[surf2727]

So I've got a '10 335i w/ 49k miles on it and have been getting a consistent misfire in cylinder 1 and notice rougher startups than in the past. I changed all spark plugs earlier this year and also swapped coils to check if it was them that were bad...nothing. I even replaced the coils. Anyways, I know I could be wrong, but I've attributed all of this to carbon buildup within the manifold (or bad injector) and was curious if (and how) people brought their cars in to the dealerships to get them to perform walnut blasting? If under warranty, was it free? What did you say when you brought it in and how did they diagnose it? Any other feedback would be great as I will likely schedule an appointment soon. Oh, and my car is currently covered by BMW's maintenance plan for just one more month, but my warranty is valid for another couple of years. Thanks for the input!

Lastly, are injectors covered under the maintenance plan or warranty?

[feconi]

Originally Posted by surf2727

my warranty is valid for another couple of years.

Is this the CPO warranty, or do you still have a month of the original factory warranty coverage?

If you still have the original factory warranty I would take the car in before it runs out and complain of misfires. If the plugs, coils, and injectors are good, the next step in their diagnostic process will be to check for carbon buildup.

My experience on this issue: I've had a persistent cylinder 5 misfire and have been to the dealer 3 times in the past month for it. They've replaced an injector, plug, and coil on #5 under my CPO warranty.

When those parts didn't solve the problem I brought the car back again complaining of misfires (with the fault code stored in the DME, of course). The dealer pulled the intake and blamed carbon deposits on the valves as the root cause. They offered me walnut blasting, but said it would NOT be covered under CPO and would cost me $1k.

After a lot of discussion with the SA and manager they refused to pay for the walnut blasting, so I was charged a diagnostic fee of $160. I'm getting the service done today at an indy shop for less than half the cost that BMW quoted me.

[blacknbean]

^^ wow thats bad dealer service. i had a reocurring vanos solenoid issue where they cleaned the first time, codes came back and they finally replaced. while replacing they checked for carbon and walnut blasted it to make sure all issues were resolved. all this was done right before my CPO ended.

ive gone to 4 diff dealers with my car and ive noticed they are all hit or miss. no standards with what they do or dont do. so when one fails, just goto another

[surf2727]

Thanks for the feedback! I bought the car as a CPO and I believe the factory warranty expires on 12/22/13 or before 50k miles (I'm at 49.5k miles as of today!)and my CPO kicks in until 12/22/15.

Originally Posted by feconi

If you still have the original factory warranty I would take the car in before it runs out and complain of misfires. If the plugs, coils, and injectors are good, the next step in their diagnostic process will be to check for carbon buildup.

My experience on this issue: I've had a persistent cylinder 5 misfire and have been to the dealer 3 times in the past month for it. They've replaced an injector, plug, and coil on #5 under my CPO warranty.

Should I go in telling them I checked the codes and there have been misfires as well as the occasional rough startup? Also, I'm surprised they replaced the injectors, plug, & coil for free!

And, for peace of mind, I'm guessing I should remove all of my mods prior to my appointment? After uninstalling everything, would it help to try and throw a misfire code again before bringing it in? Anyone got any recommendations on how to do this?

Thanks again for all of the helpful feedback!

[johngrossi]

From my experience within the automotive world and knowing dealer technicians I wouldn't say you checked the codes. They may think you have taken things apart yourself and will look for a reason to not cover your issue under warranty.

Techs get paid a fraction of book time to what they would get paid to do a non warranty repair. Nobody likes to do warranty work because of that.

Also what I have seen is a lot of less experienced techs being given warranty work so the journeymen techs can book more time with other jobs

As mentioned earlier try more than one dealership if that is an option.

Just my 2 cents

Best of luck to you!

[Javier]

i am also getting rough idle and the occasional stumbling at a traffic light, but i haven't been able to get a misfire code (happened twice in the past) when i take it into the dealership. They say they don't see a problem, but i notice it while driving some times.
I'm pretty sure its carbon buildup and would like to have them do it before my warranty is up next month (also 2010).

any ideas on how to trigger a misfire code?

[Boost4me]

With me, I was getting misfires when I was accelerating to speed on freeway on ramps. It triggered my SES light on, I brought my car in to the dealer since I was still covered under CPO. Dealer swapped coils & plugs around and could not find the issue, after about the 3rd try, they decided to take a look at the intake valves & found really bad carbon build up. They did a walnut blast & told me it was covered under CPO warranty & that was the end of that. Car has been running great since

[mikolo-n54]

payed 700 at the dealer for an out of warranty car. It was convenient and close but I know I could have done it for much less at ltmw just to far and inconvenient.