2011 E92 330d N57, rough idle

dirxnce · 04-18-2026, 07:15 AM

Hi guys, ive picked up a 161000 kms e92 recently and it has been having a rough idle recently with the rpms fluctuating slightly for a bit before going back to normal. Ive got codes 4A1E, 4A14 and A670. Does this mean I have a failed glow plug and is that the cause of the rough idle. I am new to the N57 engine and dont really know alot about it. thanks

jaffles · 04-18-2026, 01:09 PM

Glow plugs are for starting, and glow plug controller keeps the plugs glowing while engine is cold until it warms up. Once warm engine should run smooth without both.

I imagine checking the resistance on each glow plug will reveal which might be faulty. However 4A1E indicates cylinder 6, closest to firewall.

Not sure how to check the glow plug controller, but if the car blows white vapor for a minute or so when starting cold, its a controller. It can be replaced without removing the induction box, but its fiddly and requires patience.

If car is idling poorly once warm then its a fuel problem.

dirxnce · Yesterday, 04:59 AM

thanks for the reply mate, my belt just started squealing today too

jaffles · Yesterday, 05:12 AM

Yeh my belt has a little squeak. I have yet to do it but I will. Put a little dishwashing liquid on your finger and try and wipe it onto the pully. Try for the top and bottom and then some on the belt both sides of the pully. Not heaps but make sure its on.

I had a guy at some auto shop tell me that as I could not get my belts to stop squeaking on a 4x4. New belts, proper tight, correct type. Low and behold the squeak went and they don't slip in any way.

04-18-2026, 07:15 AM	#1
dirxnce Registered 0 Rep 2 Posts Drives: 2011 BMW E92 330d Join Date: Mar 2026 Location: Melbourne iTrader: (0)	2011 E92 330d N57, rough idle Hi guys, ive picked up a 161000 kms e92 recently and it has been having a rough idle recently with the rpms fluctuating slightly for a bit before going back to normal. Ive got codes 4A1E, 4A14 and A670. Does this mean I have a failed glow plug and is that the cause of the rough idle. I am new to the N57 engine and dont really know alot about it. thanks
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04-18-2026, 01:09 PM	#2
jaffles Lieutenant 797 Rep 505 Posts Drives: 2010 e93 330d m sport Join Date: Jul 2025 Location: Scenic Rim iTrader: (0)	Glow plugs are for starting, and glow plug controller keeps the plugs glowing while engine is cold until it warms up. Once warm engine should run smooth without both. I imagine checking the resistance on each glow plug will reveal which might be faulty. However 4A1E indicates cylinder 6, closest to firewall. Not sure how to check the glow plug controller, but if the car blows white vapor for a minute or so when starting cold, its a controller. It can be replaced without removing the induction box, but its fiddly and requires patience. If car is idling poorly once warm then its a fuel problem. Last edited by jaffles; 04-18-2026 at 01:17 PM..
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Yesterday, 04:59 AM	#3
dirxnce Registered 0 Rep 2 Posts Drives: 2011 BMW E92 330d Join Date: Mar 2026 Location: Melbourne iTrader: (0)	thanks for the reply mate, my belt just started squealing today too
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Yesterday, 05:12 AM	#4
jaffles Lieutenant 797 Rep 505 Posts Drives: 2010 e93 330d m sport Join Date: Jul 2025 Location: Scenic Rim iTrader: (0)	Yeh my belt has a little squeak. I have yet to do it but I will. Put a little dishwashing liquid on your finger and try and wipe it onto the pully. Try for the top and bottom and then some on the belt both sides of the pully. Not heaps but make sure its on. I had a guy at some auto shop tell me that as I could not get my belts to stop squeaking on a 4x4. New belts, proper tight, correct type. Low and behold the squeak went and they don't slip in any way.
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