Changed Plugs, but running worse

ETexas335 · 05-06-2011, 11:14 AM

Hi all,
My 335i was due for it's 2nd set of plugs (90+K miles) so I bought the Bosch replacement plugs and installed them. The car runs smooth at light throttle, and good at WOT, but there is a certain part throttle spot (like pulling out to pass but not going full throttle) where the car misses and/or runs rough. I can feel the car bucking but if I give it less throttle or push it to the floor it runs fine. My mileage seems to be very slightly less, but I've only checked a tank or two of gas.
I have heard that the ECU has to adapt to the new plugs (with tighter gap, sense the worn plugs gap widens as they wear), but I would have thought it would adjust fairly quickly and not miss that bad at part throttle. Does anyone have any thoughts on this? I have not thrown any codes. Do i need to do a manual ECU reset (pull battery cable)?
I never expected new plugs to affect a car so much, except in a positive way.

Bamaben · 05-06-2011, 01:27 PM

I would like to know if this 'adaption' is true as well. just had mine replaced at dealer and I experience similiar to you just this morning as I was cruising in 2nd changing lanes I felt what was a buck.. However..most of what I'm feeling is the sense of missfire at idle.. it would do this every so often before which I know to be normal but now it is more often and more pronounced. I will going back to dealer soon since they ordered me a new shift boot so when i pick tht up I'm going to ask them about it.

fdriller9 · 05-06-2011, 05:20 PM

There are alot of adaptations on our cars. Lambda (O2 sensors), throttle, octane, knock adaptations are just a few off the top of my head.

You guys should have all the adaptations reset and see if that fixes the problems.

You need a BT scan tool, GT1, Autologic, etc to reset them.

Gregxi · 05-06-2011, 06:19 PM

The ECU does not know or learn about new plugs,air filters,oil or current events.

If you did not have this problem before you changed the plugs I would assume you did something wrong or maybe got a hold of a bad plug.
I would check the plugs again and make sure you did not over torque one of the plugs and crack the porcelain during the install.
Also check the fitment of all the caps/coilsticks

fdriller9 · 05-07-2011, 05:52 PM

But if the plugs were in bad condition upon un-installing them, the car would have altered values to get the most efficient combustion.

If the plugs were causing misfires, the engine will try to adapt to prevent misfires.

When you install new plugs, the car still thinks the car is misfiring, thus the poor performance. It will need time to adapt. Or you can reset the adaptations.

Just my opinion. Don't quote me on any of this.

ETexas335 · 05-09-2011, 11:34 AM

If I have done something like cracked the porcelain or damaged the plug somehow, I would not think it would run well at WOT or idle smoothly. This is rough running in a very narrow range, but I will check out the boots/coils, etc. I torqued everything very carefully to spec, and I thread all plugs by hand (holding the extension of course) to take absolute care not to crossthread them.

It seems to be running better, but I still think I should reset the ECU - I just dont have a BT tool, so I guess I can disconnect the battery?

Blubaron79 · 05-09-2011, 01:03 PM

This sounds goofy, but sometimes newer cars run better on stock plugs. I had this problem with a newer Mitsubishi I owned. The car was missing with top end plugs. My mechanic told me to put in the same brand the car came with; and the car ran great.

Try the same thing with your BMW.

Snow King · 05-09-2011, 05:10 PM

I was doing some research earlier as I'm almost ready to change plugs as well and the advice given was to only replace with OEM plugs. I heard that the Bosch aftermarket plugs may look similar but the specs are not the same.

Dont have any links handy as I'm on the iPhone but run a search.

ETexas335 · 05-09-2011, 05:13 PM

Yep, I saw something earlier on that too - I'll check into it more.

Snow King · 05-10-2011, 02:52 PM

Here are the threads I was looking at

http://www.e90post.com/forums/showth...rk+plugs+Bosch

http://www.e90post.com/forums/showth...rk+plugs+Bosch

Gregxi · 05-10-2011, 05:02 PM

Quote:

Originally Posted by ETexas335

If I have done something like cracked the porcelain or damaged the plug somehow, I would not think it would run well at WOT or idle smoothly. This is rough running in a very narrow range, but I will check out the boots/coils, etc. I torqued everything very carefully to spec, and I thread all plugs by hand (holding the extension of course) to take absolute care not to crossthread them.

It seems to be running better, but I still think I should reset the ECU - I just dont have a BT tool, so I guess I can disconnect the battery?

I was just giving you some things to check, seeing that the problem occured after you performed these repairs, on certain occasions I have seen misfires happen only at heavy acceleration the spark will arc against the wall of the head. Logic would say if it is going to do this it would do it all the time, usually in time it will but in the beginning it might not.

As far as spark plugs go I will never use any other plug than NGK. I have been in the powersports industry for 25 years and have seen nothing but great results from this brand. It is the only brand I would stock or sell.

Kolyan2k · 05-10-2011, 05:33 PM

you cant just buy plugs and install them. need to buy plugs from a dealer for your car. < just in case you bought in autozone or something

ETexas335 · 05-11-2011, 12:00 PM

Quote:

Originally Posted by Gregxi

I was just giving you some things to check, seeing that the problem occured after you performed these repairs, on certain occasions I have seen misfires happen only at heavy acceleration the spark will arc against the wall of the head. Logic would say if it is going to do this it would do it all the time, usually in time it will but in the beginning it might not.

As far as spark plugs go I will never use any other plug than NGK. I have been in the powersports industry for 25 years and have seen nothing but great results from this brand. It is the only brand I would stock or sell.

I appreciate that and I would agree with your logic. It just seemed odd that it runs well at WOT and off idle, but rough only in a particular mid throttle position.

What plugs would use use for our 335i's?

ETexas335 · 05-11-2011, 12:01 PM

I mean specifically what part number NGK...

ETexas335 · 05-11-2011, 12:04 PM

Quote:

Originally Posted by Kolyan2k

you cant just buy plugs and install them. need to buy plugs from a dealer for your car. < just in case you bought in autozone or something

I bought them online from Autohaus.... Bosch OEM - ZGR6STE2.
Is that not the same quality as I would get at the dealer?

ETexas335 · 05-11-2011, 12:17 PM

Quote:

Originally Posted by hchaniar

Here are the threads I was looking at

http://www.e90post.com/forums/showth...rk+plugs+Bosch

http://www.e90post.com/forums/showth...rk+plugs+Bosch

Thanks... I installed the exact same plug that Mr 5 did in that first thread. I assume that is the correct one - same Bosch part number at stock, but different lettering color.

Quisp · 05-11-2011, 12:24 PM

ETexas, when was the last time you had a software update from your dealer?

ETexas335 · 05-11-2011, 12:31 PM

I had the fuel pump replaced last fall, so I think they did it then.

bulldog_yyc · 05-11-2011, 12:44 PM

Quote:

Originally Posted by hchaniar

I was doing some research earlier as I'm almost ready to change plugs as well and the advice given was to only replace with OEM plugs. I heard that the Bosch aftermarket plugs may look similar but the specs are not the same.

Dont have any links handy as I'm on the iPhone but run a search.

same plugs - read the whole thread

05-06-2011, 11:14 AM	#1
ETexas335 Private 8 Rep 84 Posts Drives: 2007 335i Sedan Join Date: May 2010 Location: Texas iTrader: (0)	Changed Plugs, but running worse Hi all, My 335i was due for it's 2nd set of plugs (90+K miles) so I bought the Bosch replacement plugs and installed them. The car runs smooth at light throttle, and good at WOT, but there is a certain part throttle spot (like pulling out to pass but not going full throttle) where the car misses and/or runs rough. I can feel the car bucking but if I give it less throttle or push it to the floor it runs fine. My mileage seems to be very slightly less, but I've only checked a tank or two of gas. I have heard that the ECU has to adapt to the new plugs (with tighter gap, sense the worn plugs gap widens as they wear), but I would have thought it would adjust fairly quickly and not miss that bad at part throttle. Does anyone have any thoughts on this? I have not thrown any codes. Do i need to do a manual ECU reset (pull battery cable)? I never expected new plugs to affect a car so much, except in a positive way.
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05-06-2011, 01:27 PM	#2
Bamaben Major 183 Rep 1,082 Posts Drives: 07 335i blk/blk/alum 6MT Join Date: Jun 2010 Location: Bimmertown iTrader: (0)	I would like to know if this 'adaption' is true as well. just had mine replaced at dealer and I experience similiar to you just this morning as I was cruising in 2nd changing lanes I felt what was a buck.. However..most of what I'm feeling is the sense of missfire at idle.. it would do this every so often before which I know to be normal but now it is more often and more pronounced. I will going back to dealer soon since they ordered me a new shift boot so when i pick tht up I'm going to ask them about it. __________________ It takes a big man to cry. It takes an even bigger man to laugh at him-- Jack Handey mods: blackout grill, finishing rods, badges, Blacklines.
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05-06-2011, 05:20 PM	#3
fdriller9 Banned 255 Rep 7,089 Posts Drives: '06 AW 330xi Join Date: Mar 2009 Location: North Jersey/Philly/NYC iTrader: (4) Garage List 2006 330xi [6.44]	There are alot of adaptations on our cars. Lambda (O2 sensors), throttle, octane, knock adaptations are just a few off the top of my head. You guys should have all the adaptations reset and see if that fixes the problems. You need a BT scan tool, GT1, Autologic, etc to reset them.
	Appreciate 0 Quote

05-06-2011, 06:19 PM	#4
Gregxi First Lieutenant 66 Rep 338 Posts Drives: 2014 535xi Join Date: Feb 2011 Location: MD iTrader: (0)	The ECU does not know or learn about new plugs,air filters,oil or current events. If you did not have this problem before you changed the plugs I would assume you did something wrong or maybe got a hold of a bad plug. I would check the plugs again and make sure you did not over torque one of the plugs and crack the porcelain during the install. Also check the fitment of all the caps/coilsticks
	Appreciate 0 Quote

05-07-2011, 05:52 PM	#5
fdriller9 Banned 255 Rep 7,089 Posts Drives: '06 AW 330xi Join Date: Mar 2009 Location: North Jersey/Philly/NYC iTrader: (4) Garage List 2006 330xi [6.44]	But if the plugs were in bad condition upon un-installing them, the car would have altered values to get the most efficient combustion. If the plugs were causing misfires, the engine will try to adapt to prevent misfires. When you install new plugs, the car still thinks the car is misfiring, thus the poor performance. It will need time to adapt. Or you can reset the adaptations. Just my opinion. Don't quote me on any of this.
	Appreciate 0 Quote

05-09-2011, 11:34 AM	#6
ETexas335 Private 8 Rep 84 Posts Drives: 2007 335i Sedan Join Date: May 2010 Location: Texas iTrader: (0)	If I have done something like cracked the porcelain or damaged the plug somehow, I would not think it would run well at WOT or idle smoothly. This is rough running in a very narrow range, but I will check out the boots/coils, etc. I torqued everything very carefully to spec, and I thread all plugs by hand (holding the extension of course) to take absolute care not to crossthread them. It seems to be running better, but I still think I should reset the ECU - I just dont have a BT tool, so I guess I can disconnect the battery?
	Appreciate 0 Quote

05-09-2011, 01:03 PM	#7
Blubaron79 Brigadier General 1435 Rep 4,724 Posts Drives: 2021 M340i xDrive Join Date: May 2009 Location: PA iTrader: (0)	This sounds goofy, but sometimes newer cars run better on stock plugs. I had this problem with a newer Mitsubishi I owned. The car was missing with top end plugs. My mechanic told me to put in the same brand the car came with; and the car ran great. Try the same thing with your BMW. __________________ Current: 2021 M340i xDrive Previous: '18 340i xDrive; '15 335 xDrive; '14 435i xDrive; '09 335 E92 xDrive
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05-09-2011, 05:10 PM	#8
Snow King Second Lieutenant 18 Rep 270 Posts Drives: 2007 E93 335i Convertible Join Date: Sep 2010 Location: Los Angeles iTrader: (3)	I was doing some research earlier as I'm almost ready to change plugs as well and the advice given was to only replace with OEM plugs. I heard that the Bosch aftermarket plugs may look similar but the specs are not the same. Dont have any links handy as I'm on the iPhone but run a search.
	Appreciate 0 Quote

05-09-2011, 05:13 PM	#9
ETexas335 Private 8 Rep 84 Posts Drives: 2007 335i Sedan Join Date: May 2010 Location: Texas iTrader: (0)	Yep, I saw something earlier on that too - I'll check into it more.
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05-10-2011, 02:52 PM	#10
Snow King Second Lieutenant 18 Rep 270 Posts Drives: 2007 E93 335i Convertible Join Date: Sep 2010 Location: Los Angeles iTrader: (3)	Here are the threads I was looking at http://www.e90post.com/forums/showth...rk+plugs+Bosch http://www.e90post.com/forums/showth...rk+plugs+Bosch
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05-10-2011, 05:33 PM	#12
Kolyan2k Major General 930 Rep 5,538 Posts Drives: 2006 S2000 Join Date: Apr 2010 Location: Boston iTrader: (1)	you cant just buy plugs and install them. need to buy plugs from a dealer for your car. < just in case you bought in autozone or something
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05-11-2011, 12:01 PM	#14
ETexas335 Private 8 Rep 84 Posts Drives: 2007 335i Sedan Join Date: May 2010 Location: Texas iTrader: (0)	I mean specifically what part number NGK...
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05-11-2011, 12:24 PM	#17
Quisp Does not play well with others 80 Rep 1,787 Posts Drives: BMW Join Date: Apr 2007 Location: Arizona iTrader: (4)	ETexas, when was the last time you had a software update from your dealer? __________________
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05-11-2011, 12:31 PM	#18
ETexas335 Private 8 Rep 84 Posts Drives: 2007 335i Sedan Join Date: May 2010 Location: Texas iTrader: (0)	I had the fuel pump replaced last fall, so I think they did it then.
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