Choking at low RPM

Narek · 04-24-2014, 04:32 AM

Hey guys,

My car has developed a problem and as I had no idea, I thought someone here might have some ideas. At low RPMs, (>2000), the car chokes - as if it's running out of petrol - just for a split second (sometimes repetitively). Even at idle, there are choke-like gaps in the exhaust grumble. I'm thinking its nothing severe, as mostly it runs fine. My thoughts were maybe injects, spark plugs, or fuel pump. Used that fuel injector cleaning liquid when I filled up petrol - no luck.

I have some sound coming out of the hood, almost like a whistle. By the sounds of it, I'm thinking its the dynamo. Probably needs calibration. Could the two problems be connected?

I have to honestly point out that I'm not very good at the mechanics of the car.

Thanks in advance.

MDORPHN · 04-24-2014, 08:16 AM

How many miles? What, if any,mods?

Could be something simple like carbon build-up on the intake valves or, perhaps, worn spark plugs.

Neil

ozinaldo · 04-24-2014, 10:31 AM

Quote:

Originally Posted by MDORPHN

How many miles? What, if any,mods?

Could be something simple like carbon build-up on the intake valves or, perhaps, worn spark plugs.

Neil

He has lots of stuff modded:

http://www.1addicts.com/forums/showthread.php?t=974858

Narek · 04-24-2014, 10:49 AM

Milage is just 30k km, so I doubt its something major, especially since there is no power loss or anything of the sort. Just chokes at low rpms. I read about the carbon build-up being a common issue, but is that likely at this level of milage? And if so, how do I clean/get rid of it?

Shooto82 · 04-24-2014, 10:58 AM

Had similer case and it was damaged sparking plug changed by the dealer under warranty . Let us know what the result after getting it checked

Mnime · 04-24-2014, 11:12 AM

Are you having any starting issues?

My car is doing something similar but I am also having occasional starting delays. It will start every time but instead of firing right up the crank turns a few times before it starts. When it does its rough for a second or so then then seems to idle fine. It has never not started though and it is very random. The dealer can not replicate it so they say and no codes are being thrown. Mods for me are N55 mids, Meiserschaft axle back, AFE CAI, ER charge pipe, and Wagner intercooler. Always run 93 oct gas too. Sorry not trying to highjack your thread but the rough idle under 2k happens to me as well so I thought you might have a similar starting issue.

ayao · 04-24-2014, 11:29 AM

Quote:

Originally Posted by Mnime

Are you having any starting issues?

My car is doing something similar but I am also having occasional starting delays. It will start every time but instead of firing right up the crank turns a few times before it starts. When it does its rough for a second or so then then seems to idle fine. It has never not started though and it is very random. The dealer can not replicate it so they say and no codes are being thrown. Mods for me are N55 mids, Meiserschaft axle back, AFE CAI, ER charge pipe, and Wagner intercooler. Always run 93 oct gas too. Sorry not trying to highjack your thread but the rough idle under 2k happens to me as well so I thought you might have a similar starting issue.

This sounds like it could be a HPFP issue ...

Jay-K · 04-24-2014, 12:41 PM

I am pretty sure it is because of the mods.
now i am starting to doubt the n54 1M's durability after modded.
I believe the s65 has better durability than this.

Berra · 04-24-2014, 02:39 PM

Quote:

Originally Posted by Jay-K

I am pretty sure it is because of the mods.
now i am starting to doubt the n54 1M's durability after modded.
I believe the s65 has better durability than this.

What makes you think that?

S65 has more serious issues then the N54, I´m sure you know about the rod bearing problem and also a reason why many have blown motors, both stock and modded ones.

For all we know, his issue can be something simple as spark plugs or a fuel pump.

We all should be aware that more power will wear things faster, that´s just how it is.

Narek · 04-24-2014, 05:19 PM

Quote:

Originally Posted by Berra

What makes you think that?

S65 has more serious issues then the N54, I´m sure you know about the rod bearing problem and also a reason why many have blown motors, both stock and modded ones.

For all we know, his issue can be something simple as spark plugs or a fuel pump.

We all should be aware that more power will wear things faster, that´s just how it is.

Thats precisely what I'm thinking. Just as a precaution I'll just wait till Saturday (Friday off day here) to take it to the garage. Ill post up what they say

Pete_vB · 04-24-2014, 05:41 PM

In most cars one thing I'd be looking for an air leak throwing off your air / fuel ratio. Not sure if the whistle you mention could be something like that?

Mnime · 04-24-2014, 07:21 PM

Quote:

Originally Posted by ayao

Quote:

Originally Posted by Mnime

Are you having any starting issues?

My car is doing something similar but I am also having occasional starting delays. It will start every time but instead of firing right up the crank turns a few times before it starts. When it does its rough for a second or so then then seems to idle fine. It has never not started though and it is very random. The dealer can not replicate it so they say and no codes are being thrown. Mods for me are N55 mids, Meiserschaft axle back, AFE CAI, ER charge pipe, and Wagner intercooler. Always run 93 oct gas too. Sorry not trying to highjack your thread but the rough idle under 2k happens to me as well so I thought you might have a similar starting issue.

This sounds like it could be a HPFP issue ...

I don't like that answer

but unfortunately that is what I was thinking as well.
I would think the dealer would have been able to check that somehow?

Jay-K · 04-24-2014, 08:13 PM

Quote:

Originally Posted by Berra

What makes you think that?

S65 has more serious issues then the N54, I´m sure you know about the rod bearing problem and also a reason why many have blown motors, both stock and modded ones.

For all we know, his issue can be something simple as spark plugs or a fuel pump.

We all should be aware that more power will wear things faster, that´s just how it is.

from the experience i had with it.
I agree that more power will increase the tear and wear of an engine, also requires a more frequent maintenance needed to be done.
Check the intake box as well if it has leak, that's what the dealer mainly say about 1M's problems.

mike@x-ph.com · 04-24-2014, 09:32 PM

Post a log

Narek · 04-26-2014, 10:20 AM

From what I gathered after the initial test drive, its an injector issue. More news soon to come.

Narek · 04-27-2014, 03:13 PM

Regarding the choking, still no update. However, some of the noise is from the diff (upgraded quaiffe diff, but still excessive noise for helical). Investigating into that. The choking first guess by the mechs is that its injectors, which they can repair rather than replace. They'll check out the HPFP just in case. Another major issue is the ECU tune - manhart didn't do a very good job. As I said in my into post, the numbers given to me were unsupported - once the diff and choking issues are done the car is going directly onto dyno, just for reference, followed by a detune to stock ecu. Now I'm thinking instead of the detune, to order Cobb, and have an etune via PTF or HPF.

Any advice as to which of the two is a better etune? or any compelling argument (other than price) to go for a JB4?

04-24-2014, 04:32 AM	#1
Narek Newbie 6 Rep 68 Posts Drives: AW 1M (MH1 S) Join Date: Apr 2014 Location: Dubai iTrader: (0)	Choking at low RPM Hey guys, My car has developed a problem and as I had no idea, I thought someone here might have some ideas. At low RPMs, (>2000), the car chokes - as if it's running out of petrol - just for a split second (sometimes repetitively). Even at idle, there are choke-like gaps in the exhaust grumble. I'm thinking its nothing severe, as mostly it runs fine. My thoughts were maybe injects, spark plugs, or fuel pump. Used that fuel injector cleaning liquid when I filled up petrol - no luck. I have some sound coming out of the hood, almost like a whistle. By the sounds of it, I'm thinking its the dynamo. Probably needs calibration. Could the two problems be connected? I have to honestly point out that I'm not very good at the mechanics of the car. Thanks in advance.
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04-24-2014, 08:16 AM	#2
MDORPHN Colonel 291 Rep 2,898 Posts Drives: AW 1M Join Date: Oct 2010 Location: Wash, DC iTrader: (0)	How many miles? What, if any,mods? Could be something simple like carbon build-up on the intake valves or, perhaps, worn spark plugs. Neil
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04-24-2014, 10:49 AM	#4
Narek Newbie 6 Rep 68 Posts Drives: AW 1M (MH1 S) Join Date: Apr 2014 Location: Dubai iTrader: (0)	Milage is just 30k km, so I doubt its something major, especially since there is no power loss or anything of the sort. Just chokes at low rpms. I read about the carbon build-up being a common issue, but is that likely at this level of milage? And if so, how do I clean/get rid of it?
	Appreciate 0 Quote

04-24-2014, 10:58 AM	#5
Shooto82 Private 22 Rep 85 Posts Drives: BMW 1m Join Date: Aug 2012 Location: Bahrain iTrader: (0)	Had similer case and it was damaged sparking plug changed by the dealer under warranty . Let us know what the result after getting it checked
	Appreciate 0 Quote

04-24-2014, 11:12 AM	#6
Mnime First Lieutenant 24 Rep 391 Posts Drives: 2015 Cayman GTS Join Date: Jan 2011 Location: Dallas, TX USA iTrader: (0)	Are you having any starting issues? My car is doing something similar but I am also having occasional starting delays. It will start every time but instead of firing right up the crank turns a few times before it starts. When it does its rough for a second or so then then seems to idle fine. It has never not started though and it is very random. The dealer can not replicate it so they say and no codes are being thrown. Mods for me are N55 mids, Meiserschaft axle back, AFE CAI, ER charge pipe, and Wagner intercooler. Always run 93 oct gas too. Sorry not trying to highjack your thread but the rough idle under 2k happens to me as well so I thought you might have a similar starting issue. __________________ Current - 2015 Cayman GTS White Borla Exhaust Prev - AW 1M #43 USA Meisterschaft, N55 mids, AFE CAI, ER Charge, Wagner IC
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04-24-2014, 12:41 PM	#8
Jay-K Brigadier General 384 Rep 3,450 Posts Drives: Slow Join Date: Nov 2011 Location: LA iTrader: (0)	I am pretty sure it is because of the mods. now i am starting to doubt the n54 1M's durability after modded. I believe the s65 has better durability than this. __________________ "Well, there's a straight-six engine at the front, a manual gearbox in the middle and drive goes to the back. That's Page 1, Chapter 1 from the petrosexual handbook" - JC
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04-24-2014, 05:41 PM	#11
Pete_vB Captain 118 Rep 898 Posts Drives: '69 GT3, GT4, 1M, 912 Join Date: Nov 2010 Location: SF Bay Area, Shenzhen, Oman iTrader: (0)	In most cars one thing I'd be looking for an air leak throwing off your air / fuel ratio. Not sure if the whistle you mention could be something like that? __________________ 1M, GT4, 1969 Porsche 911 w/ 997 GT3 Cup Motor (435hp & 2,100 lbs)
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04-24-2014, 09:32 PM	#14
mike@x-ph.com Joint Chiefs of Staff 24095 Rep 190,633 Posts Drives: 07-335/12-328/18-M4/21-M4CP Join Date: Sep 2013 Location: Las Vegas iTrader: (23)	Post a log __________________ Check out our current sale by clicking on this link! https://x-ph.com/sale/ Phone number 702-494-9435
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04-26-2014, 10:20 AM	#15
Narek Newbie 6 Rep 68 Posts Drives: AW 1M (MH1 S) Join Date: Apr 2014 Location: Dubai iTrader: (0)	From what I gathered after the initial test drive, its an injector issue. More news soon to come.
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04-27-2014, 03:13 PM	#16
Narek Newbie 6 Rep 68 Posts Drives: AW 1M (MH1 S) Join Date: Apr 2014 Location: Dubai iTrader: (0)	Regarding the choking, still no update. However, some of the noise is from the diff (upgraded quaiffe diff, but still excessive noise for helical). Investigating into that. The choking first guess by the mechs is that its injectors, which they can repair rather than replace. They'll check out the HPFP just in case. Another major issue is the ECU tune - manhart didn't do a very good job. As I said in my into post, the numbers given to me were unsupported - once the diff and choking issues are done the car is going directly onto dyno, just for reference, followed by a detune to stock ecu. Now I'm thinking instead of the detune, to order Cobb, and have an etune via PTF or HPF. Any advice as to which of the two is a better etune? or any compelling argument (other than price) to go for a JB4?
	Appreciate 0 Quote