When to replace ignition coils?

[Stephen120173]

Wondering when to replace the coils on my 2008 Z4 2.0 with 55k miles.

Yes - I know it’s the 4 cylinder but the lightness up front really changes the turn-in and response on twisty roads...

Warm idle is a little lumpy and as I’ve had the fuel system cleaned I’m wondering if this would likely be the coils?

Anyone done swapped out the coils for similar reasons?

 

[Lance]

My opinion is it’s unlikely to be the coils. A failed coil is very very noticeable.

Personally I wouldn’t change the coils until they fail. Even then I’d only change each failed one and not them all as a set.

If you’re worried about them, get one and keep it as a spare in the boot, along with tools to change it. If your set up is anything like a 2.5, then it’s 2 minutes and a very easy swap.

I had a coil go about 3 years ago, no more have gone since.

 

[skelters]

What fuel are you using?

When we're the plugs changed?

When was it serviced?

Which plugs are in it?

 

[Jl-c]

If you had 25% of your cylinders not functioning you would not have "little lumpy" , it would be horrible to drive

 

[Smartbear]

Wondering when to replace the coils on my 2008 Z4 2.0 with 55k miles.

Yes - I know it’s the 4 cylinder but the lightness up front really changes the turn-in and response on twisty roads...

Warm idle is a little lumpy and as I’ve had the fuel system cleaned I’m wondering if this would likely be the coils?

Anyone done swapped out the coils for similar reasons?

A failing coil would normally be logged as a misfire on a specific cylinder, what’s your code reader saying? :?
Rob

 

[Stephen120173]

Thanks guys. I run Shell V Power 99, had a recent terraclean, the plugs were done 10k miles and 1 year ago at an Inspection 2 service but I have no idea which plugs they are.

I was thinking that a coil performance would degrade before it failed and if they don’t degrade at the same rate then that would lead to different spark strengths owing to the different coil impedances.

Bigger issues to focus on Janie due to an MoT failure.

Separate post for that...

 

[Smartbear]

Thanks guys. I run Shell V Power 99, had a recent terraclean, the plugs were done 10k miles and 1 year ago at an Inspection 2 service but I have no idea which plugs they are.

I was thinking that a coil performance would degrade before it failed and if they don’t degrade at the same rate then that would lead to different spark strengths owing to the different coil impedances.

Bigger issues to focus on Janie due to an MoT failure.

Separate post for that...

I’d say coils either work or they don’t work properly, I’ve never routine changed them.
Rob

 

[tug]

The N46 is notorious for having a "rough idle" but this can be sorted by having the valvetronic adaptations wiped using ista software.

Cheers, tug