turned it over putting the cables on the starter and the plug sparked like crazy?? Can somebody please help!!!
I have a TaoTao 110 four wheeler that I ain't getting any Spark to my spark plug I have power to my battery I have lights I just need some help trying to figure it out already check the fuse and a connection I don't know what it is
09-13-2012, 02:16 PM
Tao Tao 110cc, No spark, diagnosis completed
