N52 Start Up Problem

rsandhu7 · 02-08-2018, 02:07 AM

https://youtu.be/wzCxTa1TDCs

Every time i do a cold start it in the morning, this happens and the rpm bounce like crazy. It usually does not start the first crank but switches on when you try the second time. After like 20 seconds, everythings back to normal..no signs show up on dash and i've also replaced a couple of sensors but it still hasn't stopped doing that. Car starts up completely fine when its warm. Any ideas whats wrong?

TGTIW · 02-08-2018, 08:10 AM

My guess, Eccentric Shaft Position Sensor.

N54_e90 · 02-23-2018, 06:50 PM

Vauum leak? There is also a DME update to fix fluctuating idle on start up, might want to look into it.

Three_thirty_I · 02-24-2018, 12:28 AM

When last have you cleaned the Vanos solenoids? I would try that and then swap them around when putting them back.

Which sensors have you replaced, and what else have you done so far to fix this?

mattoak · 02-27-2018, 03:03 PM

Also you can check the eccentric shaft sensor fairly easily. Have to remove the engine cover but after that the connector sits right on top of the valve cover. I had some rough starts when cold (winter cold) and checked the eccentric shaft sensor and there was oil in there. INPA code readout told me it was plausible (or whatever they call it) on the eccentric shaft sensor so I knew it was time to replace. '06 with 154k miles. I did the eccentric shaft sensor, valve cover gasket, cleaned vanos solenoids, and valvetronic gasket for good measure. Took like 6-7 hours.

If you are still low miles just try cleaning the vanos solenoids that might help. But I'd also check the eccentric shaft sensor for oil. If there's oil, plan on changing it soon and then you can clean the vanos while you're at it.

02-08-2018, 02:07 AM	#1
rsandhu7 Registered 0 Rep 2 Posts Drives: 323i Join Date: Jun 2015 Location: BC iTrader: (0)	N52 Start Up Problem https://youtu.be/wzCxTa1TDCs Every time i do a cold start it in the morning, this happens and the rpm bounce like crazy. It usually does not start the first crank but switches on when you try the second time. After like 20 seconds, everythings back to normal..no signs show up on dash and i've also replaced a couple of sensors but it still hasn't stopped doing that. Car starts up completely fine when its warm. Any ideas whats wrong?
	Appreciate 0 Tweet Quote

02-08-2018, 08:10 AM	#2
TGTIW Second Lieutenant 130 Rep 245 Posts Drives: 2010 328i Join Date: May 2013 Location: Knoxville iTrader: (2)	My guess, Eccentric Shaft Position Sensor.
	Appreciate 1 Efthreeoh17376.50 Quote

02-23-2018, 06:50 PM	#3
N54_e90 Don 46 Rep 299 Posts Drives: '09 E90 335xi Family Sedan Join Date: Jan 2017 Location: Your Mother's House iTrader: (0)	Vauum leak? There is also a DME update to fix fluctuating idle on start up, might want to look into it.
	Appreciate 0 Quote

02-24-2018, 12:28 AM	#4
Three_thirty_I Lieutenant Colonel 200 Rep 1,834 Posts Drives: '05 E90 330i Manual Join Date: Aug 2010 Location: Cape Town, South Africa iTrader: (0) Garage List 2005 BMW E90 330i [0.00]	When last have you cleaned the Vanos solenoids? I would try that and then swap them around when putting them back. Which sensors have you replaced, and what else have you done so far to fix this? __________________ BMW E90 330i (M) '05 (His) \| (Hers) BMW E46 320i f/l (M) '03
	Appreciate 0 Quote

02-27-2018, 03:03 PM	#5
mattoak Private First Class 9 Rep 114 Posts Drives: 06 325i Join Date: Oct 2013 Location: Fort Collins, CO iTrader: (0)	Also you can check the eccentric shaft sensor fairly easily. Have to remove the engine cover but after that the connector sits right on top of the valve cover. I had some rough starts when cold (winter cold) and checked the eccentric shaft sensor and there was oil in there. INPA code readout told me it was plausible (or whatever they call it) on the eccentric shaft sensor so I knew it was time to replace. '06 with 154k miles. I did the eccentric shaft sensor, valve cover gasket, cleaned vanos solenoids, and valvetronic gasket for good measure. Took like 6-7 hours. If you are still low miles just try cleaning the vanos solenoids that might help. But I'd also check the eccentric shaft sensor for oil. If there's oil, plan on changing it soon and then you can clean the vanos while you're at it.
	Appreciate 0 Quote