E92 very rough idle

autoAER · 10-21-2016, 01:51 PM

Hi everyone,
I recently did a valve cover gasket change, and car started right up just fine. However, in the past few days, now it's been having an incredibly rough idle, and just a rough idle, the revs smooth out and you feel no misfire at higher rpms. What could be a possible cause for this? I'd rather not redo the valve cover gasket if possible

Thanks in advance!

autoAER · 10-21-2016, 02:05 PM

I just plugged in the code reader and I basically have a misfire in all cylinders, and on top of that it says coolant temperature sensor, measurement . Not sure what could be wrong as the valve cover is sealed and I haven't been losing oil!

Eddien123 · 10-22-2016, 12:53 AM

You pulled a lot of electronics and every plug and coil so perhaps a lose connection somewhere? Also I'm thinking it could be something with the valvetronic motor but I'm almost positive that when you turn on the ignition without starting the car it auto adjusts back into place.

autoAER · 10-22-2016, 09:15 AM

Quote:

Originally Posted by Eddien123

You pulled a lot of electronics and every plug and coil so perhaps a lose connection somewhere? Also I'm thinking it could be something with the valvetronic motor but I'm almost positive that when you turn on the ignition without starting the car it auto adjusts back into place.

If the valvetronic motor isn't correctly re-installed, would it cause a misfire in all cylinders?? Thanks for the response!

PhaseP · 10-22-2016, 12:51 PM

I would check electrical connections, especially the ground strap that grounds the electrical harness on top of the valve cover to the ground on the chassis.

autoAER · 10-22-2016, 08:42 PM

Quote:

Originally Posted by PhaseP

I would check electrical connections, especially the ground strap that grounds the electrical harness on top of the valve cover to the ground on the chassis.

The grounds are in place, connected. I'm starting to give up, I removed and re-installed the valvetronic motor, looked ok to me. The car now idles very rough for maybe 30 or so seconds then I think the engine adjusts and the rough idle goes away, albeit with a low (500-550rpm) idle speed.

PhaseP · 10-22-2016, 09:50 PM

One other thing possible, some section of the valve cover gasket rolled over and pinched during installation causing vacuum leak. It is not uncommon to happen. Check all around the valve cover to verify the gasket is in correct position. An inspection mirror will help to see. But it would also have some small oil leak in the area if this happened.

bmw325i · 10-22-2016, 09:56 PM

Check your valvetronic sensor. There is usually oil inside the connection when they go out. I would think it would give you a different code for that, but it's worth checking.

BSM n54iS · 10-22-2016, 10:36 PM

Are the only codes you're getting is misfire? Nothing about your o2 sensors/running lean or anything? Had the dealer replace my vcg under warranty and 'coincidentally' my rear o2 sensor went bad causing misfires

Eddien123 · 10-23-2016, 01:18 AM

Quote:

Originally Posted by autoAER

Quote:

Originally Posted by Eddien123

You pulled a lot of electronics and every plug and coil so perhaps a lose connection somewhere? Also I'm thinking it could be something with the valvetronic motor but I'm almost positive that when you turn on the ignition without starting the car it auto adjusts back into place.

If the valvetronic motor isn't correctly re-installed, would it cause a misfire in all cylinders?? Thanks for the response!

If it isn't correctly lined up and it isn't measuring the rotation of the camshaft correctly then I'm sure that could cause either a fuel delivery issue or a false reading by the computer. I'm just trying to use logic here. It's an easy thing to check. Although I highly suggest you buy a BMW code reader as it will tell you any shadow codes that exist.

autoAER · 11-11-2016, 04:13 PM

Interestingly enough, I switched two of the wires that were clipped to the fuel rail next to the intake manifold, and now the car runs much smoother than before. Theres still a slight roughness to the engine, but I think its because the car has been sitting for close to a month now. I still feel that its not back to its original smooth running though. I removed and reinstalled the valve cover as well. Not sure what could be happening. Code reader just shows misfire and electric coolant pump malfunction, but Check engine light is off for the time being.

juld0zer · 05-22-2019, 05:05 AM

Old thread but switching the o2 sensor connectors will cause the engine to run like that. The N52 has a specific code when this happens and it is capable of detecting a swtiched o2 sensor conection

10-21-2016, 01:51 PM	#1
autoAER Private First Class 48 Rep 104 Posts Drives: Monaco Blue 335i Join Date: Jun 2014 Location: Concord, CA iTrader: (0) Garage List 2011 BMW 328i [0.00] 2006 BMW 330i [5.50]	E92 very rough idle Hi everyone, I recently did a valve cover gasket change, and car started right up just fine. However, in the past few days, now it's been having an incredibly rough idle, and just a rough idle, the revs smooth out and you feel no misfire at higher rpms. What could be a possible cause for this? I'd rather not redo the valve cover gasket if possible Thanks in advance! __________________ Current: 2006 330i Mystic Blue 6MT, 2011 328i Coupe Titan Silver Ex: 2006 330i Barrique Red, 2008 335i Monaco Blue, 2011 335i Deep Sea Blue
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10-21-2016, 02:05 PM	#2
autoAER Private First Class 48 Rep 104 Posts Drives: Monaco Blue 335i Join Date: Jun 2014 Location: Concord, CA iTrader: (0) Garage List 2011 BMW 328i [0.00] 2006 BMW 330i [5.50]	I just plugged in the code reader and I basically have a misfire in all cylinders, and on top of that it says coolant temperature sensor, measurement . Not sure what could be wrong as the valve cover is sealed and I haven't been losing oil!
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10-22-2016, 12:53 AM	#3
Eddien123 Colonel 1857 Rep 2,554 Posts Drives: F30 335 6MT Join Date: May 2013 Location: New Jersey iTrader: (0)	You pulled a lot of electronics and every plug and coil so perhaps a lose connection somewhere? Also I'm thinking it could be something with the valvetronic motor but I'm almost positive that when you turn on the ignition without starting the car it auto adjusts back into place.
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10-22-2016, 12:51 PM	#5
PhaseP Colonel 1007 Rep 2,108 Posts Drives: 325XI Join Date: May 2010 Location: Earth iTrader: (0)	I would check electrical connections, especially the ground strap that grounds the electrical harness on top of the valve cover to the ground on the chassis.
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10-22-2016, 09:50 PM	#7
PhaseP Colonel 1007 Rep 2,108 Posts Drives: 325XI Join Date: May 2010 Location: Earth iTrader: (0)	One other thing possible, some section of the valve cover gasket rolled over and pinched during installation causing vacuum leak. It is not uncommon to happen. Check all around the valve cover to verify the gasket is in correct position. An inspection mirror will help to see. But it would also have some small oil leak in the area if this happened.
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10-22-2016, 09:56 PM	#8
bmw325i Major General 223 Rep 5,120 Posts Drives: 2006 BMW 325i Join Date: Oct 2010 Location: United States iTrader: (8)	Check your valvetronic sensor. There is usually oil inside the connection when they go out. I would think it would give you a different code for that, but it's worth checking.
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10-22-2016, 10:36 PM	#9
BSM n54iS Brigadier General 2685 Rep 4,202 Posts Drives: '11 335is \| '16 Macan Turbo Join Date: Aug 2015 Location: Everywhere and Nowhere iTrader: (7)	Are the only codes you're getting is misfire? Nothing about your o2 sensors/running lean or anything? Had the dealer replace my vcg under warranty and 'coincidentally' my rear o2 sensor went bad causing misfires __________________ '11 335is BSM MT "BMW Performance Editon" \| '16 Porsche Macan Turbo GruppeM CF Intake \| AR Resonated DP \| ER CP \| Turbosmart RacePort BOV \| Cobb FMIC \| RB Inlets \| RB External Mishi/Turner OCC \| Michelin PS4 \| BMW Performance Springs/Bilstein B8 + Dinan & M3 bits \| BMW Brembo BBK \| BMW Performance CF Spoiler \| BMW Performance CF Lip \| BMW Performance Alcantara \| PS Designs GTS Armrest \| AG H6-40 \| Rear Seat Delete
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11-11-2016, 04:13 PM	#11
autoAER Private First Class 48 Rep 104 Posts Drives: Monaco Blue 335i Join Date: Jun 2014 Location: Concord, CA iTrader: (0) Garage List 2011 BMW 328i [0.00] 2006 BMW 330i [5.50]	Interestingly enough, I switched two of the wires that were clipped to the fuel rail next to the intake manifold, and now the car runs much smoother than before. Theres still a slight roughness to the engine, but I think its because the car has been sitting for close to a month now. I still feel that its not back to its original smooth running though. I removed and reinstalled the valve cover as well. Not sure what could be happening. Code reader just shows misfire and electric coolant pump malfunction, but Check engine light is off for the time being. __________________ Current: 2006 330i Mystic Blue 6MT, 2011 328i Coupe Titan Silver Ex: 2006 330i Barrique Red, 2008 335i Monaco Blue, 2011 335i Deep Sea Blue
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05-22-2019, 05:05 AM	#12
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	Old thread but switching the o2 sensor connectors will cause the engine to run like that. The N52 has a specific code when this happens and it is capable of detecting a swtiched o2 sensor conection
	Appreciate 0 Quote