N55 AT pulsating/throbbing at idle

xxMike61 · 11-08-2017, 08:07 PM

So about three months ago i installed a vrsf dp on my N55 AT. Install was pretty doable thanks to a lift. Pretty sure I did everything correctly as its difficult to mix up the two o2 sensors. However when idling the car feels like it is jumping up and down 20-30 rpms even when warmed up.

Logs show just what I thought. When monitoring, the rpm bounces between a range of 20-30 rpms. New coils and plugs around the same time. Any thoughts?

Mods are : BMS intake, BMS CP, VRSF DP, ARM FMIC, muffler delete, stage 1 MHD, stage 3 xHP.

yayaya · 11-09-2017, 08:30 AM

Quote:

Originally Posted by xxMike61

So about three months ago i installed a vrsf dp on my N55 AT. Install was pretty doable thanks to a lift. Pretty sure I did everything correctly as its difficult to mix up the two o2 sensors. However when idling the car feels like it is jumping up and down 20-30 rpms even when warmed up.

Logs show just what I thought. When monitoring, the rpm bounces between a range of 20-30 rpms. New coils and plugs around the same time. Any thoughts?

Mods are : BMS intake, BMS CP, VRSF DP, ARM FMIC, muffler delete, stage 1 MHD, stage 3 xHP.

Interested in an answer to this as well. Have an 11' 335xi same mods except stock air box and mufflers and experience this as well. I've noticed that when the car is jumping if I turn the car on and off twice the jumping goes away but usually returns the next drive. Hopefully someone can give us some insight into this issue.

weehe126 · 11-09-2017, 09:18 AM

I've been dealing with this ever wince I installed my vrsf dp as well, 50k miles ago. I've got a new O2 sensor to put in to see if it fixes it. I think it just happens to some cars when going catless.

AJL · 11-09-2017, 01:00 PM

I have similar idle fluctuations. At this point it's been happening for so long that I'm not sure if it started right when the DP was installed, or a little while after that.

Coils and plugs were replaced around the same time.
Exhaust shop confirmed there was no leak after installing.
VRSF Downpipe, FMIC, ER CP, MHD Stage 2+ (93 Oct), Xhp Stage 3, K&N Drop-in.

My car has been seeing lots of timing corrections lately, so I'm changing the plugs this weekend, I'll also be cleaning the MAF to see if that helps at all with this specific issue.

I was very careful during the original install to make sure that the O2 sensors went back in the correct places (I mean, there's only 2..), so I highly doubt that's the issue. However I suppose it's possible that one of the sensors was damaged during the install, but if I have any luck solving the issue, I'll let ya'll know. For right now, it's really not that big of a deal since the car runs perfectly otherwise.

Turbod · 11-09-2017, 01:01 PM

I had/have two different issues with the 335i. The first one was with the JB4 the wastegate setting needed to be adjusted because it would pulsate under load. I would be climbing a hill and you could hear the pulse through the exhaust.

The one I still currently deal with is inconsistent idle when turning the car at low speeds or in reverse. I always just assumed it was due to the load of the power steering pump.

FireBlaze · 11-09-2017, 01:46 PM

I have this issue too. Barely noticeable but its there... Still trying to figure it out but something i can definitely live with it as long is it doesn't hurt the car.

xxMike61 · 11-09-2017, 03:02 PM

Yeah I am also having crazy pulses when in turning in reverse and drive on low throttle. Very weird. Happened before I modded anything

NRigs · 11-09-2017, 03:09 PM

Quote:

Originally Posted by xxMike61

Yeah I am also having crazy pulses when in turning in reverse and drive on low throttle. Very weird. Happened before I modded anything

Same here. Seems like it is just a #335Problem

rich_mane · 11-09-2017, 06:53 PM

I'm pretty sure BMW even had a bulletin about the idle fluctuating at low speeds or turning. Was a pretty common problem that they supposedly solved with DME programming... Maybe raised the idle slightly or something

Mean E92 · 11-09-2017, 08:00 PM

Yeah I have the same issue. I noticed it after installing the dp which is catless. So the N55 must be very sensitive to no cat.

RickySATX · 11-09-2017, 11:41 PM

I've had idle issues for as long as I can remember, even when I was all stock. PPK flashed help some and got rid of the stalling for the most part. Now I'm FBO w/MHD and when coming to a stop RPMs drop to at or below 500 and continue to bounce around at idle. Sometimes fluctuations vary from 500 rpm to 900 rpm. It's stupid annoying but I've come to realize this is just a quick with this car. I think rpm adjustment via MHD would help this issue but I don't see them addressing this anytime soon.

Joe@TopGearSolutions · 11-14-2017, 08:17 AM

Quote:

Originally Posted by RickySATX

I've had idle issues for as long as I can remember, even when I was all stock. PPK flashed help some and got rid of the stalling for the most part. Now I'm FBO w/MHD and when coming to a stop RPMs drop to at or below 500 and continue to bounce around at idle. Sometimes fluctuations vary from 500 rpm to 900 rpm. It's stupid annoying but I've come to realize this is just a quick with this car. I think rpm adjustment via MHD would help this issue but I don't see them addressing this anytime soon.

Do you know software or DATEN version of the PPK you have? There's a possibility you have a slightly older one (should start with 868***).

E46toE90 · 11-16-2017, 09:25 PM

What are the chances of it being due to the pcv valve in valve cover? My n55 also does idle surges. There was a time I did oil change and forgot to tighten oil cap my idle surge was insane I had to pull over and check. My pcv went bad so seals were howling once you pull oil cap noise goes away. So what are the chances of when I do valve cover idle surges go away? Let you guys know Sunday!!!

AJL · 11-16-2017, 09:53 PM

Quote:

Originally Posted by E46toE90

What are the chances of it being due to the pcv valve in valve cover? My n55 also does idle surges. There was a time I did oil change and forgot to tighten oil cap my idle surge was insane I had to pull over and check. My pcv went bad so seals were howling once you pull oil cap noise goes away. So what are the chances of when I do valve cover idle surges go away? Let you guys know Sunday!!!

I just changed my valve cover maybe 2-3k miles ago, it helped with idle surging a bit at lights when coming to a stop, but not with the very slight fluctuations when idling normally. I do get some pretty large surges when reversing still as well.

Mean E92 · 11-16-2017, 11:28 PM

I still have it even after getting a new VC, thinking it was my PCV valve. I honestly think it has to do with catless dps. Or something VANOS related. These cars are so complicated to the point were it's almost impossible to diagnose something.

Boo$ted_in_ri · 11-27-2017, 09:51 PM

My car does this every morning when I leave for work. I’m just always ready for it now. I get pretty pissed when I’m pulling into a parking spot and it jumps forward quick on me tho! Lol

OneMoreAlex · 11-28-2017, 10:49 AM

Not saying this will solve your problem, but I had the same thing happen. I tried chasing it down for months and finally seemed to find where it's coming from.

Finally what seemed to fix my issue was when I switched back to my factory air intake instead of running the BMS intake. Haven't had this problem once since.

bcaz808 · 11-28-2017, 11:08 AM

Quote:

Originally Posted by OneMoreAlex

Not saying this will solve your problem, but I had the same thing happen. I tried chasing it down for months and finally seemed to find where it's coming from.

Finally what seemed to fix my issue was when I switched back to my factory air intake instead of running the BMS intake. Haven't had this problem once since.

I bet the MAF just needs to be re scaled for the BMS intake.

Mean E92 · 12-02-2017, 10:12 AM

Quote:

Originally Posted by bcaz808

I bet the MAF just needs to be re scaled for the BMS intake.

I took my BMS intake off and I use a different one now. It does this issue less. But I bet if I use the stock intake the idle would be perfect. The BMS intake has lots of issues.

weehe126 · 12-02-2017, 11:29 AM

I had the issue with the stock intake and it didn't change when I put the BMS intake on. I've noticed when my oil level is closer to +1qt, it gets worse. If I keep my oil level at max it almost stops completely. So I believe it has to do with the vanos solenoids and oil pressure.

MiamiM3 · 12-02-2017, 10:32 PM

I also have the rpm surging from 500 to 900 rpms when the car is in reverse or when making tight turns into parking spots. I have stock intake with K&N drop in filter. I am at a total loss with this issue and it is driving me crazy.

Mean E92 · 12-03-2017, 12:31 AM

Quote:

Originally Posted by weehe126

I had the issue with the stock intake and it didn't change when I put the BMS intake on. I've noticed when my oil level is closer to +1qt, it gets worse. If I keep my oil level at max it almost stops completely. So I believe it has to do with the vanos solenoids and oil pressure.

The issue is I can't tell if I'm close to +1qt or not.

11-08-2017, 08:07 PM	#1
xxMike61 First Lieutenant 78 Rep 239 Posts Drives: 2011 335i Coupe Join Date: Feb 2017 Location: Sacramento, CA iTrader: (0)	N55 AT pulsating/throbbing at idle So about three months ago i installed a vrsf dp on my N55 AT. Install was pretty doable thanks to a lift. Pretty sure I did everything correctly as its difficult to mix up the two o2 sensors. However when idling the car feels like it is jumping up and down 20-30 rpms even when warmed up. Logs show just what I thought. When monitoring, the rpm bounces between a range of 20-30 rpms. New coils and plugs around the same time. Any thoughts? Mods are : BMS intake, BMS CP, VRSF DP, ARM FMIC, muffler delete, stage 1 MHD, stage 3 xHP. __________________ 2011 335i M-Sport E92 MHD E30 \| Phoenix Racing CP \| K&N Drop In Air Filter \|Fuel-it Stage 2 LPFP \| xHP Stage 3 \| VRSF DP \| ARM 5" FMIC + Hose Upgrades \| GFB DV+ \| VMR 19" v703
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11-09-2017, 01:00 PM	#4
AJL Private 30 Rep 56 Posts Drives: 2011 335i M Sport Join Date: Oct 2015 Location: Bradenton, FL, USA iTrader: (0)	I have similar idle fluctuations. At this point it's been happening for so long that I'm not sure if it started right when the DP was installed, or a little while after that. Coils and plugs were replaced around the same time. Exhaust shop confirmed there was no leak after installing. VRSF Downpipe, FMIC, ER CP, MHD Stage 2+ (93 Oct), Xhp Stage 3, K&N Drop-in. My car has been seeing lots of timing corrections lately, so I'm changing the plugs this weekend, I'll also be cleaning the MAF to see if that helps at all with this specific issue. I was very careful during the original install to make sure that the O2 sensors went back in the correct places (I mean, there's only 2..), so I highly doubt that's the issue. However I suppose it's possible that one of the sensors was damaged during the install, but if I have any luck solving the issue, I'll let ya'll know. For right now, it's really not that big of a deal since the car runs perfectly otherwise.
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11-09-2017, 01:01 PM	#5
Turbod Major 396 Rep 1,210 Posts Drives: 2014 E84 X1 35i M Sport Join Date: Mar 2015 Location: Oregon iTrader: (0)	I had/have two different issues with the 335i. The first one was with the JB4 the wastegate setting needed to be adjusted because it would pulsate under load. I would be climbing a hill and you could hear the pulse through the exhaust. The one I still currently deal with is inconsistent idle when turning the car at low speeds or in reverse. I always just assumed it was due to the load of the power steering pump. __________________ 2011 E92 335i \| 11.7@125 SOLD 2017 Camaro SS \| 12.7@114 SOLD 2019 Audi TT RS \| 10.5@130 SOLD 2020 F97 X3M \| 11.0@123 2023 G80 M3 xDrive
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11-09-2017, 01:46 PM	#6
FireBlaze Private First Class 67 Rep 143 Posts Drives: 2013 E92 335i 6MT M-Sport Join Date: Mar 2016 Location: Torrance, CA iTrader: (0)	I have this issue too. Barely noticeable but its there... Still trying to figure it out but something i can definitely live with it as long is it doesn't hurt the car. __________________ VRSF DP, VRSF 7" Intercooler, BMS OCC, Stg 2 LPFP, Custom MHD E30 Tune, Late Model E-Series N55
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11-09-2017, 03:02 PM	#7
xxMike61 First Lieutenant 78 Rep 239 Posts Drives: 2011 335i Coupe Join Date: Feb 2017 Location: Sacramento, CA iTrader: (0)	Yeah I am also having crazy pulses when in turning in reverse and drive on low throttle. Very weird. Happened before I modded anything __________________ 2011 335i M-Sport E92 MHD E30 \| Phoenix Racing CP \| K&N Drop In Air Filter \|Fuel-it Stage 2 LPFP \| xHP Stage 3 \| VRSF DP \| ARM 5" FMIC + Hose Upgrades \| GFB DV+ \| VMR 19" v703
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11-09-2017, 09:18 AM	#3
weehe126 Brigadier General 1161 Rep 3,189 Posts Drives: 2017 340i Join Date: Apr 2014 Location: San Antonio iTrader: (2)	I've been dealing with this ever wince I installed my vrsf dp as well, 50k miles ago. I've got a new O2 sensor to put in to see if it fixes it. I think it just happens to some cars when going catless.
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11-09-2017, 06:53 PM	#9
rich_mane First Lieutenant 139 Rep 227 Posts Drives: 2011 E92 335i Join Date: Jan 2016 Location: S.FL iTrader: (1)	I'm pretty sure BMW even had a bulletin about the idle fluctuating at low speeds or turning. Was a pretty common problem that they supposedly solved with DME programming... Maybe raised the idle slightly or something
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11-09-2017, 08:00 PM	#10
Mean E92 Private First Class 40 Rep 177 Posts Drives: 2011 BMW E92 335i Join Date: Jun 2016 Location: San Francisco, California iTrader: (0)	Yeah I have the same issue. I noticed it after installing the dp which is catless. So the N55 must be very sensitive to no cat.
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11-09-2017, 11:41 PM	#11
RickySATX New Member 5 Rep 20 Posts Drives: 2011 E90 335i Join Date: Apr 2011 Location: Omaha, Nebraska iTrader: (0)	I've had idle issues for as long as I can remember, even when I was all stock. PPK flashed help some and got rid of the stalling for the most part. Now I'm FBO w/MHD and when coming to a stop RPMs drop to at or below 500 and continue to bounce around at idle. Sometimes fluctuations vary from 500 rpm to 900 rpm. It's stupid annoying but I've come to realize this is just a quick with this car. I think rpm adjustment via MHD would help this issue but I don't see them addressing this anytime soon.
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11-16-2017, 09:25 PM	#13
E46toE90 Sparkling Graphite Metallic FTW 151 Rep 3,212 Posts Drives: lci m-sport e90 n55 Join Date: Jun 2010 Location: the bronx iTrader: (12)	What are the chances of it being due to the pcv valve in valve cover? My n55 also does idle surges. There was a time I did oil change and forgot to tighten oil cap my idle surge was insane I had to pull over and check. My pcv went bad so seals were howling once you pull oil cap noise goes away. So what are the chances of when I do valve cover idle surges go away? Let you guys know Sunday!!!
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11-16-2017, 11:28 PM	#15
Mean E92 Private First Class 40 Rep 177 Posts Drives: 2011 BMW E92 335i Join Date: Jun 2016 Location: San Francisco, California iTrader: (0)	I still have it even after getting a new VC, thinking it was my PCV valve. I honestly think it has to do with catless dps. Or something VANOS related. These cars are so complicated to the point were it's almost impossible to diagnose something.
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11-27-2017, 09:51 PM	#16
Boo$ted_in_ri Private First Class 30 Rep 159 Posts Drives: 2011 335i Join Date: Apr 2017 Location: RI iTrader: (0)	My car does this every morning when I leave for work. I’m just always ready for it now. I get pretty pissed when I’m pulling into a parking spot and it jumps forward quick on me tho! Lol
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11-28-2017, 10:49 AM	#17
OneMoreAlex Second Lieutenant 45 Rep 194 Posts Drives: 2012 e92 335i Join Date: Aug 2015 Location: Long Island, NY iTrader: (0)	Not saying this will solve your problem, but I had the same thing happen. I tried chasing it down for months and finally seemed to find where it's coming from. Finally what seemed to fix my issue was when I switched back to my factory air intake instead of running the BMS intake. Haven't had this problem once since. __________________ 12' 335i \| CP-E CP \| MHD \| VRSF DP \| ALPINA B3 \|
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12-02-2017, 11:29 AM	#20
weehe126 Brigadier General 1161 Rep 3,189 Posts Drives: 2017 340i Join Date: Apr 2014 Location: San Antonio iTrader: (2)	I had the issue with the stock intake and it didn't change when I put the BMS intake on. I've noticed when my oil level is closer to +1qt, it gets worse. If I keep my oil level at max it almost stops completely. So I believe it has to do with the vanos solenoids and oil pressure.
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12-02-2017, 10:32 PM	#21
MiamiM3 Second Lieutenant 32 Rep 205 Posts Drives: 2011 335i E90 AT M-Sport Join Date: May 2011 Location: Sacramento CA iTrader: (1) Garage List 2011 BMW 335i M-Sport [0.00]	I also have the rpm surging from 500 to 900 rpms when the car is in reverse or when making tight turns into parking spots. I have stock intake with K&N drop in filter. I am at a total loss with this issue and it is driving me crazy.
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