2008 335D Slight idle hunting

Westylakey · 03-16-2019, 01:40 PM

The last 2 days when starting my car from cold the idle has bounced slowly between 600-700 for a few seconds, I usually put it in drive pretty quick and move away so don't know how long it lasts. I'm trying to get inpa working but need the files to read my car.
But any ideas on what it might be until I can get it read?
Car is completely standard at the moment at 85k miles.

RL18 · 03-16-2019, 03:07 PM

Mine did something similar to that when I first bought it. Started using an additive when filling up and it completed cured the problem within a couple weeks. Only did it on cold starts though

robnitro · 03-16-2019, 03:20 PM

Get ista-d instead.
Hunting when cold could be a glow plug issue

Westylakey · 03-17-2019, 06:57 AM

thanks for the replies, couldnt get my cable to work so I've ordered a new one which comes with insta-d as well

Xerix · 03-18-2019, 07:07 AM

If the check engine light is on, then scan for codes, you will most likely see a glow plug code or module failing.

If no check engine light is on, then most likely you have carbon buildup and its simply restricting the air. My car had a rough idle as well before i cleaned my intake and runners. But I also had a failed glow plug module that caused similar behaviour below 7 degrees C.

Westylakey · 03-18-2019, 08:27 AM

No check engine light or errors in the idrive menu. Waiting on a new lead to read codes.

richard_tricky · 03-19-2019, 01:35 AM

I get this as well. I have no errors in ista-d. All glow plugs and controller are fine.

Could it be a sensor starting to go? Maf??

Mines a uk car. Intakes look really clean

RL18 · 03-19-2019, 06:31 AM

Honestly if everything checks out good and you say it only happens on cold start it could be something small like fuel quality or fuel filter. Try using and additive in your fuel for the next couple fill ups and change the fuel filter if you haven't. I thought there was a serious injector problem with my D when it was idle searching. And additive should be used in a diesel anyways... diesel isn't refined like gas. Not sure if it the same story for you guys in Europe though

richard_tricky · 03-19-2019, 12:14 PM

I've been using millers additive when filling. I'm guessing a change of the fuel filter is not a bad idea.

My injectors are all new. I swapped them out last year with genuine bosch remanufactured ones.

Ill change the fuel filter.

03-16-2019, 01:40 PM	#1
Westylakey New Member 0 Rep 6 Posts Drives: E92 335D Join Date: Oct 2018 Location: Bristol, UK iTrader: (0)	2008 335D Slight idle hunting The last 2 days when starting my car from cold the idle has bounced slowly between 600-700 for a few seconds, I usually put it in drive pretty quick and move away so don't know how long it lasts. I'm trying to get inpa working but need the files to read my car. But any ideas on what it might be until I can get it read? Car is completely standard at the moment at 85k miles.
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03-16-2019, 03:07 PM	#2
RL18 Major 274 Rep 1,054 Posts Drives: 2011 335d sport Join Date: Nov 2017 Location: Maine iTrader: (0)	Mine did something similar to that when I first bought it. Started using an additive when filling up and it completed cured the problem within a couple weeks. Only did it on cold starts though __________________ 2011 335d tuned by B.R.R. 2011 X5 35d tuned by B.R.R.
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03-16-2019, 03:20 PM	#3
robnitro Captain 160 Rep 803 Posts Drives: x5 35d e70 2011 Join Date: Sep 2016 Location: NYC area iTrader: (0)	Get ista-d instead. Hunting when cold could be a glow plug issue
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03-17-2019, 06:57 AM	#4
Westylakey New Member 0 Rep 6 Posts Drives: E92 335D Join Date: Oct 2018 Location: Bristol, UK iTrader: (0)	thanks for the replies, couldnt get my cable to work so I've ordered a new one which comes with insta-d as well
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03-18-2019, 07:07 AM	#5
Xerix Private First Class 30 Rep 119 Posts Drives: 2010 335d Join Date: Jun 2014 Location: Toronto iTrader: (0)	If the check engine light is on, then scan for codes, you will most likely see a glow plug code or module failing. If no check engine light is on, then most likely you have carbon buildup and its simply restricting the air. My car had a rough idle as well before i cleaned my intake and runners. But I also had a failed glow plug module that caused similar behaviour below 7 degrees C.
	Appreciate 0 Quote

03-18-2019, 08:27 AM	#6
Westylakey New Member 0 Rep 6 Posts Drives: E92 335D Join Date: Oct 2018 Location: Bristol, UK iTrader: (0)	No check engine light or errors in the idrive menu. Waiting on a new lead to read codes.
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03-19-2019, 01:35 AM	#7
richard_tricky Private First Class 16 Rep 140 Posts Drives: 335d Join Date: Feb 2013 Location: Wales iTrader: (0)	I get this as well. I have no errors in ista-d. All glow plugs and controller are fine. Could it be a sensor starting to go? Maf?? Mines a uk car. Intakes look really clean
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03-19-2019, 06:31 AM	#8
RL18 Major 274 Rep 1,054 Posts Drives: 2011 335d sport Join Date: Nov 2017 Location: Maine iTrader: (0)	Honestly if everything checks out good and you say it only happens on cold start it could be something small like fuel quality or fuel filter. Try using and additive in your fuel for the next couple fill ups and change the fuel filter if you haven't. I thought there was a serious injector problem with my D when it was idle searching. And additive should be used in a diesel anyways... diesel isn't refined like gas. Not sure if it the same story for you guys in Europe though __________________ 2011 335d tuned by B.R.R. 2011 X5 35d tuned by B.R.R.
	Appreciate 0 Quote

03-19-2019, 12:14 PM	#9
richard_tricky Private First Class 16 Rep 140 Posts Drives: 335d Join Date: Feb 2013 Location: Wales iTrader: (0)	I've been using millers additive when filling. I'm guessing a change of the fuel filter is not a bad idea. My injectors are all new. I swapped them out last year with genuine bosch remanufactured ones. Ill change the fuel filter.
	Appreciate 0 Quote