[thkfast]

I just bought this 2012 335is 1 week ago - it has 51,000 miles and was a 2 owner/lease vehicle. Non-CPO and NO WARRANTY at all. It's all stock.

BMW maintenance records show new plugs installed at 45,000 miles.

No major maintenance done other than yearly oil changes, brake fluid, wipers, you know.

My previous cars were '07 and '10 335i, so I know how they should run. I would describe the power as "pulls harder each time it shifts!" This 335is is supposed to have that 7 seconds of OVERBOOST and 370 ft lbs of torque...well, I'm not feeling it. Don't get me wrong, the car runs okay under full throttle, but doesn't pin you back in the seat like my previous 335i would. The car shakes with a rough idle sometimes at start up and when sitting at a red light. It has stalled ONCE. I've gotten the Service Engine Soon light three times which re-set themselves, except for today when it finally stayed on. We hooked up a scan tool and it showed "CYLINDER 3 MISFIRE." We cleared the code.

From reading the other misfire / rough idle / shaking posts, I understand the troubleshooting order is PLUGS, COILS, then INJECTORS. I'm scheduled for a Walnut Blast next week at my local BMW dealership ($644) and I'm wondering if I should have them do anything else while they have it apart? I'm wondering are the plugs, coils, injectors all right there when they're blasting the valves clean?

Goal: I want the engine to smooth out, stop setting the SES light and perform better.

Advise? Thanks!

[Culichor]

Check your mail box.

[msjt]

Rough idle at start-up is usually a sign of leaking injectors.

[Holshot]

Just a heads up... Try looking for for an Indy shop as you'll find that they do the walnut blasting service at half the cost of the stealership. Check out the regional forums below as to what others have paid and where they found a good Indy service shop and save yourself a lot of cash that can be put forward to other things that may need attention. Just some food for thought...

P.S. To try and diagnose the cylinder 3 misfire issue, try swapping out one of the other coils and see if that same cylinder come up with the misfire or if it follows to the cylinder you swap with. Also, pull the plug in the issue cylinder and see if it's wet with fuel, that may help figure out if you have a leaky injector.

[thkfast]

Thanks guys. I'm going to have the walnut blasting done, then see if I'm still getting a SES light or misfire and go from there.

Some people have suggested I try to "guilt" the dealership I bought the car from to pay for the walnut blasting as it's a KNOWN ISSUE with N54 cars with miles.

[mike@x-ph.com]

First dont pay $644 for walnut blasting !!!
Get someone local to do it for $200

Check the code and see where you are getting the misfire then swap that injector and move to another cylinder, see if misfire follows.

[thkfast]

Originally Posted by mike@x-ph.com

First dont pay $644 for walnut blasting !!!
Get someone local to do it for $200

Check the code and see where you are getting the misfire then swap that injector and move to another cylinder, see if misfire follows.

Thanks Mike! I'm cheap...so I'd love to have an Indy shop do it for $200. The local "Indy" BMW/Audi/Mini guy wanted $600 to clean the intake valves using some super toxic chemical that soaks overnight and dissolves the carbon. He was also unwilling to let me see the valves before/after his work! That's when I checked with the local BMW service advisor and they said $644 and would let me see the valves before/after. There's not much for reputable Indy shops around Cedar Rapids IA - I checked the regional threads also.

I'm open to all suggestions. With 51,000 miles, I think I'm overdue for walnut blasting!

[335e92]

Go to you local dealer and ask them if your injectors are under warranty?
I got all 6 of my injectors replaced for free. My car had 84K on it.
Hope it works out for you. Nothing worse than having a nice car that you can't enjoy.

BMW service is awesome!

[thkfast]

Originally Posted by 335e92

Go to you local dealer and ask them if your injectors are under warranty?
I got all 6 of my injectors replaced for free. My car had 84K on it.
Hope it works out for you. Nothing worse than having a nice car that you can't enjoy.

BMW service is awesome!

Just like that? Not a recall or anything, just ask them if my injectors are under warranty? Should I imply there's something wrong with the injectors given the misfire code?

[335e92]

Originally Posted by thkfast

Just like that? Not a recall or anything, just ask them if my injectors are under warranty? Should I imply there's something wrong with the injectors given the misfire code?

sorry!

YES! Imply there's something wrong with the injectors and misfire.
There is a manufacturer warranty.

[335e92]

Originally Posted by 335e92

sorry!

YES! Imply there's something wrong with the injectors and misfire.
There is a manufacturer warranty.

I was going in to buy an injector at the dealer and the service parts guy told me that it might be covered under some warranty. I dropped my car off and 3 days later all 6 injectors replaced with new spark plugs.

[thkfast]

I will give it a try!

I'll post a complete update on results of walnut blasting as well.

Thank you.

[mike@x-ph.com]

Originally Posted by thkfast

Thanks Mike! I'm cheap...so I'd love to have an Indy shop do it for $200. The local "Indy" BMW/Audi/Mini guy wanted $600 to clean the intake valves using some super toxic chemical that soaks overnight and dissolves the carbon. He was also unwilling to let me see the valves before/after his work! That's when I checked with the local BMW service advisor and they said $644 and would let me see the valves before/after. There's not much for reputable Indy shops around Cedar Rapids IA - I checked the regional threads also.

I'm open to all suggestions. With 51,000 miles, I think I'm overdue for walnut blasting!

I meant someone local on the forums. i got mine done for $150

[Jeff@TopGearSolutions]

Originally Posted by thkfast

Thanks Mike! I'm cheap...so I'd love to have an Indy shop do it for $200. The local "Indy" BMW/Audi/Mini guy wanted $600 to clean the intake valves using some super toxic chemical that soaks overnight and dissolves the carbon. He was also unwilling to let me see the valves before/after his work! That's when I checked with the local BMW service advisor and they said $644 and would let me see the valves before/after. There's not much for reputable Indy shops around Cedar Rapids IA - I checked the regional threads also.

I'm open to all suggestions. With 51,000 miles, I think I'm overdue for walnut blasting!

Anyone that functions like this should not be in business and is either not doing honest work and/or not confident in the results of their work.

Talk to guys in your regional section and see if they want to chip in for the walnut blasting tools and such and run your own walnut blasting weekend group buy

[thkfast]

UPDATE: Today is the big day - I take the 335is in for walnut blast and hopefully the BMW tech recognizes what's going on with the car. In addition to SES light and codes for misfires, on cold start up the engine races to 1,500 rpms, the exhaust note is much louder than normal and I've noticed black specks of soot on my rear bumper which I assume is due to a rich fuel mixture. AND yesterday for the first time, the engine started bucking and sputtering and coughing and shaking for about the first 1 mile....then just came out of it like nothing happened.

99% of the time, the car runs fine, just the occasional short term rough idle and now the crazy bucking and sputtering that lasted about 4 minutes.

Anyway, the BMW SA is going to let me take before and after photos of the intake valves. If it's not too expensive, while they have everything apart, I'd like to have them check the spark plugs, the ignition coils and inspect the fuel injectors. I'll let you know what comes of my service visit.

[musc]

As far as feeling the overboost, you won't. With the DCT gearing the car won't feel quite as torquey as an AT/MT. The engine revving up and the louder exhaust is normal at start up as well. The car is in open loop fueling the exhaust flap will open. You will hear it shut and the rpms settle down when the car goes back to normal closed loop.

[thkfast]

TODAY: BMW dealership pulled everything off, let me take a look at the intake valves - not too bad actually. I will still go ahead and have them walnut blasted ($650). The Tech did a diagnostic test ($125) and it showed the problem to be at least 2 bad injectors - BMW recommending replacing all 6 for ($2,417), but the Tech agrees they should be warrantied because they shouldn't have failed after 3 years and 51,000 miles - his opinion doesn't count...

Now I'm waiting for the Service Advisor to check with BMW and see if they'll replace the injectors under warranty as was suggested by 335e92. Stand by.

Photos: It looks like they get worse as you go back towards the firewall.

[musc]

I wouldn't spend a dime on injectors without replacing plugs and/or coils first. I am sure the dealer would love for you to pay for 6 new injectors. If they are going to cover them under warranty then sure, I'd let them do it.

Even if the plugs are fairly new they can still be bad. If you are getting a misfire on cylinder 3, check the plug. If it visually looks fine, swap the cylinder 3 coil and see if the misfire moves. While injectors can be cause of a misfire, more often than not it is related to the coils/plugs.

[Jeff@TopGearSolutions]

Originally Posted by musc

I wouldn't spend a dime on injectors without replacing plugs and/or coils first. I am sure the dealer would love for you to pay for 6 new injectors. If they are going to cover them under warranty then sure, I'd let them do it.

Even if the plugs are fairly new they can still be bad. If you are getting a misfire on cylinder 3, check the plug. If it visually looks fine, swap the cylinder 3 coil and see if the misfire moves. While injectors can be cause of a misfire, more often than not it is related to the coils/plugs.

+1

Also if they don't warranty the injectors; I'd pay their diagnostic fee, source the injectors yourself and have an independent shop do the work for a fraction of the cost. You'll also save on parts sourcing the injectors yourself.

As much as the spark plugs may be new, a leaky injector could have fouled it so they need to be checked.

The gap is also important too so that should be checked as well.

[thkfast]

Originally Posted by Jeff@TopGearSolutions

+1

Also if they don't warranty the injectors; I'd pay their diagnostic fee, source the injectors yourself and have an independent shop do the work for a fraction of the cost. You'll also save on parts sourcing the injectors yourself.

As much as the spark plugs may be new, a leaky injector could have fouled it so they need to be checked.

The gap is also important too so that should be checked as well.

------------------

Gotcha! I apologize, I'm juggling two threads on this topic so hopefully I'll wrap this up soon. I did pay the $125 diagnostic fee and they say it's the injectors specifically, no problems flagged with the plugs or coils. The dealership and BMW corporate both denied covering replacement of the injectors so I'll likely farm it out to an indy shop. Sounds like I probably ought to have them throw in some new plugs while they're at it. I will finish this thread off with an update within a week. Thanks all.