[lordbmw]

Today I was driving and suddenly the engine started to run rough and vibrate.

I saw a "Service Engine Soon" light appear.

I was like, WTF?

Then I saw a snowflake warning in a triangle appear and I was freaking out. Apparently the snowflake warning can be ignored, lol.

Anyhow, I scanned for codes and found this:



It's says "29CD Misfirings, cylinder 1".

The other code "2FA3 Coding missing" is harmless and can be ignored.

WTF is wrong with my car?

Do I need a new engine?

[AM330i]

No, you don't need a new engine. Most likely plugs or coils or both. Also a possibility it needs an injector, but I would start with plugs and coils.

[WhiteBeard]

It's usually ignition coil that went bad. Easy to check: while engine is running remove the high-voltage wire from ignition coil. If it makes no difference at all - then you found bad ignition coil. If engine starts shaking - then plug that wire back and try next one, until you find the bad one:

In your case you already know it's cylinder 1 - so just try that one right away. Easy to fix - order a new ignition coil (I recommend ordering all 6 together as they are relatively cheap and you will have spare ones as chances are the rest of ignition coils may go bad in near future one by one).
Here's a price link to order them, $24 for 1 Delphi coil (which is cosndiered even better than original Bosch one): http://www.rockauto.com/en/catalog/b...le.com+URL+%2F

[BSM n54iS]

That snowflake appeared because your cylinder 1 got too cold and misfired as a result. Probably lost compression...possibly blew a hole in the cylinder wall allowing outside air in. You're fucked

[lordbmw]

Thanks guys, I'll try that ignition coil test soon.

[WhiteBeard]

Originally Posted by lordbmw

Thanks guys, I'll try that ignition coil test soon.

Just keep in mind, that if your ignition coil is acting bad on and off - I mean it is intermittent - then you may not find bad coil during test if coil is working good at that moment. You need to do a test when your engine has this problem present, don't shut it down, keep it running and diagnose a coil.
Alternately, just trust me on this - order 1 new Delphi coil and replace it in Cyl.1 and be done - it's safer and it's only $24. Good luck and keep us posted

[Eddien123]

Do I need a new engine?

[ctuna]

What is the voltage from that says 11.53 hope its not the
battery cause it would be low.

[lordbmw]

Originally Posted by ctuna

What is the voltage from that says 11.53 hope its not the
battery cause it would be low.

I just noticed that. I'm not sure what that is.
I had the battery replaced recently so it should be good.

[lordbmw]

Originally Posted by WhiteBeard

Just keep in mind, that if your ignition coil is acting bad on and off - I mean it is intermittent - then you may not find bad coil during test if coil is working good at that moment. You need to do a test when your engine has this problem present, don't shut it down, keep it running and diagnose a coil.
Alternately, just trust me on this - order 1 new Delphi coil and replace it in Cyl.1 and be done - it's safer and it's only $24. Good luck and keep us posted

The "Service Engine Soon" light did go away as I was driving.

Does that mean the problem is intermittent or would the warning light go away eventually even if the underlying problem is still present.

Also, can ignition coils go bad intermittently.

One interesting fact is that this was the coldest night for probably over 8 months. That's why I got the Snowflake warning light.

I wonder if the cold exasperated the problem. It must have since I never got the "Service Engine Soon" warning before. I bought the car in September of this year FYI.

[WhiteBeard]

Originally Posted by lordbmw

The "Service Engine Soon" light did go away as I was driving.

Does that mean the problem is intermittent or would the warning light go away eventually even if the underlying problem is still present.

Also, can ignition coils go bad intermittently.

One interesting fact is that this was the coldest night for probably over 8 months. That's why I got the Snowflake warning light.

I wonder if the cold exasperated the problem. It must have since I never got the "Service Engine Soon" warning before. I bought the car in September of this year FYI.

Absolutely, coils (winding) are heat sensitive and cold weather may have expanded range of temperatures they have to work in. From cold starts to the max temp they heat up during normal operation. I'm sure if coil started to go bad - it will repeat itself and you'll get same issue. You can wait until then to be sure if you want. Nothing really bad will happen, but when the problem will repeat - don't wait and change the coil in Cyl.1
The only other possibilities are bad/low voltage (can you check with your scan tool - voltage on idling? Also plugs may go bad, but plugs don't go bad suddenly, like coils do. What mileage do you have right now? Do you know if anything (coils/plugs, alternator) were changed earlier?
P.S. Coils are number 1 cause when you have such symptoms, especially on E9X series

[lordbmw]

Originally Posted by WhiteBeard

Absolutely, coils (winding) are heat sensitive and cold weather may have expanded range of temperatures they have to work in. From cold starts to the max temp they heat up during normal operation. I'm sure if coil started to go bad - it will repeat itself and you'll get same issue. You can wait until then to be sure if you want. Nothing really bad will happen, but when the problem will repeat - don't wait and change the coil in Cyl.1
The only other possibilities are bad/low voltage (can you check with your scan tool - voltage on idling? Also plugs may go bad, but plugs don't go bad suddenly, like coils do. What mileage do you have right now? Do you know if anything (coils/plugs, alternator) were changed earlier?
P.S. Coils are number 1 cause when you have such symptoms, especially on E9X series

I have 41K miles on the odometer.

I don't know what's been done to the car before I owned it. My battery was changed like 2 weeks ago so I doubt it's my battery but I'll check later.

I've ordered an ignition coil from Amazon, will get it in a few days.

[WhiteBeard]

Originally Posted by lordbmw

I have 41K miles on the odometer.

I don't know what's been done to the car before I owned it. My battery was changed like 2 weeks ago so I doubt it's my battery but I'll check later.

I've ordered an ignition coil from Amazon, will get it in a few days.

41K miles - you can exclude plugs for sure. It's coil, there is nothing else, especially when code is thrown. Was there any issues why battery was changed or it was just before sale kind of stuff?

P.S. if you watched in video I posted - they got wrong coil, make sure you get proper one

[lordbmw]

Originally Posted by WhiteBeard

41K miles - you can exclude plugs for sure. It's coil, there is nothing else, especially when code is thrown. Was there any issues why battery was changed or it was just before sale kind of stuff?

I replaced the battery because it was getting weak. It failed a load test. I think it was the original battery since it was a BMW battery.

I'm pretty confident that it's an ignition coil issue now. But i'll do that test shown in that video to be sure.

BTW, I ordered this:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I only purchased one since I'm only having problems with cylinder 1.
Free shipping too for only $23.76 - not bad.

[Deluxx3]

Originally Posted by Black n54is

That snowflake appeared because your cylinder 1 got too cold and misfired as a result. Probably lost compression...possibly blew a hole in the cylinder wall allowing outside air in. You're fucked

Uhmmmmm wut? Isn't that what you get every time when temp hits 37 degrees F?

[Efthreeoh]

OP, the coil test procedure is not good for the coils and unnecessary because the code tells you its cylinder No. 1 (the front cylinder). A misfire can also be the result of a bad fuel injector. Usually when a coil goes bad it stays bad. Fuel injectors are more prone to be intermittent. If you want to do the coil test you need to have a plug attached to it so it can disperse the energy by firing the spark plug.

[racermp]

Is it just too early and I'm reading this wrong or is this a serious question?

How do you think you need a new engine based on a missfire....

[lordbmw]

Originally Posted by racermp

Is it just too early and I'm reading this wrong or is this a serious question?

How do you think you need a new engine based on a missfire....

It's a serious question. Obviously I don't need a new engine.

[Deluxx3]

OP, I have a similar issue except my 'Service Engine Soon' light came on and does not go away. Running a scan reveals that Cyl. 4 is misfiring. I'll order a new coil and see if that is the issue. It cannot be the spark plugs simply because I got them replace like five thousand miles ago.

On top of that my left headlight ballast is dying so the left headlight only turns on when it wants to and changing the ballast is too much work so unless I get pulled over for it, I guess I'll keep it like that until it gets warm :/

Anyway, good luck and I hope you can resolve your issue.

[racermp]

Originally Posted by lordbmw

It's a serious question. Obviously I don't need a new engine.

Haha coo, from working on car for atleast 20 years now, start with plugs. Keep the coil packs in the same location. See if the light comes back, second if it does on cyl 1, move coil pack to say cyl 2.

[lordbmw]

Originally Posted by Deluxx3

OP, I have a similar issue except my 'Service Engine Soon' light came on and does not go away.

Yea, that's something that's been bugging me.

Why did my 'Service Engine Soon' light go away and yours did not?

I don't really know what BMW's logic for displaying that warning is. Perhaps if it see the same problem more than once, it'll stay lit or perhaps if the problem is present for longer than a certain time, it'll stay lit. Or perhaps it'll stay lit so long as the problem is detected. I dunno.

[BeastMode335i]

Originally Posted by Black n54is

That snowflake appeared because your cylinder 1 got too cold and misfired as a result. Probably lost compression...possibly blew a hole in the cylinder wall allowing outside air in. You're fucked

lmao...