Rmp fluctuation after vc job / strange knock

N52dj · 01-25-2023, 10:15 PM

I have a 2008 bmw 128i n52 automatic
Liquid Molly oil 5w30
This issue didn’t happen before the vc job, people r saying loose spark plugs

Just replaced valve cover and all seals
Spark plugs and coils w bosh
Pullies and belt/ Alternator
Oil filter housing gasket
New oil / filter

When starting now the engine seems to knock more from the Valvetronic side of the engine , I tried to attach a video
It does go away after driving about 5-10 mins
Rmps will fluctuate at weird times , ex. Reverse to drive , closing door only not opening , when driving but mostly at idle or slow speeds most noticeable , NO CODES OR CEL
I’ve only started the car a handful of times since the vc job, and drove it once or twice with rmp fluctuations but zero codes or issues otherwise
no leaks of oil to be found , i repulled all covers and retorqued sparks / all vc bolts

spidertri · 01-26-2023, 08:46 AM

Sounds like air is getting in somewhere after the MAF and causing the rough running. Does taking the oil fill cap off when it's doing it make it change?

What brand valve cover? Genuine BMW or aftermarket? Some of the aftermarket covers are known to have issues.

Papa Popov · 01-26-2023, 06:32 PM

Had some similar issues with mine after doing my VCG. Sounds like you've already check those so if its not the coils I'd check the eccentric shaft sensor. You might've gotten some oil in there which causes all kinds of issues and doesn't always throw a code. For reference, before I replaced mine my RPMs would fluctuate enough to make the whole car shake for a few seconds on cold start.

01-25-2023, 10:15 PM	#1
N52dj Registered 2 Rep 3 Posts Drives: Bmw e82 12i Join Date: Jan 2023 Location: Massachusetts iTrader: (0)	Rmp fluctuation after vc job / strange knock I have a 2008 bmw 128i n52 automatic Liquid Molly oil 5w30 This issue didn’t happen before the vc job, people r saying loose spark plugs Just replaced valve cover and all seals Spark plugs and coils w bosh Pullies and belt/ Alternator Oil filter housing gasket New oil / filter When starting now the engine seems to knock more from the Valvetronic side of the engine , I tried to attach a video It does go away after driving about 5-10 mins Rmps will fluctuate at weird times , ex. Reverse to drive , closing door only not opening , when driving but mostly at idle or slow speeds most noticeable , NO CODES OR CEL I’ve only started the car a handful of times since the vc job, and drove it once or twice with rmp fluctuations but zero codes or issues otherwise no leaks of oil to be found , i repulled all covers and retorqued sparks / all vc bolts
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01-26-2023, 08:46 AM	#2
spidertri Lieutenant 398 Rep 464 Posts Drives: 11 128i 6MT Sport Join Date: Sep 2010 Location: Rock Hill, SC iTrader: (1) Garage List 2011 BMW 128i [0.00]	Sounds like air is getting in somewhere after the MAF and causing the rough running. Does taking the oil fill cap off when it's doing it make it change? What brand valve cover? Genuine BMW or aftermarket? Some of the aftermarket covers are known to have issues. __________________ 11 128i slicktop 13 WK2 19 Alltrack S
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01-26-2023, 06:32 PM	#3
Papa Popov Lieutenant 315 Rep 474 Posts Drives: 2009 128i 6MT Join Date: Mar 2020 Location: SoCal iTrader: (0) Garage List 2009 BMW 128i Coupe [0.00]	Had some similar issues with mine after doing my VCG. Sounds like you've already check those so if its not the coils I'd check the eccentric shaft sensor. You might've gotten some oil in there which causes all kinds of issues and doesn't always throw a code. For reference, before I replaced mine my RPMs would fluctuate enough to make the whole car shake for a few seconds on cold start.
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