Jerky/Stuttery acceleration after initial cold start

7smurfs · 03-02-2015, 03:15 AM

When I initially start the car after sitting for 5-10 hours cold it will experience experience extremely jerky acceleration like power is constantly being cut until about 3-5km into the journey in which everything returns back to normal.

No codes are being thrown...

Stats on car:
jb4 latest firmware
n54 MT
DCI
axleback exhaust

The strange thing is that after it has been driven to the warm up point, the car will not return back to the stuttery acceleration state for the day until it has sat for 5 hours +

My current thoughts on what might be causing the issue are:
- Fuel pump
- Carbon build up
- Injectors
- Coils
- JB4 firmware issue

Has anyone experienced something similar or know what's up?

BMW86 · 03-02-2015, 03:32 AM

How many km's on your car and what have you replaced so far?

DR-JEKL · 03-02-2015, 03:42 AM

Maybe try some fresh plugs?

I had bought my car with a full bmw service done with new plugs and 6 months later had stuttery jerking at low revs going around corners etc in 2nd gear.

Changed coils it improved, but was still there and my plugs had only done 2-3k kays use, but decided to bite the bullet and change them as i didnt trust the dealer.

When i removed the plugs they did look newish, so the dealer had changed them... so i swapped them over anyway and bang my car was a lot better, it felt so much stronger at low revs

(no idea what was wrong with the plugs)

Also I ended up swapping over vanos solenoids and pre cat 02 sensors and that really helped eliminate any jerkiness completely and it finally drove how a bmw car should!

7smurfs · 03-02-2015, 03:58 AM

My car has done 56,000km with oil service done every 7000km.
From my knowledge, still on original injectors/fuel pump/water pump though mine is MY2010 N54 so hopefully had the latest gear in it.

2 months ago did oil change
6 months did 1 coil change (to fix misfire) and full plugs change.

Hmm... will try plugs, though they should be basically new

Strangely the car drives totally fine after 3-5kms

Ott74 · 03-03-2015, 02:22 AM

Charge pipe?

Weezy · 03-03-2015, 02:49 AM

Surprised your ECU is pulling codes?

DR-JEKL · 03-03-2015, 06:54 AM

Quote:

Originally Posted by 7smurfs

My car has done 56,000km with oil service done every 7000km.
From my knowledge, still on original injectors/fuel pump/water pump though mine is MY2010 N54 so hopefully had the latest gear in it.

2 months ago did oil change
6 months did 1 coil change (to fix misfire) and full plugs change.

Hmm... will try plugs, though they should be basically new

Strangely the car drives totally fine after 3-5kms

do you ever have a fuel odour? Does it blow any smoke on startup at all? (injector failure symptoms)

MightyMouseTech · 03-03-2015, 07:03 AM

I had something very similar, turns out the plugs that came with the PPK kit are the wrong plugs for my N55 motor. Changed to a new set of plugs, runs perfect again.

TS135i · 03-03-2015, 12:10 PM

Quote:

Originally Posted by MightyMouseTech

I had something very similar, turns out the plugs that came with the PPK kit are the wrong plugs for my N55 motor. Changed to a new set of plugs, runs perfect again.

Are plugs part of the PPK kit?

MightyMouseTech · 03-03-2015, 12:21 PM

Quote:

Originally Posted by TS135i

Are plugs part of the PPK kit?

I bought the PPK2 kit, and yes, a new set of plugs came with it. Problem is, the kit came with the wrong ones, they were the plugs for an N54, which will not work in the N55.

7smurfs · 03-03-2015, 10:35 PM

Quote:

Originally Posted by Ott74

Charge pipe?

I'm not sure if it is this. Not sure how to check

Quote:

Originally Posted by Weezy

Surprised your ECU is pulling codes?

Yeah no codes thus far.

Quote:

Originally Posted by DR-JEKL

do you ever have a fuel odour? Does it blow any smoke on startup at all? (injector failure symptoms)

Will have a sniff later!

racer_x · 03-03-2015, 10:54 PM

Plugs sound like the cheapest place to start. Especially if they are the original plugs and you're running a tune.

7smurfs · 03-04-2015, 05:55 PM

Quote:

Originally Posted by racer_x

Plugs sound like the cheapest place to start. Especially if they are the original plugs and you're running a tune.

Plugs were changed about 3-5 months ago though

froop · 03-04-2015, 10:30 PM

I had this issue. I thought it was injectors as I was getting stumbling during cold starts and also stumbling during low rpm acceleration. High rpm WOT was fine. It went away completely by itself though so now I have no idea what it was...

7smurfs · 03-04-2015, 11:10 PM

Quote:

Originally Posted by froop

I had this issue. I thought it was injectors as I was getting stumbling during cold starts and also stumbling during low rpm acceleration. High rpm WOT was fine. It went away completely by itself though so now I have no idea what it was...

Damn!

I have a feeling it's carbon build up related. Maybe I gotta give the car a bit of high rpm WOT to clean it out hmmm.....

I'm usually shifting at a max of 4000-5000rpm since the car hits the speed limit so damn quick if i go 6000+

DR-JEKL · 03-05-2015, 08:40 PM

Quote:

Originally Posted by 7smurfs

Damn!

I have a feeling it's carbon build up related. Maybe I gotta give the car a bit of high rpm WOT to clean it out hmmm.....

I'm usually shifting at a max of 4000-5000rpm since the car hits the speed limit so damn quick if i go 6000+

Maybe run some liqui moly injector/fuel system cleaner and see what happens?

ExREX · 03-06-2015, 09:01 PM

Quote:

Originally Posted by froop

I had this issue. I thought it was injectors as I was getting stumbling during cold starts and also stumbling during low rpm acceleration. High rpm WOT was fine. It went away completely by itself though so now I have no idea what it was...

I had this problem, came and went over time especially in winter. Finally was consistent and was diagnosed as 4 fuel injectors. I had all 6 changed.

7smurfs · 03-08-2015, 08:37 PM

Quote:

Originally Posted by ExREX

I had this problem, came and went over time especially in winter. Finally was consistent and was diagnosed as 4 fuel injectors. I had all 6 changed.

Interesting... mine seems to have gone now for some odd reason.

Might be after I went hard WOT on the car

totti84 · 03-08-2015, 09:55 PM

I've also had this problem (I had multiple misfire cyl# codes)

I bought new OEM injectors and the problem disappeared before I got around to installing the injectors

7smurfs · 03-08-2015, 10:30 PM

Damn pulled a code immediately after cold start today:
29E0 fuel mixture control

Looks like o2 sensors or fuel injectors dying

n54 is one hell of a strange motor

1_dez · 03-31-2015, 05:05 AM

I experienced the same issue this week (rough idle, almost stalling and loss of accelerating power in the morning, generally in cooler ~10*c weather).

BMW verified my concern and found that my car was misfiring when cold. They found that one of my coils (cyl 4) was faulty and that the car was registering other "varying cylinder faults".

Replaced all coils and all spark plugs. Problem solved, car feels much more healthier.

Plugs were ~$180 and Coils were ~$500 (with 2 yr warranty).

Engine is completely stock.

GL finding your issue. Hope this helps.

7smurfs · 03-31-2015, 07:41 PM

Quote:

Originally Posted by 1_dez

I experienced the same issue this week (rough idle, almost stalling and loss of accelerating power in the morning, generally in cooler ~10*c weather).

BMW verified my concern and found that my car was misfiring when cold. They found that one of my coils (cyl 4) was faulty and that the car was registering other "varying cylinder faults".

Replaced all coils and all spark plugs. Problem solved, car feels much more healthier.

Plugs were ~$180 and Coils were ~$500 (with 2 yr warranty).

Engine is completely stock.

GL finding your issue. Hope this helps.

Interesting! Did you get any codes?

Mine seems to be running fine now, without any sputtering and then it randomly pops a Fuel mixture control code

I have a feeling it is a leaky injector which i got quoted $900 to fix just one....... will try some cheaper alternatives such as coils beforehand.

Where did you get your coils from?!

03-02-2015, 03:15 AM	#1
7smurfs Captain 137 Rep 902 Posts Drives: M3 CS Join Date: Apr 2014 Location: Melbourne iTrader: (0)	Jerky/Stuttery acceleration after initial cold start When I initially start the car after sitting for 5-10 hours cold it will experience experience extremely jerky acceleration like power is constantly being cut until about 3-5km into the journey in which everything returns back to normal. No codes are being thrown... Stats on car: jb4 latest firmware n54 MT DCI axleback exhaust The strange thing is that after it has been driven to the warm up point, the car will not return back to the stuttery acceleration state for the day until it has sat for 5 hours + My current thoughts on what might be causing the issue are: - Fuel pump - Carbon build up - Injectors - Coils - JB4 firmware issue Has anyone experienced something similar or know what's up?
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03-02-2015, 03:32 AM	#2
BMW86 Major General 398 Rep 9,156 Posts Drives: RS3 Sedan / Macan S Join Date: Jul 2008 Location: Australia iTrader: (0)	How many km's on your car and what have you replaced so far?
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03-02-2015, 03:42 AM	#3
DR-JEKL Major General 898 Rep 6,285 Posts Drives: Space Grey E92 335i 6MT Join Date: Jul 2012 Location: Newcastle Ozstraylia iTrader: (3)	Maybe try some fresh plugs? I had bought my car with a full bmw service done with new plugs and 6 months later had stuttery jerking at low revs going around corners etc in 2nd gear. Changed coils it improved, but was still there and my plugs had only done 2-3k kays use, but decided to bite the bullet and change them as i didnt trust the dealer. When i removed the plugs they did look newish, so the dealer had changed them... so i swapped them over anyway and bang my car was a lot better, it felt so much stronger at low revs (no idea what was wrong with the plugs) Also I ended up swapping over vanos solenoids and pre cat 02 sensors and that really helped eliminate any jerkiness completely and it finally drove how a bmw car should!
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03-02-2015, 03:58 AM	#4
7smurfs Captain 137 Rep 902 Posts Drives: M3 CS Join Date: Apr 2014 Location: Melbourne iTrader: (0)	My car has done 56,000km with oil service done every 7000km. From my knowledge, still on original injectors/fuel pump/water pump though mine is MY2010 N54 so hopefully had the latest gear in it. 2 months ago did oil change 6 months did 1 coil change (to fix misfire) and full plugs change. Hmm... will try plugs, though they should be basically new Strangely the car drives totally fine after 3-5kms
	Appreciate 0 Quote

03-03-2015, 02:22 AM	#5
Ott74 New Member 0 Rep 19 Posts Drives: BMW 135I MY09 Join Date: May 2014 Location: Melbourne iTrader: (0)	Charge pipe?
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03-03-2015, 02:49 AM	#6
Weezy Private First Class 11 Rep 110 Posts Drives: 2008 E82 135i Join Date: Mar 2014 Location: Adelaide, South Australia iTrader: (0)	Surprised your ECU is pulling codes?
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03-03-2015, 07:03 AM	#8
MightyMouseTech Major General 4338 Rep 6,196 Posts Drives: 13 135i 6MT LeMans Blue MSport Join Date: Feb 2013 Location: Ottawa, Canada iTrader: (0)	I had something very similar, turns out the plugs that came with the PPK kit are the wrong plugs for my N55 motor. Changed to a new set of plugs, runs perfect again.
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03-03-2015, 10:54 PM	#12
racer_x Second Lieutenant 13 Rep 226 Posts Drives: When He Has To Join Date: Jan 2013 Location: Sydney iTrader: (0)	Plugs sound like the cheapest place to start. Especially if they are the original plugs and you're running a tune.
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03-04-2015, 10:30 PM	#14
froop Colonel 171 Rep 2,682 Posts Drives: 08 AW 6MT E82 Join Date: Jul 2012 Location: Sydney, Australia iTrader: (3)	I had this issue. I thought it was injectors as I was getting stumbling during cold starts and also stumbling during low rpm acceleration. High rpm WOT was fine. It went away completely by itself though so now I have no idea what it was... __________________ froop's AW 135i Build Thread
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03-08-2015, 09:55 PM	#19
totti84 Major 112 Rep 1,140 Posts Drives: N54 135i 6MT Join Date: Aug 2014 Location: Sydney, Australia iTrader: (5) Garage List 2009 BMW 135i M Sport [0.00]	I've also had this problem (I had multiple misfire cyl# codes) I bought new OEM injectors and the problem disappeared before I got around to installing the injectors
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03-08-2015, 10:30 PM	#20
7smurfs Captain 137 Rep 902 Posts Drives: M3 CS Join Date: Apr 2014 Location: Melbourne iTrader: (0)	Damn pulled a code immediately after cold start today: 29E0 fuel mixture control Looks like o2 sensors or fuel injectors dying n54 is one hell of a strange motor
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03-31-2015, 05:05 AM	#21
1_dez Private 4 Rep 94 Posts Drives: 1er Join Date: Jun 2012 Location: Vic iTrader: (0)	I experienced the same issue this week (rough idle, almost stalling and loss of accelerating power in the morning, generally in cooler ~10*c weather). BMW verified my concern and found that my car was misfiring when cold. They found that one of my coils (cyl 4) was faulty and that the car was registering other "varying cylinder faults". Replaced all coils and all spark plugs. Problem solved, car feels much more healthier. Plugs were ~$180 and Coils were ~$500 (with 2 yr warranty). Engine is completely stock. GL finding your issue. Hope this helps.
	Appreciate 0 Quote