E90Post
 


MINHS Automotive
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > rpm unstable when warm start up



Reply
 
Thread Tools Search this Thread
      04-16-2015, 05:01 PM   #1
trickystar
Enlisted Member
0
Rep
31
Posts

Drives: 07 335i coupe manual
Join Date: Jan 2015
Location: Vancouver

iTrader: (0)

Question rpm unstable when warm start up

my rpm would go up and down inbetween 500 to 900 rpm for like 20 seconds when i start up my car when its warm and then go back to stable 750 rpm

also when i have to come to a complete stop when i am on 2nd gear (the car was already reduced to a very slow speed, rpm may be at around 2k?), i engage the clutch fully and put the stick to neutral, right when i engage the clutch the rpm will drop to lower then 500, close to 400rpm, i could feel the engine shake and almost stall and it will bounce back up to 750rpm

i believe this is still some what early stage of a problem cuz i can see later on when it get worse, instead of the rpm dropping to 500ish, it will just drop all the way to 0 and the car will stall. anyone out here have any suggestion of what is the cost?

information about my car
2007 e92 n54
just bought it 2 months ago
43496 miles
spark plug changed 500 miles ago (first time ever, ex owner never changed them)
walnut blast done 1000 miles ago


with these done i should be looking at coil packs next right?
what i am thinking is the old spark plug was damaging the coil packs because they were tooooooooooo old and worn out and need way more electricity produced from coil to get the spark, that will put the coil to over heat and turn bad? not sure if my theory is right tho.. i am still pretty new at this so please help me out!!

and just in case i do have to change my coil packs
should i be looking at the oem ones or aftermarket ones like this?

http://www.vivaperformance.com/ip-co...xi-n54-engine/


Appreciate 0
      04-17-2015, 12:29 AM   #2
N54Fiend
Professional idiot
1
Rep
82
Posts

Drives: 2012 335is
Join Date: Jun 2012
Location: Central FL

iTrader: (1)

Does the car turn over right away on a cold start, or crank for a while? Also, have you gotten any reduced power codes by chance?
Appreciate 0
      04-17-2015, 09:58 AM   #3
trickystar
Enlisted Member
0
Rep
31
Posts

Drives: 07 335i coupe manual
Join Date: Jan 2015
Location: Vancouver

iTrader: (0)

on cold start the rpm would stay at around 1k steady and then go back down to 650~700 in a very steady speed, never jumped up and down like on warm start

and no code came up yet so far =[

any idea?
Appreciate 0
      04-17-2015, 11:45 AM   #4
hoopvillian
Private First Class
hoopvillian's Avatar
5
Rep
141
Posts

Drives: 335i
Join Date: Apr 2010
Location: Dago

iTrader: (0)

Check vacuum hoses, might be a boost leak. Just a guess.
Appreciate 0
      04-17-2015, 04:59 PM   #5
fr3nch2
Private
0
Rep
73
Posts

Drives: 2008 BMW 335i
Join Date: Feb 2013
Location: United States

iTrader: (0)

Do you have a way to check for codes?
__________________
BMS DCI, OpenFlash Stage 1, Lux E90 v5.2, ECS 15mm Spacers, ECS Cross-Drilled & Slotted Rotors, ZiZa Smoked LED Sidemarkers
Appreciate 0
      04-18-2015, 09:38 PM   #6
trickystar
Enlisted Member
0
Rep
31
Posts

Drives: 07 335i coupe manual
Join Date: Jan 2015
Location: Vancouver

iTrader: (0)

i use cobb v3 to check for codes, but no code shown. about the vaccum hose, how do i check if its leaking?
Appreciate 0
      Today, 01:26 AM   #7
N54Fiend
Professional idiot
1
Rep
82
Posts

Drives: 2012 335is
Join Date: Jun 2012
Location: Central FL

iTrader: (1)

Are you using the cobb to tune the car? If you are, when you de-tune the car, are the issues as noticeable? Same problems?
Appreciate 0
      Today, 01:28 AM   #8
Zach335i
Private
United_States
0
Rep
60
Posts

Drives: 335i
Join Date: Oct 2014
Location: Myrtle Beach, South Carolina

iTrader: (0)

You might have some bad fuel injectors. Early 2007s builds weren't included in the recall.
Appreciate 0
Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 11:07 AM.




e90post
e90post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST