Misfiring and rough idle after oil change

danfratamico · 08-22-2018, 09:22 PM

Changed my oil with 0W-40 on my N54 and filled it with 7 quarts. I noticed my oil filter was twisted a little, but could have been when I unscrewed the oil filter housing. Anyway, I checked the oil level and it showed up as max. Drove it for 20 miles and it was fine. Took it out the next day and drove another 20 miles. Towards the end of the trip, it started to misfire and within 5 minutes, my car sounded like a machine gun. Pulled my coil packs and there was oil in cylinder 2. Cleaned it up and observed all plugs, all were white color and not fouled. Started the car and same issue...misfiring when idling but not under load. I suspect I filled the car with too much oil and that might be causing a vacuum issue. VCG was changed about 6 months ago, so I don't believe that's the cause of the oil in the spark plug well. I may have dropped some oil when filling it up.

OTO335i · 08-23-2018, 01:49 PM

Quote:

Originally Posted by danfratamico

Changed my oil with 0W-40 on my N54 and filled it with 7 quarts. I noticed my oil filter was twisted a little, but could have been when I unscrewed the oil filter housing. Anyway, I checked the oil level and it showed up as max. Drove it for 20 miles and it was fine. Took it out the next day and drove another 20 miles. Towards the end of the trip, it started to misfire and within 5 minutes, my car sounded like a machine gun. Pulled my coil packs and there was oil in cylinder 2. Cleaned it up and observed all plugs, all were white color and not fouled. Started the car and same issue...misfiring when idling but not under load. I suspect I filled the car with too much oil and that might be causing a vacuum issue. VCG was changed about 6 months ago, so I don't believe that's the cause of the oil in the spark plug well. I may have dropped some oil when filling it up.

The amount of oil these cars take is 6.5 Liters (6.8 quarts) so you did add a little too much. If you changed your VCG 6 months ago and you're still getting oil where the coil packs sit on the plug I would say that the gasket did not sit properly around the spark plug holes. I would redo the gaskets and make sure you have the correct amount of oil and try again to see.

danfratamico · 08-23-2018, 02:28 PM

I only noticed the oil in the spark plug well immediately after I changed the oil and filled too much. I believe the extra oil in the system worked on the VCG and the pressure caused it to crack and leak. On a trip now, but when I return I will siphon out 1/2 quart and see what happens. I'll ignore the spark plug well leak for now, until I start to smell oil after trips.

danfratamico · 09-06-2018, 08:54 AM

I siphoned some oil out, same issue. I am now getting the following error codes in ISTA, see image. Seems to me like I have a failing HPFP. Thoughts?

arhoads335i · 09-06-2018, 10:38 AM

could be DME MOSFETS

danfratamico · 09-06-2018, 10:41 AM

Hmm interesting. I am picking up 6 Bosch coil packs today and installing them later. Will give an update, but will also see how easy it is to check the MOSFETS.

danfratamico · 09-06-2018, 03:27 PM

New coils, same issue. Will try plugs next.

wrrush · 09-07-2018, 09:55 AM

if you are getting coil packs go over to bavarian auto and pick up the higher performance ones, they are about the same price, or if you never want a misfire again go to precision raceworks and get this

http://www.precisionraceworks.com/in...&product_id=82

no not affiliated with either

danfratamico · 09-10-2018, 11:14 AM

Update: I soldered on 6 new MOSFETs and the car starts and idles just fine now. When the car heats up, it misfires again. Got a code for cylinder 6 misfire. Moved that coil to cylinder 3 and got a cylinder 3 misfire code. Hopefully replacing that coil should fully solve my issues.

danfratamico · 12-06-2018, 09:00 AM

Realized I never provided an update... I had one bad coil. Replacing it solved the issue completely.

nissubaru · 12-07-2018, 01:57 PM

Quote:

Originally Posted by danfratamico

Realized I never provided an update... I had one bad coil. Replacing it solved the issue completely.

Sounds like you had bad MOSFETs first though? You said earlier in the thread you replaced the coils but it wasn't the solution. Then you mentioned replacing the MOSFETs and the car idled fine but you still had a misfire on one cylinder.

danfratamico · 12-07-2018, 01:58 PM

Yes, correct. When I replaced all six coils, it did not solve the issue because of my failed MOSFET. I replaced all MOSFETs and tracked down which coil that MOSFET took out when it failed. After replacing the MOSFETs and coil (cylinder 4), issue resolved.

08-22-2018, 09:22 PM	#1
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	Misfiring and rough idle after oil change Changed my oil with 0W-40 on my N54 and filled it with 7 quarts. I noticed my oil filter was twisted a little, but could have been when I unscrewed the oil filter housing. Anyway, I checked the oil level and it showed up as max. Drove it for 20 miles and it was fine. Took it out the next day and drove another 20 miles. Towards the end of the trip, it started to misfire and within 5 minutes, my car sounded like a machine gun. Pulled my coil packs and there was oil in cylinder 2. Cleaned it up and observed all plugs, all were white color and not fouled. Started the car and same issue...misfiring when idling but not under load. I suspect I filled the car with too much oil and that might be causing a vacuum issue. VCG was changed about 6 months ago, so I don't believe that's the cause of the oil in the spark plug well. I may have dropped some oil when filling it up.
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08-23-2018, 02:28 PM	#3
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	I only noticed the oil in the spark plug well immediately after I changed the oil and filled too much. I believe the extra oil in the system worked on the VCG and the pressure caused it to crack and leak. On a trip now, but when I return I will siphon out 1/2 quart and see what happens. I'll ignore the spark plug well leak for now, until I start to smell oil after trips.
	Appreciate 0 Quote

09-06-2018, 08:54 AM	#4
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	I siphoned some oil out, same issue. I am now getting the following error codes in ISTA, see image. Seems to me like I have a failing HPFP. Thoughts? Attached Images
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09-06-2018, 10:38 AM	#5
arhoads335i Captain 180 Rep 772 Posts Drives: 2015 435i grand coupe xdrive Join Date: Jan 2017 Location: Philadelphia, PA iTrader: (3) Garage List 2008 BMW 128I [0.00]	could be DME MOSFETS __________________ 2015 435i grand coupe xdrvie (current) 2006 F250 powerstoke CCSB (current) 2014 M235i Black on Red (SOLD) / 08 e90 335i MT Pure Stage 2 High flow (SOLD) 08 128i 6MT (SOLD) / 08 335i 6MT Pure stage 1 (SOLD)
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09-06-2018, 10:41 AM	#6
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	Hmm interesting. I am picking up 6 Bosch coil packs today and installing them later. Will give an update, but will also see how easy it is to check the MOSFETS.
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09-06-2018, 03:27 PM	#7
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	New coils, same issue. Will try plugs next.
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09-07-2018, 09:55 AM	#8
wrrush Second Lieutenant 24 Rep 213 Posts Drives: 2007 335xi Join Date: Jun 2011 Location: Maryland iTrader: (1)	if you are getting coil packs go over to bavarian auto and pick up the higher performance ones, they are about the same price, or if you never want a misfire again go to precision raceworks and get this http://www.precisionraceworks.com/in...&product_id=82 no not affiliated with either
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09-10-2018, 11:14 AM	#9
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	Update: I soldered on 6 new MOSFETs and the car starts and idles just fine now. When the car heats up, it misfires again. Got a code for cylinder 6 misfire. Moved that coil to cylinder 3 and got a cylinder 3 misfire code. Hopefully replacing that coil should fully solve my issues.
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12-06-2018, 09:00 AM	#10
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	Realized I never provided an update... I had one bad coil. Replacing it solved the issue completely.
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12-07-2018, 01:58 PM	#12
danfratamico Private 17 Rep 92 Posts Drives: 2007 BMW 335xi Join Date: Jun 2015 Location: Elkins Park, PA iTrader: (0) Garage List 2007 BMW 335xi [0.00]	Yes, correct. When I replaced all six coils, it did not solve the issue because of my failed MOSFET. I replaced all MOSFETs and tracked down which coil that MOSFET took out when it failed. After replacing the MOSFETs and coil (cylinder 4), issue resolved.
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