Misfire in 5th gear - Bimmerfest - BMW Forums



Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E46 (1999 - 2006)

E46 (1999 - 2006)
The fourth generation 3 Series (E46 chassis) was introduced in 1999 and set the standard for engineering and performance during it's years of production including being named to Car & Driver's 10 best list every one of those years! ! -- View the E46 Wiki

Reply
 
Thread Tools Display Modes
  #1  
Old 01-02-2018, 10:50 AM
KrankE46 KrankE46 is offline
Registered User
Location: Missouri
 
Join Date: Apr 2017
Posts: 7
Mein Auto: E46 325XI
Misfire in 5th gear

Got a little issue I need help figuring out.

2004 325XI - 250,000 miles

I have a misfire which causes rough running and lose of HP which pops the CEL telling me "Misfire in cylinder #2". This usually happens when I'm cruising @ 3,500 in 5th gear. I can drive all over town without issues, but when I get on the hwy, within a mile or two I have the issue. I do not have the issue in 4th gear at the same rpm's.

I replaced the spark plug and ignition coil, no change.

Question - does the CPU have a different map it goes into when in 5th gear? If so can this be the issue?

Question - how likely is it to be the CPU or a broken wire?
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 01-02-2018, 11:43 AM
acoste's Avatar
acoste acoste is offline
Officially Welcomed to the 'Fest
Location: California
 
Join Date: Nov 2011
Posts: 5,395
Mein Auto: 2010 550i MT
The car at 3500 rpm 5th gear constant speed needs more horsepower than at 3500 rpm 4th gear. This is due to the air flow resistance.
If there are performance differences between cylinders, they are more likely to show at high power output.

Swap injectors between cylinders, see if the misfire moves. And check compression.
__________________
__________________
2010 BMW 550i MT
2003 BMW 325i @216k and counting
1998 BMW 528i MT @ 231k //sold
1997 Saab 9000 //sold
Reply With Quote
  #3  
Old 01-03-2018, 06:43 AM
marcozandrini marcozandrini is offline
Officially Welcomed to the 'Fest
Location: Virginia
 
Join Date: Feb 2014
Posts: 5,259
Mein Auto: 2018 M240i
Misfire in 5th gear

Itís not a broken wire. That would cause a constant problem. How old is the fuel pump? When was the fuel filter last changed? A soft failing fuel pump can cause some odd issues.
Reply With Quote
Sponsored Links
Advertisement
 
  #4  
Old 01-03-2018, 08:29 AM
KrankE46 KrankE46 is offline
Registered User
Location: Missouri
 
Join Date: Apr 2017
Posts: 7
Mein Auto: E46 325XI
Fuel pump and filter replaced in the last 6 months.

Sent from my SM-G920T using Bimmerfest mobile app
Reply With Quote
  #5  
Old 01-04-2018, 06:00 AM
marcozandrini marcozandrini is offline
Officially Welcomed to the 'Fest
Location: Virginia
 
Join Date: Feb 2014
Posts: 5,259
Mein Auto: 2018 M240i
What brand of pump and filter? It does matter.
Reply With Quote
Reply

See More Related BMW Stories

Tags
misfire, misfire in 5th gear


Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > 3 Series & 4 Series > E46 (1999 - 2006)
Today's Posts Search
Thread Tools
Display Modes

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 On



Forum Jump


All times are GMT -7. The time now is 05:31 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
© 2001- VerticalScope Inc. All rights reserved.