Bad Coil?

[CosmoTG]

Can one side of a coil go weak or bad? I am trying to eliminate possible causes for my front plug fouling...Cos

[dttheliman]

Cos, flip the HT leads over at the coil , go for a ride , is your rear plug now fouled, or still the front. Change HT leads next - repeat . imho coils especially dual fire either work or dont.

[Fe Head]

Are you running a dual fire coil system or single fire?

The secondary windings (high tension side) is the same for both spark plugs and theoretically the voltage -spark strength should be exactly the same.
One end of the secondary is connected to each of the two high tension towers in a dual fire system.

You can check this by placing a Phillips scewdriver in each plug boot and hold them by the plastic handles and set these near to the engine will cranking over the engine and compare the colour and snap of each spark. They should be exactly the same.

To check for a weak high tension side of the coil use an Ohm meter and probe the coil from one high tension tower to the outside insulation of the coil. It should be about 30K if not then the secondary is shorting out. but this will have an effect on both plugs in a dual fire. In single fire it will be unigue to that high tension tower.

Cheers;

[SpringerSam]

I agree with Fe Head...my experience is that a spark does not weaken unless water or moisture is involved (alternate paths of electricity). I think a coil that is defective is either shorted or open and rarely in between...

Sam

[MDT]

I've had them crack, then they act up when they get wet, or hot or whatever.