35iS Ignition Problem

[mpc007]

Yesterday picked up the successor to my Toledoblue E85 3.0i S, its a lovely looking E89 35iS in Melbourne Red, pic below:

https://imgur.com/a/YHzJxko

However, on my second drive the car displayed following:

1. E89 35iS DCT
2. 2010
3. Melbourne Red
4. Kansas Black

5. Issues experienced, notes & status e.g.

5a. Car seemed to have serious trouble accelerating, almost shutting of at low speeds. Quite some vibration and strange noises in the car which seemed to come from the drivetrain. My own thoughts immediately were either one or multiple cylinders failing / misfiring, a DCT issue, a big vacuum leak, or something fuel related (injectors or pumps)
5b. Current status - Unresolved
5c. Car has a 6 month warranty for drivetrain, transmission, and roof. Didn't contact them yet, wanted to check here first.
5d. Mileage = 118k kms (73k miles)
5d. Car is stock, no ECU maps on it AFAIK
5d. Used my OBD code reader on the car and the DME department had two fault codes stored:
- 2DED > 'Power management, close d-circuit current violation'
- 29D0 > 'Combustion misfires, cylinder 4'

Luckily, the car was delivered to me with a large service done just last week, during which also the spark plugs were changed. So I'm thinking it may be ignition related, maybe a bad coil? Look forward to reading your replies.

UPDATE: the issue and CEL are gone after restarting the car, but they can be triggered by going hard on the throttle.

[B21]

Your combustion misfire is almost certainly caused by a coil failing…if you have fresh plug’s correctly gapped..

The cel light going out and all well till you provoke is typical of that issue..

Need 6 fresh coils..

[mpc007]

Your combustion misfire is almost certainly caused by a coil failing…if you have fresh plug’s correctly gapped..

The cel light going out and all well till you provoke is typical of that issue..

Need 6 fresh coils..

Thanks for your reply. Wouldnt it suffice to have just the number 4 replaced?

[flybobbie]

In my 23i car, no.4 cylinder plug hole, cam cover had a oil leak, caused unstable idle on start until the alternator kicked in to 14.3 volts, then ran smooth.
Might have similar, ask yourself why car was sold on.
I fixed by fitting new cam cover, i assume it bowed.

[B21]

Your combustion misfire is almost certainly caused by a coil failing…if you have fresh plug’s correctly gapped..

The cel light going out and all well till you provoke is typical of that issue..

Need 6 fresh coils..

Thanks for your reply. Wouldnt it suffice to have just the number 4 replaced?

Cause once one goes they all go,..it’s a disposable item like plugs, filters, oil…

N54 engines eat plugs n coils

Anything over 60k miles on the original coils is a bonus…

Use Eldor, NGK or Bosch in that order

[mpc007]

Your combustion misfire is almost certainly caused by a coil failing…if you have fresh plug’s correctly gapped..

The cel light going out and all well till you provoke is typical of that issue..

Need 6 fresh coils..

Thanks for your reply. Wouldnt it suffice to have just the number 4 replaced?

Cause once one goes they all go,..it’s a disposable item like plugs, filters, oil…

N54 engines eat plugs n coils

Anything over 60k miles on the original coils is a bonus…

Use Eldor, NGK or Bosch in that order

Good to know, thanks mate. Would you go as far as to say that because the estimated lifespan of the coils is 60k therefore its best to just preventively swap them out at 60k / 120k /180k/ etc?

I'm still learning a lot about this N54 engine. It seems to have quite different 'challenges' than the good 'ol M54 which I had in different cars in different variations.

[B21]

Thanks for your reply. Wouldnt it suffice to have just the number 4 replaced?

Cause once one goes they all go,..it’s a disposable item like plugs, filters, oil…

N54 engines eat plugs n coils

Anything over 60k miles on the original coils is a bonus…

Use Eldor, NGK or Bosch in that order

Good to know, thanks mate. Would you go as far as to say that because the estimated lifespan of the coils is 60k therefore its best to just preventively swap them out at 60k / 120k /180k/ etc?

I'm still learning a lot about this N54 engine. It seems to have quite different 'challenges' than the good 'ol M54 which I had in different cars in different variations.

I’d replace the set when the first one misfires..the number of cycles, the amount of heat, age, type of use all affect predicted life..

You could preemptively swap them out but that would be less economical..

If you are going to re-map the engine then it’s good to do preemptively..

Keep your cash for your water pump, HPFP, turbos, adaptive dampers, cam cover gasket etc…

[mpc007]

Cause once one goes they all go,..it’s a disposable item like plugs, filters, oil…

N54 engines eat plugs n coils

Anything over 60k miles on the original coils is a bonus…

Use Eldor, NGK or Bosch in that order

Good to know, thanks mate. Would you go as far as to say that because the estimated lifespan of the coils is 60k therefore its best to just preventively swap them out at 60k / 120k /180k/ etc?

I'm still learning a lot about this N54 engine. It seems to have quite different 'challenges' than the good 'ol M54 which I had in different cars in different variations.

I’d replace the set when the first one misfires..the number of cycles, the amount of heat, age, type of use all affect predicted life..

You could preemptively swap them out but that would be less economical..

If you are going to re-map the engine then it’s good to do preemptively..

Keep your cash for your water pump, HPFP, turbos, adaptive dampers, cam cover gasket etc…

Thanks, that's good advice. Just sent the shop that sold me the car a message with the problem description and the codes (since i got a 6 month warranty on drivetrain, dct, and roof), have to see what they'll bring forward.

Currently got no plans to do a remap. The car is quite a step up for me performance wise, coming from an 04 E85 3.0 past years and having an 08 Audi TTS as intermediate car over past months.

The turbos were done by the previous owner a few years ago when it had 46k miles (now at 73k) so I hope they'll hold on for a few years But I see what you mean, not looking forward to a HPFP or damper issue

[mpc007]

Went by the repair shop today in order to have it looked at (under warranty) and they replaced 6 plugs and 6 coils, so I'm quite happy they didn't just try to locate failing one. Did a quick test run on their advice and couldn't reproduce the same check engine light / running on 5 pots issue again. Didn't cost me a penny so all good so far.

However on the way back home I did notice another smaller issue which I earlier presumed to be related but after the repair job this is still present. I'm not 100% sure its also ignition related because it doesn't throw an OBD code or check light. It's best described as small shocks going through the car and drivetrain when pulling hard in sport mode (in sport+ i can't get it since it only happens at lower revs). It was a bit wet on the road so thought maybe a traction issue but DSC is not lighting up and its also there on perfect straight and good quality roads. Then I thought maybe the DKG transmission slipping in gear but then I guess it should have shown the infamous 'cog of death' light and certainly some code. I learned injectors have been replaced under previous owner less than 2 years ago. Only thing that comes to mind is a fuel supply related issue / fuel knocking - how picky is the 35iS with lower quality fuel?

Over past days I've been running RON 95 (with the standard E10 mix we have on mainland Europe) and I also heard the N54 can be a bit of a nitpicker when it isn't served RON 98 (E5)..

[Argyll Andy]

I’m a bit unsure how to interpret

“ It's best described as small shocks going through the car and drivetrain when pulling hard in sport mode (in sport+ i ”

But if it’s what I think you’re saying are you sure it’s not just the lsd/traction control electronic wizardry trying to keep you in a straight line. I remember I had an unfamiliar driviing experience when I first got my 35iS. Asked a trusted mechanic to come out with me and check if everything was ok. His response was “you’re driving it that f***ing hard it’s the cars electronics working in the background doing their job and trying to keep you out of the hedges”

[B21]

N54 has relatively sophisticated anti knock control…so highly unlikely that you are hearing / feeling knock…

It should be ok on 95 Ron fuel…assuming it’s not been re-mapped for 98-101 fuel..

Your description sounds a bit vague but as Andy says could be DSC trying to keep you alive..

[mpc007]

Thanks guys, i'll try to maybe do a video on it when I got the chance.

Afaik it has not been remapped but i will try to burn a tank of ron 98 in order to make sure its not the issue.

If its a dsc or traction related issue, shouldnt dsc light come up when its intervening? It would make sense that issue is not noticable in sport plus when TC is off, but i will test that too. Thought the E89 never had a proper LSD?

I have to admit im on crap tires currently, prev owner fitted Kumhos, think RFTs. But there is too much life left on them to just ditch m already

[Pondrew]

I have to admit im on crap tires currently, prev owner fitted Kumhos

Nothing wrong with Kumhos. I had a remapped B58 engined BMW with more power and torque than a 35is and it was absolutely fine on Kumho Ecstas.

[Argyll Andy]

Thanks guys, i'll try to maybe do a video on it when I got the chance.

Afaik it has not been remapped but i will try to burn a tank of ron 98 in order to make sure its not the issue.

If its a dsc or traction related issue, shouldnt dsc light come up when its intervening? It would make sense that issue is not noticable in sport plus when TC is off, but i will test that too. Thought the E89 never had a proper LSD?

I have to admit im on crap tires currently, prev owner fitted Kumhos, think RFTs. But there is too much life left on them to just ditch m already

No, mine didn’t through traction light when doing this.

You’re correct, no proper LSD but an electronic version “mimicking” one and that’s possibly the feeling you’re getting, it kicking in and out.

Don’t remember the mode I was in making a difference

Nothing wrong with Khumos, used many times including on my E90 currently, but only normal tyres, never used their run flats

My unmapped 35iS almost always ran on 95 Ron as regularly couldn’t get higher octane locally HTH

[B21]

Thanks guys, i'll try to maybe do a video on it when I got the chance.

Afaik it has not been remapped but i will try to burn a tank of ron 98 in order to make sure its not the issue.

If its a dsc or traction related issue, shouldnt dsc light come up when its intervening? It would make sense that issue is not noticable in sport plus when TC is off, but i will test that too. Thought the E89 never had a proper LSD?

I have to admit im on crap tires currently, prev owner fitted Kumhos, think RFTs. But there is too much life left on them to just ditch m already

As Andy says the DSC light doesn’t often come on unless it’s trying really hard to control things…the e-diff is a faux LSD..if the tyres are letting go then you will get a bit of engine shut down coming in intermittently…

Not sure about your tyres but you can easily unseat the tyres if you boot it hard, especially in bumpy corners..or damp roads..

Crap suspension is an issue..if it’s shagged then you can axle tramp and again unseat the tyres…