Skoda Fabia Ignition coil

Skoda Fabia 1.2L 2005 cutting out and non start until fuse replaced.

A reasonably simple problem, but quite nice as a casefile, as it really illustrates the potential for failure of the component.

When I came to this vehicle, it was a non start and the fuse for the ignition coils had blown.  I replaced the fuse and started the car.

The car started just fine, it ran a little lumpy and the fuse blew again after a short time running.

So I set up the scope using just a current clamp.  I managed to get the clamp on a section of harness right at the ignition coil wiring on the top of the engine.

Ignition coil current ramps
Skoda 1.2L 3 cylinder ignition coil ramps

As can be seen, this capture quickly showed a problem in the ignition coil pattern.  So I went on and disconnected a coil to trace which one was the real problem.  I started with cylinder 3.

Ignition coil current ramps with disconnect
I disconnected No.3 coil

I struck lucky first time!  As you can plainly see, the current ramp pattern instantly changed and the car continued to run until I switched it off.

We’ll have a look in more detail.

Ignition coil current ramps details
Coil current ramps in detail

You can see here that the coil for cylinder 3 is pretty close to a ‘dead short’, but 1 and 2 are not even.

I left this car with the garage, with the recommendation of a set of coils.  I don’t know whether they were all changed or just the one, but my work was done.