Can someone please help me, I might have the strangest N54 issue

Miller335 · 08-18-2016, 12:24 PM

I have what I call a "bump" or a "thump" when going WOT and RPMs climb.
My logs look near PERFECT. The only thing that is even a clue in the logs is the rpms DROP ever so slightly while this "bump" happens.

Look at the log around 4k rpms in this log and you'll see it happening.
Does anything else in the log stand out?

I've changed plugs and the issue persisted.
I ditched stock DVs to a Tial BOV and still the same.
I've tried various MHD tunes, still exists.

Seems to be only under high load/lows rpms, as soon as rpms get over 4k or so it never happens.

At my wits end, car runs perfect otherwise, no misfires or codes.

Can someone please help?

Log: http://www.datazap.me/u/miller335/71...og=0&data=4-22

Msport335 · 08-18-2016, 12:33 PM

most likely a slight loss of traction/bump in the road

Miller335 · 08-18-2016, 02:16 PM

Quote:

Originally Posted by Msport335

most likely a slight loss of traction/bump in the road

All traction aids off and road is 100% smooth.

V8bait · 08-18-2016, 02:19 PM

How long since you had your valves nutted on?

theweebabySeamus · 08-18-2016, 02:20 PM

Quote:

Originally Posted by V8bait

How long since you had your valves nutted on?

+1

Or coils. Probably not but you never know.

Miller335 · 08-18-2016, 02:34 PM

Quote:

Originally Posted by V8bait

How long since you had your valves nutted on?

10k miles ago

Miller335 · 08-18-2016, 02:37 PM

Quote:

Originally Posted by theweebabySeamus

+1

Or coils. Probably not but you never know.

I'm going to clean vanos solenoids when I change my oil in a few weeks also.
Probably wouldn't hurt to change coils but no misfires or nothing.

I hate just throwing parts at the car blindly though.

wren57 · 08-18-2016, 03:14 PM

Solution: downshift.

Cost: $0.

2011z435is · 08-18-2016, 03:15 PM

there is a throttle closure right where you are talking about, probably related to that.

Miller335 · 08-18-2016, 04:05 PM

Quote:

Originally Posted by 2011z435is

there is a throttle closure right where you are talking about, probably related to that.

Good catch!
What do you think would cause this?

mojobmw_e90 · 08-18-2016, 04:14 PM

Quote:

Originally Posted by Miller335

Good catch!
What do you think would cause this?

I remember Terry talking about how the ecu manages fuel by shutting the throttle down to compensate for ignition timing regardless if ur foot was 100% on the pedal

08-18-2016, 04:18 PM

There's definitely something wonky going on in between 4021 and 4215 rpm, not related to throttle closure. AFR between the two banks goes wacky, then recovers.

I've heard of new primary O2 sensors fixing similar issues during low load situations, but not sure if a new set will help you here. Interested in hearing what the more knowledgeable members have to say though

cstmx_ryder · 08-18-2016, 05:18 PM

Have you switched back to stock tune? Try that and see if it still happens.....

Miller335 · 08-18-2016, 06:27 PM

Quote:

Originally Posted by cstmx_ryder

Have you switched back to stock tune? Try that and see if it still happens.....

I've ran an agrressive pump gas tune and it doesn't happen.

Only when I run an E85 does it seem to happen.

Chromey · 08-18-2016, 07:38 PM

I had a hiccup and it was a leaking injector.. Ran lean then dumped rich , felt like a mis ...

Miller335 · 08-18-2016, 09:48 PM

Quote:

Originally Posted by Chromey

I had a hiccup and it was a leaking injector.. Ran lean then dumped rich , felt like a mis ...

That's exactly how describe, like a miss./hiccup.

Julian2485 · 08-18-2016, 10:20 PM

Quote:

Originally Posted by Miller335

I have what I call a "bump" or a "thump" when going WOT and RPMs climb.
My logs look near PERFECT. The only thing that is even a clue in the logs is the rpms DROP ever so slightly while this "bump" happens.

Look at the log around 4k rpms in this log and you'll see it happening.
Does anything else in the log stand out?

I've changed plugs and the issue persisted.
I ditched stock DVs to a Tial BOV and still the same.
I've tried various MHD tunes, still exists.

Seems to be only under high load/lows rpms, as soon as rpms get over 4k or so it never happens.

At my wits end, car runs perfect otherwise, no misfires or codes.

Can someone please help?

Log: http://www.datazap.me/u/miller335/71...og=0&data=4-22

Are you xi and manual or auto ?

Miller335 · 08-19-2016, 10:01 AM

Quote:

Originally Posted by Julian2485

Are you xi and manual or auto ?

RWD 6MT

Miller335 · 08-19-2016, 11:10 AM

Quote:

Originally Posted by Chromey

I had a hiccup and it was a leaking injector.. Ran lean then dumped rich , felt like a mis ...

Did u have other symptoms?
Or just this WOT issue Im also having?

Miller335 · 08-25-2016, 03:31 PM

Any other causes for this other than injectors?

Doesn't seem to have this issue on pump gas.

I don't want to spend over $1k on injectors for it to be a maybe fix.

335is-dct · 08-25-2016, 04:36 PM

weird. i definitely see the rpm bump and corresponding fluctuations in boost. could be coils or maybe switch out to a different plug.

i do however see that your lpfp is taking a big hit immediately prior, dipping down to about 50psi, but i'm not sure if its related. you mention this "bump" only happens on e85, so it may have something to do with the increased fueling demand. might be time to invest in a new pump.

Miller335 · 08-25-2016, 05:48 PM

Quote:

Originally Posted by 335is-dct

weird. i definitely see the rpm bump and corresponding fluctuations in boost. could be coils or maybe switch out to a different plug.

i do however see that your lpfp is taking a big hit immediately prior, dipping down to about 50psi, but i'm not sure if its related. you mention this "bump" only happens on e85, so it may have something to do with the increased fueling demand. might be time to invest in a new pump.

I have a stock pump and a walbro 255 inline, what should I jump up to you think?

08-18-2016, 12:24 PM	#1
Miller335 Colonel 293 Rep 2,189 Posts Drives: 2007 E92 Join Date: Oct 2013 Location: Portland, OR iTrader: (0)	Can someone please help me, I might have the strangest N54 issue I have what I call a "bump" or a "thump" when going WOT and RPMs climb. My logs look near PERFECT. The only thing that is even a clue in the logs is the rpms DROP ever so slightly while this "bump" happens. Look at the log around 4k rpms in this log and you'll see it happening. Does anything else in the log stand out? I've changed plugs and the issue persisted. I ditched stock DVs to a Tial BOV and still the same. I've tried various MHD tunes, still exists. Seems to be only under high load/lows rpms, as soon as rpms get over 4k or so it never happens. At my wits end, car runs perfect otherwise, no misfires or codes. Can someone please help? Log: http://www.datazap.me/u/miller335/71...og=0&data=4-22 __________________ 2007 E92 335 6MT w/335is clutch FBO MHD E60 Wedge map 49k miles
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08-18-2016, 12:33 PM	#2
Msport335 Captain 99 Rep 804 Posts Drives: 2009 335i m-sport e90 Join Date: May 2013 Location: Burlington iTrader: (0)	most likely a slight loss of traction/bump in the road __________________ E90 LCI M-sport/ 6AT/ LSD/ FBO+
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08-18-2016, 02:19 PM	#4
V8bait Lieutenant 406 Rep 574 Posts Drives: e92 335i 6mt Join Date: Oct 2011 Location: Houston iTrader: (1)	How long since you had your valves nutted on?
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08-18-2016, 03:14 PM	#8
wren57 Roll Tide 605 Rep 2,363 Posts Drives: 335i Join Date: Jul 2010 Location: St Louis iTrader: (10)	Solution: downshift. Cost: $0. __________________ Fix your broken/stripped cowl bolts with this elegant brass solution! http://www.e90post.com/forums/showthread.php?p=20230306
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08-18-2016, 03:15 PM	#9
2011z435is Private First Class 58 Rep 96 Posts Drives: 2011 z4 sdrive35is Join Date: Feb 2016 Location: cleveland iTrader: (0)	there is a throttle closure right where you are talking about, probably related to that.
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08-18-2016, 04:18 PM	#12
FCobra94 Guest 0 Rep n/a Posts Drives:	There's definitely something wonky going on in between 4021 and 4215 rpm, not related to throttle closure. AFR between the two banks goes wacky, then recovers. I've heard of new primary O2 sensors fixing similar issues during low load situations, but not sure if a new set will help you here. Interested in hearing what the more knowledgeable members have to say though
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08-18-2016, 05:18 PM	#13
cstmx_ryder Colonel 171 Rep 2,875 Posts Drives: A metal box with a roundel Join Date: Jul 2007 Location: Portland, OR iTrader: (2)	Have you switched back to stock tune? Try that and see if it still happens..... __________________ '08 AW E90 335i PROcede V5 \| BMS DCI \| RR DPs \| ETS FMIC \| FORGE DVs \| Stett CP \| Vanguard \| PSS10
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08-18-2016, 07:38 PM	#15
Chromey Captain 100 Rep 615 Posts Drives: 09 E93 M3 Join Date: Jan 2014 Location: Victoria bc iTrader: (0)	I had a hiccup and it was a leaking injector.. Ran lean then dumped rich , felt like a mis ...
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08-25-2016, 03:31 PM	#20
Miller335 Colonel 293 Rep 2,189 Posts Drives: 2007 E92 Join Date: Oct 2013 Location: Portland, OR iTrader: (0)	Any other causes for this other than injectors? Doesn't seem to have this issue on pump gas. I don't want to spend over $1k on injectors for it to be a maybe fix. __________________ 2007 E92 335 6MT w/335is clutch FBO MHD E60 Wedge map 49k miles
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08-25-2016, 04:36 PM	#21
335is-dct Second Lieutenant 190 Rep 232 Posts Drives: 335is Join Date: Dec 2015 Location: south florida iTrader: (0)	weird. i definitely see the rpm bump and corresponding fluctuations in boost. could be coils or maybe switch out to a different plug. i do however see that your lpfp is taking a big hit immediately prior, dipping down to about 50psi, but i'm not sure if its related. you mention this "bump" only happens on e85, so it may have something to do with the increased fueling demand. might be time to invest in a new pump.
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