In order to get power to the plug, there needs to be a full cicuit. Power goes to the plug via the extension lead, and returns back to the driver via the plug body, normally to the outer case of the driver connector. With the single lead extensions, this power must be returned via the plug to the crankcase, and to the bracket that holds the nib that you connect the driver to - that bracked MUST be mounted in direct metal to metal contact with the engine, or you will not have a complete circuit, and will not light the plug. Where (and to what) do you have the end of your plug extension which is NOT connected to the plug, mounted to?

- Tim