help!! misfiring. anyone know what's causing it ?

E92BA · 02-12-2012, 10:29 PM

I've been misfiring. I was hoping someone might have had the same symptoms and might be able to tell me hat it is before I start buying coil packs and injectors and hope hey work.
-2007 335
-70k miles
-brand new hpfp
-most of the time only misfires when I put it on map 1 on jb4
-misfires on cylinders 4 &5

might be spark plugs ? anyone wanna give it a shot? thanks!!!!

GmoBmw · 02-12-2012, 10:38 PM

haha mine did the same thing. Changed my plugs and it went away. If its not that might wanna check your coils. but most likely its plugs.

reiss91 · 02-12-2012, 10:38 PM

Move the coils and plugs and see if the misfire moves. Assuming you have a scanner to read them.

This should identify if a coil or plug needs to be replaced. If that doesn't help you check the carbon build up on the intake valves. Cylinder 5 is usually always the dirtiest and 70k is about time to get it done.

Keep us posted

skinrock · 02-12-2012, 10:39 PM

http://www.e90post.com/forums/showthread.php?t=631829

E92BA · 02-12-2012, 10:44 PM

yea I'm gonna try the spark plugs. I'm pretty sure that's it. & I wanna do the carbon build up cleaning but it's a lotta $$$

335iVA · 02-14-2012, 05:08 PM

I had the same problem. I first noticed a misfire on Cyl. 4 when in Map 1. I moved to Map 5 and it was running for a month or so, then started misfiring on Cyl. 4 again. The only time it would not misfire was when I was running stock bypass. Changed the plugs, problem fixed. Car has been running smoothly ever since... So check the coils, change the plugs, you should be good to go. Hopefully its not your injectors, but if you are under warranty, shouldn't be a problem. Have you had the injectors replaced yet?

02-12-2012, 10:29 PM	#1
E92BA FBO + e85 335i 3 Rep 80 Posts Drives: E92 335i Join Date: Dec 2011 Location: Miami iTrader: (0)	help!! misfiring. anyone know what's causing it ? I've been misfiring. I was hoping someone might have had the same symptoms and might be able to tell me hat it is before I start buying coil packs and injectors and hope hey work. -2007 335 -70k miles -brand new hpfp -most of the time only misfires when I put it on map 1 on jb4 -misfires on cylinders 4 &5 might be spark plugs ? anyone wanna give it a shot? thanks!!!!
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02-12-2012, 10:38 PM	#2
GmoBmw Captain 34 Rep 645 Posts Drives: 2007 335i Join Date: Dec 2011 Location: California iTrader: (8)	haha mine did the same thing. Changed my plugs and it went away. If its not that might wanna check your coils. but most likely its plugs. __________________ 2007 BMW 335I- JB4 G5,DCI,VRSF DPs,NT555r Drag Radials Daily Driver
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02-12-2012, 10:38 PM	#3
reiss91 New Member 3 Rep 24 Posts Drives: tacoma Join Date: May 2011 Location: usa iTrader: (0)	Move the coils and plugs and see if the misfire moves. Assuming you have a scanner to read them. This should identify if a coil or plug needs to be replaced. If that doesn't help you check the carbon build up on the intake valves. Cylinder 5 is usually always the dirtiest and 70k is about time to get it done. Keep us posted
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02-12-2012, 10:39 PM	#4
skinrock Agent Smith 270 Rep 3,344 Posts Drives: 2016 i8 Join Date: Jan 2011 Location: The Matrix iTrader: (9) Garage List 2016 BMW i8 [10.00]	http://www.e90post.com/forums/showthread.php?t=631829 __________________ The i8 needs a V8 amirite?
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02-12-2012, 10:44 PM	#5
E92BA FBO + e85 335i 3 Rep 80 Posts Drives: E92 335i Join Date: Dec 2011 Location: Miami iTrader: (0)	yea I'm gonna try the spark plugs. I'm pretty sure that's it. & I wanna do the carbon build up cleaning but it's a lotta $$$
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02-14-2012, 05:08 PM	#6
335iVA Chyeah 3 Rep 31 Posts Drives: 07 335i 6MT Join Date: May 2011 Location: California iTrader: (0)	I had the same problem. I first noticed a misfire on Cyl. 4 when in Map 1. I moved to Map 5 and it was running for a month or so, then started misfiring on Cyl. 4 again. The only time it would not misfire was when I was running stock bypass. Changed the plugs, problem fixed. Car has been running smoothly ever since... So check the coils, change the plugs, you should be good to go. Hopefully its not your injectors, but if you are under warranty, shouldn't be a problem. Have you had the injectors replaced yet?
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