Ask the Editors: New Components but Still No Spark

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Jumping gigawatts!

Dear ATVC: I have a 2010 110cc Tao Tao ATV with a recently replaced CDI box and ignition coil. It turns over but will not fire up. I have taken the plug out and have no spark. I am lost I don’t know what else to replace. Any help is greatly appreciated. Deyles01

Well the good news is that you may not have to replace anything else. With a new coil and CDI and a machine that turns over but is not producing spark, it sounds to us like you’ve simply got to isolate exactly where you’re losing electrical contact. You go about accomplishing this task by picking up an electrical multimeter and placing your contacts at various points of the ATV’s circuitry.

The most common culprit in these situations is a faulty kill switch. A simple means to test this would be to disconnect the kill switch wire from the CDI and try firing it up. If it makes spark (or better still, starts) then you know it’s one of the machine’s kill switches.

Most Chinese ATVs have many of these unfortunately- A handlebar kill switch, ignition switch, tether cord kill switch and often a remote control module which shuts down the machine via remote.

You can check these setting your multimeter to measure ohms. Measure the resistance by placing one of your leads on the detached kill switch wire and the other to ground. It should read zero ohms.

Unplug the remaining switches at the wiring harness one at a time and perform this test on each individually. Should you happen upon one where the resistance jumps to open, you’ve found the faulty switch.

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