Sounds like my car is backfiring! help

Jasboarder05 · 12-10-2013, 05:53 PM

I have a 2013 X3 28i (N20) that is about a year and a half old. After the car was sitting out in the cold (0 degrees F) for about 3 hours, when I started it I heard a loud POP come from the rear of the car. The next day started the car and had the same thing happen. Sounds like the POP came from the exhaust. Anyone else experiencing this? I've never had a vehicle do this before. I'm not a mechanic by any means but would this be from unburnt fuel getting into the exhaust? Hope its not serious. Thanks for your help guys/gals

colson79 · 12-11-2013, 11:23 AM

You should get it looked at by the dealer. I live just a few hours North of you so my X3 has been sitting outside in the cold the last few days as well and I haven't experienced anything like this on my X3. If it happens when starting I don't think the exhaust would be hot enough to ignite fuel but something doesn't seem right.

c3uo · 12-11-2013, 07:42 PM

If it only does it once a few seconds after starting it probably is just the secondary exhaust flap cracking open when first starting the car and it is below freezing. Our 35i does this once a while too in the dead of winter when it gets iced up.

There's a metal flap that opens and closes the second exhaust pipe for initial start and high RPM. Ours stuck a few times last winter in the ice and snow and mat a snap noise when it opened (or closed not sure which position).

It may not be that, but thought it would be something you could check. Once it warmed up for a few days and the ice melted we had no problems.

Jasboarder05 · 12-11-2013, 09:33 PM

Thanks for all the responses. I might bring it by the dealer tomorrow to see what they think. Hopefully i can reproduce the sound for them. Thanks again. I'll post what the dealers response about this issue. thanks again

CBS · 12-16-2013, 07:02 PM

OP: I'd be curious to learn what the Dealer tells you. Our 2.8 X3 did the same thing twice this past weekend a few minutes after start up.

E92LNGCGY · 12-16-2013, 10:55 PM

It is definitely the exhaust flap getting stuck. Had the same loud pop in my 35i and 335. Golf tee mod will keep the flap open all the time and eliminate this noise.

12-10-2013, 05:53 PM	#1
Jasboarder05 New Member 4 Rep 21 Posts Drives: 2013 BMW X3 28i Join Date: May 2012 Location: Madison WI iTrader: (0)	Sounds like my car is backfiring! help I have a 2013 X3 28i (N20) that is about a year and a half old. After the car was sitting out in the cold (0 degrees F) for about 3 hours, when I started it I heard a loud POP come from the rear of the car. The next day started the car and had the same thing happen. Sounds like the POP came from the exhaust. Anyone else experiencing this? I've never had a vehicle do this before. I'm not a mechanic by any means but would this be from unburnt fuel getting into the exhaust? Hope its not serious. Thanks for your help guys/gals
	Appreciate 0 Tweet Quote

12-11-2013, 11:23 AM	#2
colson79 Second Lieutenant 7 Rep 221 Posts Drives: 2012 X3 35i DSB Join Date: Jul 2011 Location: Wisconsin iTrader: (0)	You should get it looked at by the dealer. I live just a few hours North of you so my X3 has been sitting outside in the cold the last few days as well and I haven't experienced anything like this on my X3. If it happens when starting I don't think the exhaust would be hot enough to ignite fuel but something doesn't seem right. __________________ 2012 X3 35i \| Deep Sea Blue \| Oyster \| Packages \| Sports \| Cold Weather \| Cold Weather 2 \| Premium \| Technology \| Premium Sound
	Appreciate 0 Quote

12-11-2013, 07:42 PM	#3
c3uo Private First Class 39 Rep 151 Posts Drives: 3 Series Join Date: Jun 2005 Location: NB iTrader: (0)	If it only does it once a few seconds after starting it probably is just the secondary exhaust flap cracking open when first starting the car and it is below freezing. Our 35i does this once a while too in the dead of winter when it gets iced up. There's a metal flap that opens and closes the second exhaust pipe for initial start and high RPM. Ours stuck a few times last winter in the ice and snow and mat a snap noise when it opened (or closed not sure which position). It may not be that, but thought it would be something you could check. Once it warmed up for a few days and the ice melted we had no problems.
	Appreciate 0 Quote

12-11-2013, 09:33 PM	#4
Jasboarder05 New Member 4 Rep 21 Posts Drives: 2013 BMW X3 28i Join Date: May 2012 Location: Madison WI iTrader: (0)	Thanks for all the responses. I might bring it by the dealer tomorrow to see what they think. Hopefully i can reproduce the sound for them. Thanks again. I'll post what the dealers response about this issue. thanks again
	Appreciate 0 Quote

12-16-2013, 07:02 PM	#5
CBS Major 87 Rep 1,253 Posts Drives: F10535, E90M3, E30M3, E28M5 Join Date: Jan 2011 Location: Charlotte, NC iTrader: (0) Garage List 2017 Alpina B6 GC [0.00] 2014 535xi M Sport [0.00] 2014 X3 3.5 M Sport [0.00] 2011 M3 E90 [9.74] 2007 Z4 M Coupe [7.00] 1990 M3 [9.50] 1988 M5 [10.00]	OP: I'd be curious to learn what the Dealer tells you. Our 2.8 X3 did the same thing twice this past weekend a few minutes after start up. __________________ ESS VT-1 550 \| M24 Oil Cooler \| Fall Line Half Cage \| RaceTech 4009W \| 6 pt Harness \| Lifeline Zero 360 Fire Suppression \| Rear Seat Delete \| Motion Control DA Dampers w/remote reservoirs \| 900/650 Hyperco Springs \| RD Sport Sway Bars \| Brembo 380 BBK \| GC Camber Plates \| Hoosier R7 \| Eisenmann Sport \| Stack Gauges \| Painted Challenge Front Lip \| Painted ZCP Rear Spoiler \| Xpel Ultimate Film \| LuxAngelEyes
	Appreciate 0 Quote

12-16-2013, 10:55 PM	#6
E92LNGCGY Lieutenant Colonel 433 Rep 1,732 Posts Drives: F97/Q5/982 GT4 Join Date: Jan 2011 Location: Canada iTrader: (0)	It is definitely the exhaust flap getting stuck. Had the same loud pop in my 35i and 335. Golf tee mod will keep the flap open all the time and eliminate this noise.
	Appreciate 0 Quote

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search