[nicktyler]

Hi

I got the EML and reduced power/lumpy engine today and took it straight down the garage. Unsurprisingly it showed coils and plugs code.

My question is should they all be replaced or just the bits that have failed? Also would any of it be on warranty as I only bought it 3 weeks ago from a indy dealer

I have a 2007 335i with 40k on it and looking at the service history it looks like they hve not been replaced before.

Thanks

[m1bjr]

Coils AND plugs?

Highly unlikely.

I would change the plugs anyhow as a precaution, I did exactly the same at about 50k.
They were in good shape tbh, slight erosion of the tips that was all.
Make sure you fit the GENUINE articles, they are not very common but have TWO electrodes.
A set should run to about £100 or so and a half hour labour.

Coilpacks are plug and play, a 20min job to change one out. I would NOT bother doing the set.
Most likely you can read the code to tell you which cylinder is in error, and just replace that coil.
I did one last week as it happens

[makkan00]

Originally Posted by m1bjr

Coils AND plugs?

Highly unlikely.

I would change the plugs anyhow as a precaution, I did exactly the same at about 50k.
They were in good shape tbh, slight erosion of the tips that was all.
Make sure you fit the GENUINE articles, they are not very common but have TWO electrodes.
A set should run to about £100 or so and a half hour labour.

Coilpacks are plug and play, a 20min job to change one out. I would NOT bother doing the set.
Most likely you can read the code to tell you which cylinder is in error, and just replace that coil.
I did one last week as it happens

+1, very thorough reply.

Once you get the code (lets says Cylinder 1 coil pack error), change it with other cylinder (lets say you moved it to Cylinder 3).
Now restart the car and re-run the diagnostics, and if you get the error for Cylinder 3, it will confirm your tests.

All the best and warranty should cover this (as these are not wear and tear items, however plugs are debateable).

[m1bjr]

Originally Posted by makkan00

+1, very thorough reply.

Once you get the code (lets says Cylinder 1 coil pack error), change it with other cylinder (lets say you moved it to Cylinder 3).
Now restart the car and re-run the diagnostics, and if you get the error for Cylinder 3, it will confirm your tests.

All the best and warranty should cover this (as these are not wear and tear items, however plugs are debateable).

Its not always so clear cut however.

My Coil had an intermittant and 'slight' fault.

There has been a slight hesitation or 'miss' on hard acceleraton for a long while.
Felt like throttle closure or slight DSC intervention (hint of wheel slip), and looked like that in the datalogs too.
No codes were ever logged...
Until recently when it dropped onto five cylinders (shakes like a wet dog and no power).
Then bingo you get a cascade of usable error codes, in my case 29CF (misfire on 3)
and 9DC as the fuel gets turned off.

The running on five cyls thing seems to be (and I await confirmation) deliberate by the DME.
A misfire can exist if minor for a long time, as I know.
But once it worsens I think the error gets generated and the injector switched off
Presume so you dont throw unburned fuel into the cats.
And this is where the huge 'running on five cyls' comes in.
If you stop and restart immediately, you may find it runs on all six again but the misfire remains obviously.

You may well swap this coil (I did as you suggested) and find it works again for a very long time.
It was obvious on removal though the second time, lots of tracking marks (arcing) and a smell of burnt insulation.
Annoying!

[nicktyler]

Hi

Thanks for the info. I am just going to let them change all the plugs and coils. Looking in the service book they have never been done and the car has done 40k so the plugs are probably due for a change anyway and then all the coils will hopefully last for a while too. I'll keep the current ones in case of emergency. Might give the warranty company a ring but not holding out much hope of them paying anything.

Also it is £450 all in for genuine parts which seems like a reasonable price?

[greatbm]

Originally Posted by nicktyler

Hi

Thanks for the info. I am just going to let them change all the plugs and coils. Looking in the service book they have never been done and the car has done 40k so the plugs are probably due for a change anyway and then all the coils will hopefully last for a while too. I'll keep the current ones in case of emergency. Might give the warranty company a ring but not holding out much hope of them paying anything.

Also it is £450 all in for genuine parts which seems like a reasonable price?

Got a miss fire on No3 cylinder just before xmas. Mondial under BMW extended warranty came to house and changed all 6 plugs and 6 coil packs. Technician said I was lucky that the coil packs had not failed earlier as they had been superseded some time ago. Original all black in colour and new all grey but still Bosch. All in all no charge great service and miss fire gone.

[nicktyler]

That is good that the extended warranty covered it. That is the value of a BMW warranty and the premium on an approved used car I suppose. I just have the warranty the car came with as it was from a dealer. They said they woud only pay for the coils that have failed and not for any plugs. They also wanted the failed parts to eb sent to them for inspection and moaned that I had taken it to a garage for diagnosis before telling them about it (apparently in the exclusions). When it happened I literally went straight to the garage and was there in 5 mins after the engine light came on.

I will give it a go but can tell it will be a massive ball ache and they will not pay out anyway probably quoting the diagnosis exclusion thing.

It is the best part of £500 but better to know it has been done and not waiting for the next one to go.

I was planning on getting the BMW used warranty for £40p/m as this should be better but now thinking the money might be better in a car fund account.

[nomile]

Just ran through all this. Maybe it will help someone:

Symptoms:
- For the last month, on really cold mornings, my car was hesitating at low RPM (1000-2200) when under load. Only happened a few times on the way to work, one particular corner (6th gear, not downshifting, just slowly pulling away, car would buck 3-5 times)
- Got worse in the last few days, but only low revs
- Removed engine cover, and had a ton of oil around the VANOS sensor
- At this point I did not have a CEL. I drove the car and stayed on through lots of hesitation (5-15 sec) until CEL came on.
- Used BavTech cable to see "misfire on cyl 3"
- Swapped coil with cyl 2, repeated - error moved to cyl 2
- new coil fixed it

I did blow out the oil in the VANOS sensor, so jury is still out whether that was part of the problem, but I blew it out the same time I swapped the coils around, so chances are that car is back to normal.

Good luck