E90 318d Rough from Cold / lumpy part throttle

chadvandonkey · 12-09-2014, 03:44 AM

I've had this problem since last winter and it only appears during cold starting. Car cranks and fires straight away but then has a lumpy idle like a misfire. If you gently rev it for a couple of seconds this clears and it idles normally. It was like this all last year and I never worried because it cleared.

This morning it did the same, cleared and seemed fine but then a few miles down the road it was running in the same lumpy state on initial throttle opening. Idle was fine, engine on load was fine but just the tiniest amount of throttle and it felt like it was misfiring (same as the lumpy idle).

I've read about glow plugs being the culprit and they may well be. Same for the control unit which may be at fault. Also swirl flap actuator being to blame - what is this and can it be checked? Some folk suggest fuel but I'm sure this has zero bearing on this.

Luckily I have a local BMW specialist that I will take the car too but I'd like to know about it so I don't get fleeced.

Any help / thoughts would be appreciated.

borinous · 12-09-2014, 04:02 AM

Mine does the same minus the lumpy part throttle (or at least not that ive noticed) i read the fault codes which gave all 4 glow plugs as the fault. From reading on here its more than likely just the control unit. I have one to go on but it seems to be easier to fit from underneath so waiting for some ramp time to come available.

Just ask your specialist to read the error codes for you that will shed some light on the issue for you

chadvandonkey · 12-09-2014, 04:12 AM

For the price I'm tempted to just replace the Control Unit. Where is it located and how do you perform the job?

borinous · 12-09-2014, 05:24 AM

found this guide for 320d its for a e46 but i would guess they are in the same or very simular place

http://www.bmwforums.info/3-series-g...tud20-diy.html

theres a few other guide online if you do some digging

Sensible_ · 12-09-2014, 07:07 AM

If it's an N47 engine I think you might be able to get to it from under the bonnet, if you have small hands. It's attached to inlet manifold at a weird angle if I remember correctly.

chadvandonkey · 12-11-2014, 03:55 AM

Quote:

Originally Posted by Sensible_

If it's an N47 engine I think you might be able to get to it from under the bonnet, if you have small hands. It's attached to inlet manifold at a weird angle if I remember correctly.

I've tried to find a guide of some sort to show where and how to replace but without any luck so far - does anyone know of a decent guide?

will1968 · 12-11-2014, 07:57 AM

I had this on my 320d for a long time on cold start then it caused running problems when warn like hesitation on part throttle and lumpy idle.
Had just the glow plugs replaced not the control module and been fine now for the last 18 months and 30K.
The glow plugs were about £12 each and local garage fitted them for £90.

12-09-2014, 03:44 AM	#1
chadvandonkey New Member 6 Rep 17 Posts Drives: BMW 318d M Sport Join Date: Aug 2011 Location: Nottinghamshire iTrader: (0)	E90 318d Rough from Cold / lumpy part throttle I've had this problem since last winter and it only appears during cold starting. Car cranks and fires straight away but then has a lumpy idle like a misfire. If you gently rev it for a couple of seconds this clears and it idles normally. It was like this all last year and I never worried because it cleared. This morning it did the same, cleared and seemed fine but then a few miles down the road it was running in the same lumpy state on initial throttle opening. Idle was fine, engine on load was fine but just the tiniest amount of throttle and it felt like it was misfiring (same as the lumpy idle). I've read about glow plugs being the culprit and they may well be. Same for the control unit which may be at fault. Also swirl flap actuator being to blame - what is this and can it be checked? Some folk suggest fuel but I'm sure this has zero bearing on this. Luckily I have a local BMW specialist that I will take the car too but I'd like to know about it so I don't get fleeced. Any help / thoughts would be appreciated. Last edited by chadvandonkey; 12-09-2014 at 04:09 AM..
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12-09-2014, 04:02 AM	#2
borinous Captain 39 Rep 686 Posts Drives: E90 320d SE Join Date: Sep 2014 Location: Essex iTrader: (2)	Mine does the same minus the lumpy part throttle (or at least not that ive noticed) i read the fault codes which gave all 4 glow plugs as the fault. From reading on here its more than likely just the control unit. I have one to go on but it seems to be easier to fit from underneath so waiting for some ramp time to come available. Just ask your specialist to read the error codes for you that will shed some light on the issue for you
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12-09-2014, 04:12 AM	#3
chadvandonkey New Member 6 Rep 17 Posts Drives: BMW 318d M Sport Join Date: Aug 2011 Location: Nottinghamshire iTrader: (0)	For the price I'm tempted to just replace the Control Unit. Where is it located and how do you perform the job?
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12-09-2014, 05:24 AM	#4
borinous Captain 39 Rep 686 Posts Drives: E90 320d SE Join Date: Sep 2014 Location: Essex iTrader: (2)	found this guide for 320d its for a e46 but i would guess they are in the same or very simular place http://www.bmwforums.info/3-series-g...tud20-diy.html theres a few other guide online if you do some digging
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12-09-2014, 07:07 AM	#5
Sensible_ Colonel 532 Rep 2,503 Posts Drives: 2008 E90 Join Date: Feb 2012 Location: London iTrader: (1)	If it's an N47 engine I think you might be able to get to it from under the bonnet, if you have small hands. It's attached to inlet manifold at a weird angle if I remember correctly.
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12-11-2014, 07:57 AM	#7
will1968 Private First Class 8 Rep 158 Posts Drives: F32 Join Date: Oct 2008 Location: UK iTrader: (4)	I had this on my 320d for a long time on cold start then it caused running problems when warn like hesitation on part throttle and lumpy idle. Had just the glow plugs replaced not the control module and been fine now for the last 18 months and 30K. The glow plugs were about £12 each and local garage fitted them for £90.
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