The misfires got bad

Manual Transmission · 11-16-2020, 11:57 PM

Recently my manual transmission N51 powered 2008 128i has been misfiring under load. Misfires get worse as the engine warms up. Seems to get worse as the engine warms up. About a year ago/15K miles ago BMW replaced the spark plugs under warranty.

When cold: Idles well. Accelerates well. Maybe a miss or two when accelerating but over all good.

Starting to get warm: Still idles well. Starts to misfire a bit when accelerating between 1500-3500RPM. Cruising at neighborhood or highway speed is smooth with maybe a few misses.

When very warm(45+ minutes running/driving): Idle feels like I've lost a cylinder or is consistently missing. Much vibration. When stopped in neutral I'll hold it at 2K RPM since it runs smooth then. When accelerating it misses a ton, but still is able to accelerate to speed and hit 80-90MPH. Cruising on the highway between 3-4K has a lot of misfires but less than when accelerating. Dropping down to 4th at 4-6K on the highway is much more smooth but still missed a bit. I've only had one trip long enough to have this happen and nearly turned around but decided to keep going because after pulling off the highway it ran better. Haven't driven since.

Bonus Question: I need new rims because mine are bent or off balance, but want to stick with the same size/offset since my car is lowered. Currently sitting on some style 140s 7x16 ET 44. I'd like something lighter weight/better handling but still stock looking. I'd love to hear suggestions. No budget, I like good value but will pay for top quality.

lemansblau135is · 11-17-2020, 03:05 AM

Others can chime in as I'm very new to this, but...

Codes?

Lester · 11-17-2020, 10:14 AM

It could be coils, or VANOS solonoids. If you want to try looking at it yourself, there are quite a few youtube videos on these topics. How many miles? Codes would help, get Carly or something similar.

E92William · 11-17-2020, 01:37 PM

Alright so without codes you're a bit at a loss. Easiest/cheapest ways to scan these cars IMO are the BAFX OBD2 Bluetooth adapter which is 20 bucks and the bmw deep obd app on android, that will let you see all codes that inpa does. Other option is with a laptop and a bimmergeeks kdcan cable you can download inpa from their website and use that. Then you can start diagnosing from there. Sucks to buy parts to throw at a car without knowing what the issue is

lemansblau135is · 11-19-2020, 12:56 PM

For the bonus question: Any OEM 1 series will fit. But depending on how much you're lowered, how wide are the tires you want to run or how much camber you're running, you might need aftermerket wheels or risk rubbing on something. Our choices are kinda limited, but a few exist. I personally bought a used set of +1 inch wider Apex with the recommended offsets from another member.

blackberryq10android · 11-19-2020, 06:57 PM

Usually with coils once they go completely bad you will get a code. If they are somewhat bad but functional the engine will start to rattle and you will hear/feel a difference with your engine. I did not have your symptoms but I have been through a few coils and only have 48k miles, one might be going that may cause issues but like i said I never had your symptoms

m_thompson · 11-20-2020, 09:08 AM

If you still have the SULEV warranty, just take it to the dealer and let them fix it for free.

GCB Mark · 01-01-2021, 06:31 PM

Get a code. I would guess either a coil problem or crankshaft position sensor.

blackberryq10android · 01-04-2021, 12:19 AM

Quote:

Originally Posted by m_thompson

If you still have the SULEV warranty, just take it to the dealer and let them fix it for free.

Yep do Thompson's recommendation, win win situation

11-16-2020, 11:57 PM	#1
Manual Transmission Private First Class 30 Rep 158 Posts Drives: E90 Join Date: Sep 2016 Location: California iTrader: (0)	The misfires got bad Recently my manual transmission N51 powered 2008 128i has been misfiring under load. Misfires get worse as the engine warms up. Seems to get worse as the engine warms up. About a year ago/15K miles ago BMW replaced the spark plugs under warranty. When cold: Idles well. Accelerates well. Maybe a miss or two when accelerating but over all good. Starting to get warm: Still idles well. Starts to misfire a bit when accelerating between 1500-3500RPM. Cruising at neighborhood or highway speed is smooth with maybe a few misses. When very warm(45+ minutes running/driving): Idle feels like I've lost a cylinder or is consistently missing. Much vibration. When stopped in neutral I'll hold it at 2K RPM since it runs smooth then. When accelerating it misses a ton, but still is able to accelerate to speed and hit 80-90MPH. Cruising on the highway between 3-4K has a lot of misfires but less than when accelerating. Dropping down to 4th at 4-6K on the highway is much more smooth but still missed a bit. I've only had one trip long enough to have this happen and nearly turned around but decided to keep going because after pulling off the highway it ran better. Haven't driven since. Bonus Question: I need new rims because mine are bent or off balance, but want to stick with the same size/offset since my car is lowered. Currently sitting on some style 140s 7x16 ET 44. I'd like something lighter weight/better handling but still stock looking. I'd love to hear suggestions. No budget, I like good value but will pay for top quality. Last edited by Manual Transmission; 11-17-2020 at 12:19 AM..
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11-17-2020, 03:05 AM	#2
lemansblau135is First Lieutenant 119 Rep 359 Posts Drives: bmw 135is Join Date: Apr 2019 Location: nor cal iTrader: (0) Garage List 2013 bmw 135is [0.00]	Others can chime in as I'm very new to this, but... Codes?
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11-17-2020, 10:14 AM	#3
Lester Brigadier General 295 Rep 3,350 Posts Drives: Join Date: Oct 2007 iTrader: (0)	It could be coils, or VANOS solonoids. If you want to try looking at it yourself, there are quite a few youtube videos on these topics. How many miles? Codes would help, get Carly or something similar. __________________ 2008 135i, Jet Black, 6 spd, Canadian Sport package, black leatherette, manual seats, aluminum glacier trim, PDC. 1983 E21 Delphin, M10, 5 speed, LSD, MSW wheels, recaro seats, Hartge strut brace, rear sway bar. [SIGPIC][/SIGPIC]
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11-17-2020, 01:37 PM	#4
E92William Banned 1998 Rep 2,026 Posts Drives: 2008 E92 328xi Join Date: Nov 2019 Location: Miami iTrader: (0) Garage List 2008 BMW 328xi [0.00]	Alright so without codes you're a bit at a loss. Easiest/cheapest ways to scan these cars IMO are the BAFX OBD2 Bluetooth adapter which is 20 bucks and the bmw deep obd app on android, that will let you see all codes that inpa does. Other option is with a laptop and a bimmergeeks kdcan cable you can download inpa from their website and use that. Then you can start diagnosing from there. Sucks to buy parts to throw at a car without knowing what the issue is
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11-19-2020, 12:56 PM	#5
lemansblau135is First Lieutenant 119 Rep 359 Posts Drives: bmw 135is Join Date: Apr 2019 Location: nor cal iTrader: (0) Garage List 2013 bmw 135is [0.00]	For the bonus question: Any OEM 1 series will fit. But depending on how much you're lowered, how wide are the tires you want to run or how much camber you're running, you might need aftermerket wheels or risk rubbing on something. Our choices are kinda limited, but a few exist. I personally bought a used set of +1 inch wider Apex with the recommended offsets from another member.
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11-19-2020, 06:57 PM	#6
blackberryq10android Private First Class 22 Rep 101 Posts Drives: BMW 128i 2009 Convertible Join Date: Oct 2018 Location: NY iTrader: (0)	Usually with coils once they go completely bad you will get a code. If they are somewhat bad but functional the engine will start to rattle and you will hear/feel a difference with your engine. I did not have your symptoms but I have been through a few coils and only have 48k miles, one might be going that may cause issues but like i said I never had your symptoms
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11-20-2020, 09:08 AM	#7
m_thompson Major 133 Rep 1,416 Posts Drives: M-Sport 128i, 328xi, 3.0CS Join Date: Jun 2008 Location: New England, USA iTrader: (0) Garage List 2009 128i [0.00] 1972 3.0CS [10.00]	If you still have the SULEV warranty, just take it to the dealer and let them fix it for free. __________________ '09 128i - Black Sapphire Metallic\Coral Red\Glacier Silver\N51 DISA\6MT\Navigation\Premium\M-Sport\Heated seats\Xenon\Headlights\iPod\Smartphone\Euro Delivery
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01-01-2021, 06:31 PM	#8
GCB Mark New Member 5 Rep 5 Posts Drives: 2011 BMW E88 128i Join Date: Dec 2020 Location: Myrtle Beach iTrader: (0) Garage List 2017 Subaru Outback ... [0.00] 2011 128i E88 [0.00]	Get a code. I would guess either a coil problem or crankshaft position sensor.
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