I have a 150cc chinese dune buggy which I am getting no spark. I think I have narrowed it down to no voltage on the red and black wire coming from the stator. Does this mean that the stator needs replacing?

Also have a 2nd 150cc buggy which has voltage up to the CDI but nothing coming out on the Black w yellow stripe wire which feeds the coil. I have replaced the CDI and traced the kill switch wiring and still nothing.

Any help is appreciated. Thanks

 

On the first buggy, are you sure the "red and black" wire comes from the stator? Are you sure it is not black with a red stripe (a more standard color)?

The first thing to do on no spark quads (or buggies) is to determine if your CDI is AC powered or DC powered. I'm assuming you a a two connector, 2 and 4 wire CDI. Am I correct?

Here is a 2 plug 6 wire CDI:



The 2 plug 6 wire CDIs come in two different designs. One is powered off 12 volts DC, and the other is powered off a moderately high voltage AC which comes from the stator. Unfortunately there is no reliable way to tell the difference between the two by just looking at them. To be sure you need to use a meter to find out which you have:
1) Unplug the CDI, and turn on the ignition. Do not crank the starter motor. Use a meter to meausure the *DC* voltage on the pin labeled "AC ignition power" in the wiring harness to the ground pin in the same connector. If you measure 12 volts DC then you have a DC powered CDI.
2) If you don't measure 12 volts DC on the ignition power pin, then switch the meter over to measure AC volts on the 200 volt scale. While cranking the starter motor, measure the AC voltage on the "AC Ignition Power" pin to the the Ground pin. You should see 40 to 80 volts AC. If you measure AC voltage when the starter is turning then you have an AC powered CDI.
Using a meter is the only 100% reliable way to figure out if your CDI is AC or DC powered. But there are some clues you can use that are usually (but not always) correct:
A) DC CDIs tend to be a little larger than their AC powered counterpart. This is because the DC powered CDI needs a bunch more circuitry to convert the 12 volts DC to the moderately high voltage supply that CDIs must have.
B) Most (but not all) DC powered quad ignition systems do not use the kill switch input pin. The cDI connector pin usually has no wire tied to it. AC powered quad ignition systems usually do use the kill switch input pin.

After determining whether you CDI has power or not, the next step will be to measure the trigger signal, then the output to the coil.

 

Thanks LynnEdwards
So on the first buggy I replaced the stator and no have good spark, however it will only start when I completely cover the air intake on the carburator. Could this be an electric choke issue?

On the 2nd buggy i'll have to check again whether it is ac or dc powered although I have voltage into the cdi but nothing coming out on the wire which connects to the coil. I have tried disconeecting the kill switch wire at CDI still nothing, so I am out of ideas. I dont know what else to replace. I did notice the wiring harness has been spliced into in several places. I am wondering if I should replace harness to ensure all wiring is correct.

 

So you're running lean. I would not give high odds that the autochoke is the problem. These have a reputation of being trouble prone, though they almost always fail in the "choke on" mode. In other words the quad (whoops, buggy ) starts and runs fine, then runs worse as it warms up. There are tests for the autochoke here:

Troubleshooting

Choose the "electric choke" link...

But more likely you have clogs jets, or an air leak. 150cc machines are notorious for torn rubber intake manifolds. Be sure to inspect this carefully.

To me replacing the wiring harness is something I would never do unless there has been a major fire or something. Why not just find and fix the bad wire or two? I think that would be much simpler. There is no guarantee that your new wiring harness isn't going to have compatibility issues and make things worse instead of better.

You say you have voltage to the CDI, yet you don't know what the voltage should be (i.e. moderately high voltage AC, or 12 volts DC). I can see why you are having trouble . First find out if your CDI is DC powered or AC powered. At the same time you are doing this it will show if your CDI has power or not.

You've already proved the Kill switch wiring isn't the problem because you disconnected the kill switch wire at the CDI. The next step after verifying CDI power is to see if your CDI is getting triggered. Then look for pulses going to the coil. The plan is to measure as much stuff as possible to eliminate/confirm problems in these areas, then shotgun the couple things left that can't be measured.

And BTW, you will need a meter to do these measurements. If you are using a test light you're wasting your time. Meters are cheaper than test lights these days, and a whole lot more useful....

 

hi
ive done as above to find mine is the AC version
but im unsure wot cc my chinesse quad does this matter when buying a CDI?

thanx
simon

 

Simon,

Are you sure that the CDI is AC powered? No questions or hesitations that we need to revisit in your test results?

If your CDI looks exactly like the CDI pictured in your post, and your sure that your CDI is AC powered, then just buy one. It will work. But make sure the vendor you go to knows the difference. Ask them whether the CDI is AC or DC powered. If they hesitate, or tell you there is no difference, ot they tell you their's is universal, etc, then shop elsewhere. A lot of chinese import parts vendors don't have a clue as to what they are selling. They rely on the customer being just as uninformed, and so they get away with it.

We have a new sponser in this forum subgroup (Mainstreet). Why not give them a try? Gary's posts here thus far have been knowledgable and very helpful .

 

Hi lynn
ill double double check monday as the quad is at work but following your testing post it was reading 50 on the AC 200 setting
ive messaged a couple of evilbay sellers and they have said am i sure there
is different ones one has come back with a yes they sell a AC version but not on evilbay and would have to ring their sales line
which makes me think they gonna want mega ££ for it

Si

 

When measuring the ignition power while cranking the engine (CDI disconnected), 50 volts AC on the 200 volts AC setting is convincing evidence that the CDI is AC powered.

I guess I should have asked earlier : Why are you looking to buy a CDI? Are you having no spark problems? Have you measured the trigger signal AC voltage? The AC voltage to the ignition coil primary? Has the kill switch wiring been eliminated as the problem?

Your talking about ££ to buy a new CDI. Here in the USA chinese CDI's are really cheap (much less then $20 USD including shipping), so sometimes it pays to just "buy it and try it". But if the CDI is really expensive it makes sense to do a little more measuring first .

 

hi lynn
have bypassed the kill switch so thats out of the loop

yes no spark at all have changed plug,CDI and got the complete lead,cap
but still not even a little spark

what other tests can be done?
Simon

 

Whenever someone says they "bypassed the kill switch" it raises a red flag. The term "bypass" suggests that you added something (like a wire maybe), and that would be wrong...

To disable a kill switch you unplug it. Shorting the two wires of any kill switch together *kills* the spark. I'm just making sure you eliminated the kill switch(es) correctly...

So you measured the AC Ignition power going to the CDI. Did you measure the trigger voltage too?

Did you measure the output of the CDI going to the ignition coil?

I'm assuming you already have the procedure for doing this since you have the AC ignition power test done already. If you don't have it I can type it out again...