[xabi]

Hi Guys,

I have a 2006 Scenic that today started to misfire and has a "check emmisions" light on. I suspected a coil so removed the electrical lead from each in turn, the first 3 cause the engine to stall, the fourth causes a noticeable roughness to the engine but it doesn't stall. Should removing the lead from a faulty coil show no change in idle? Or is it possible that it's giving a spEk but not a great spark?

Thanks

Xabi

 

[bobbydog]

Coils are often wired in pairs.

I've found the quickest way is to have a working spare handy and change each one in turn, it only takes a few seconds.

If one fails the rest will surely follow so its best to buy a complete set.

 

[Guest]

Hi Guys,

I have a 2006 Scenic that today started to misfire and has a "check emmisions" light on. I suspected a coil so removed the electrical lead from each in turn, the first 3 cause the engine to stall, the fourth causes a noticeable roughness to the engine but it doesn't stall. Should removing the lead from a faulty coil show no change in idle? Or is it possible that it's giving a spEk but not a great spark?

Thanks

Xabi

As already mentioned the coils are wired in pairs so when you unplug 1 coil you are disconnecting 2 of them.

One way to isolate a faulty coil is to disconnect the petrol injectors one at a time

 

[xabi]

Thanks all,

That explains it, after removing the lead from coil 4 I removed coil 1 and nothing changed. Are the pairs 1 & 4 and 2 & 3?

X

 

[Guest]

Yes 1 & 4 rise an fall together as do 2 & 3 as you can see from the photo of a 2.0 F4R

It's a wasted spark system as only one of the cylinders will be on it's compression stroke.

so if you unplug one of the coils from the good circuit you will disable those 2 coils and could be trying to run the engine on the 1 remaining good coil in the other circuit and hence the engine stalls.