BMW firing with no codes

blingman · 11-06-2011, 01:43 PM

Car was running fine, next day weather was cold in the 30s, starting it up and car was studdering, drove down the street and got CEL P0304. Found out that misfiring in cylinder 4. I replaced all spark plugs and car started it up and car still hick up with same P0304 code. I swapped coil 1 and 4 to see if the code will change to misfiring on cylinder 1 to confirm its the coil pack that's gone bad. Start car up and car idled a lot smoother, but when I gave it some gas, the car would studder/shake more. It's not throwing any codes. Any help or suggestions?

faboR6 · 11-07-2011, 06:31 PM

Quote:

Originally Posted by blingman

Car was running fine, next day weather was cold in the 30s, starting it up and car was studdering, drove down the street and got CEL P0304. Found out that misfiring in cylinder 4. I replaced all spark plugs and car started it up and car still hick up with same P0304 code. I swapped coil 1 and 4 to see if the code will change to misfiring on cylinder 1 to confirm its the coil pack that's gone bad. Start car up and car idled a lot smoother, but when I gave it some gas, the car would studder/shake more. It's not throwing any codes. Any help or suggestions?

Same thing happened to me. I replaced Coils 1 and 3 and it worked fine again. You migh want to get a new or good coil and start mixing them around and pay attention to which one it start shaking at. Make sure you remember where the good coil came from. Good luck

J02 335i · 11-07-2011, 06:51 PM

You need to get the car diagnosed, just replacing parts and hoping for the best is expensive. You could have a vacuum leak, bad injector, no compression (highly unlikely) and the list goes on. Just remember a misfire is not always ignition related.

blingman · 11-07-2011, 07:12 PM

Thanks guys! I swapped the coil to different cylinder and got another code confirmation for that cylinder confirming its that code but just to make sure I swap that same coil over to another one and got another code for that cylinder so its confirmed it is that coil. I went to BMW and bought a coil and replaced it and its up and running smooth

Thanks!

11-06-2011, 01:43 PM	#1
blingman Lieutenant 40 Rep 413 Posts Drives: 3er Join Date: Mar 2011 Location: Houston iTrader: (2)	BMW firing with no codes Car was running fine, next day weather was cold in the 30s, starting it up and car was studdering, drove down the street and got CEL P0304. Found out that misfiring in cylinder 4. I replaced all spark plugs and car started it up and car still hick up with same P0304 code. I swapped coil 1 and 4 to see if the code will change to misfiring on cylinder 1 to confirm its the coil pack that's gone bad. Start car up and car idled a lot smoother, but when I gave it some gas, the car would studder/shake more. It's not throwing any codes. Any help or suggestions?
	Appreciate 0 Tweet Quote

11-07-2011, 06:51 PM	#3
J02 335i Lieutenant Colonel 39 Rep 1,558 Posts Drives: F80 M3 Join Date: Aug 2010 Location: Ontario iTrader: (1)	You need to get the car diagnosed, just replacing parts and hoping for the best is expensive. You could have a vacuum leak, bad injector, no compression (highly unlikely) and the list goes on. Just remember a misfire is not always ignition related. __________________ Sport pack, JB3, Dci, factory oil cooler, 18" M3 reps, Michelin PSS, painted trim, black grills, smoked side markers, LED plate lights, H&R coils, Borla catback
	Appreciate 0 Quote

11-07-2011, 07:12 PM	#4
blingman Lieutenant 40 Rep 413 Posts Drives: 3er Join Date: Mar 2011 Location: Houston iTrader: (2)	Thanks guys! I swapped the coil to different cylinder and got another code confirmation for that cylinder confirming its that code but just to make sure I swap that same coil over to another one and got another code for that cylinder so its confirmed it is that coil. I went to BMW and bought a coil and replaced it and its up and running smooth Thanks!
	Appreciate 0 Quote