Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

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 07-29-2009, 09:48 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Intermittant mysterious misfire

I am looking for a diagnosis for a mysterious very intermittant misfire before I go to the dealer. Car is a 2004 325iA with 63K miles. Always ran great until now. A few weeks ago at a stop light my idle suddenly dropped a little, car shook a little, then recovered and was fine. It happened a few more times about 2 minutes apart. No check engine light came on. Later I checked the OBD with my reader and no stored codes were present. Later the same thing happened a few time, but with no regularity. I thought possible bad gas or water in the tank so I added fuel additive to the next 2 tanks and the problem went away. Last week it returned more pronounced but it did trip the check engine light. My reader said it was P0303, misfire on cylinder 3. After doing a lot of reading on different forums I opted to swap the coil on cylinder 3 with number 1. Also changed to a new plug on number 3. Problem did not go away but remained very intermiitant. Reader said was still on cylinder 3. Some days it was gone completely, other days it was there during one driving session, but when I turned car off and re-started it later, it was gone. Today I disconnected the battery cable for 30 minutes to see if it would reset the computer. Still problem remains but is very intermittant. There is no pattern to it. I don't know if this is related or not, but sometimes when I start it up, it starts right away like normal, but othertimes it seems to start weakly initially but then is fine 5 seconds later (not the battery because I checked it and it is fine).
When it runs it runs great, when this problem happens it idles poorly but generally runs fine when not idling. It is always a code P0303. Does the dealer have a scan tool that is more sophistcated than my OBD-2 reader which might show more information. Dealer recommeds I keep driving it some more so more information gets stored in the computer which might help diagnose problem. I am simply trying to exhaust everything I can do befor taking it into dealer.
Reply With Quote
Ads by Google
  #2  
Old 07-29-2009, 02:57 PM
jh jh is offline
Officially Welcomed to the 'Fest
Location: MD
 
Join Date: Jul 2003
Posts: 125
Mein Auto: 13 335is, 74 2002, 04 330
Yes, dealers and independents with BMW diagnostic computers get a lot more code information... but some detective work may still be required.
Reply With Quote
  #3  
Old 07-29-2009, 04:14 PM
smolck's Avatar
smolck smolck is offline
ROLL TIDE!
Location: Birmingham, AL
 
Join Date: Jul 2007
Posts: 22,335
Mein Auto: 2004 ZHP Sedan
I'd pull the spark plug on ol' #3 and see how she looks. Could just be a bad plug. Better yet, replace them all, cheaper than a bogus dealer scan.
__________________

Check out my YouTube Channel for DIY's and other fun stuff HERE
Check out my BMWBLOG!
Quote:
Originally Posted by Fast Bob View Post
now, go burn your Man Card, and buy yourself a Camry....
Reply With Quote
  #4  
Old 07-29-2009, 05:17 PM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
I put a new plug in number 3 when I swapped the coils, so the current plug should be fine. The old plug looked OK when I removed it. My thoughts are injector problem or some type of computer related problem, bit I am really at a loss. It only happems maybe 10% of the time. The rest of the time it runs great. I have read all the old posts on intermittant single cylinder misfires and can not find any common answers after changing the plug and swapping coils, which did not cure the problem. And when it is not misfiring, it runs great, cannot even tell the engine is runnning at an idle sometimes.
Reply With Quote
  #5  
Old 07-29-2009, 05:27 PM
raymondaecom raymondaecom is offline
Registered User
Location: NJ
 
Join Date: May 2009
Posts: 10
Mein Auto: 2001 BMW 325i
do u have camshaft sensor code?
did ur car die at idle??
Reply With Quote
  #6  
Old 07-29-2009, 05:52 PM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
It has never died. Only code ever was P0303, misfire on cylinder 3.
Reply With Quote
  #7  
Old 07-30-2009, 05:50 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Update on problem this morning. I started car fine, drove off. After about a mile the check engine light came on. I checked code right away and it showed misfires on 1,2,and 3 and a random misfire. It idled poorly at stop lights. I pulled over, turned it off. Waited a few minutes, started it again and it ran fine. So does this help or confuse it more?
Reply With Quote
  #8  
Old 07-30-2009, 07:02 AM
CaptainTrap's Avatar
CaptainTrap CaptainTrap is offline
a man made of men like me
Location: Bethel, CT
 
Join Date: Jun 2007
Posts: 836
Mein Auto: 2001 330i 5MT ZSP
camshaft position sensor?

torn intake boot?

these the the common things that people always suggest with misfires. I am currently fighting intermittent misfires too. no solution yet. after replacing the fuel injector seals the misfires started occurring less frequent if that helps.
__________________
2001 330i ZSP 5MT H&R Sport Cup Kit 18" VMR v710 18x8.5

BMW CCA #: 399644
Reply With Quote
  #9  
Old 07-30-2009, 09:50 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Could the CCV valve be going out on my car? Could that cause the misfires?
Reply With Quote
  #10  
Old 07-30-2009, 01:48 PM
CaptainTrap's Avatar
CaptainTrap CaptainTrap is offline
a man made of men like me
Location: Bethel, CT
 
Join Date: Jun 2007
Posts: 836
Mein Auto: 2001 330i 5MT ZSP
some may say so, i replaced mine because of some recommendations and it didnt solve my problem. depending on your mileage you may want to do it as preventative maintenance anyway. if you are DIYing that is. a dealer service would cost hundreds of doallars. DIY is like $250 in parts and a few hours of your time.
__________________
2001 330i ZSP 5MT H&R Sport Cup Kit 18" VMR v710 18x8.5

BMW CCA #: 399644
Reply With Quote
  #11  
Old 07-30-2009, 06:11 PM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Drove home today after my 4 code morning drive into work, car ran great, The 4 codes from this morning were all gone when I connected the scanner at home. So these are pending codes that go away after awhile. So my misfires and the codes are very intermittent. When it isn't misfiring, it runs great, no notice of any problem. There has to be an explanation for this. I am going to try to see if there is a pattern of it happening only on the first start up in the morning.
Reply With Quote
  #12  
Old 07-30-2009, 06:58 PM
CaptainTrap's Avatar
CaptainTrap CaptainTrap is offline
a man made of men like me
Location: Bethel, CT
 
Join Date: Jun 2007
Posts: 836
Mein Auto: 2001 330i 5MT ZSP
MAF airflow sensor?

cracked intake boot?

these could cause cold start misfires.

have you inspected the intake boot for cracks yet? make sure you inspect the smaller tube coming off the main lower boot before it goes into the intake manifold butterfly valve. the smaller tube goes into the Idle Control Valve.

try using the search function of this forum and search these terms i have been throwing at you to read and familiarize your self with what others have experienced. search threads started by myself to see the steps i have taken to eliminate over 8 codes. i whittled my way down to 2 codes and now i am stuck.
__________________
2001 330i ZSP 5MT H&R Sport Cup Kit 18" VMR v710 18x8.5

BMW CCA #: 399644
Reply With Quote
  #13  
Old 07-31-2009, 06:03 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
I did clean the MAF sensor as one of my first steps when the problem started. It helped for a few days but problem returned. I am going to check vacuum hoses as you suggested. This morning on a cold start it started perfect, ran perfect to work, no codes just a great ride in. On Monday I am taking it to indy shop for replacement of control arm bushings and they will look at it for the misfire as well. They can do a smoke test as well to check for unseen leaks. I may still have to take it to the dealer because I think the dealer has a more sophisticated scan reader that "interrogates" the BMW computer more than simply reading the OBD codes. If someone out there knows if this is true I would appreciate an answer on it. I have read lots of posts and forums on this issue, and seen that many have had this intermittant misfire problem but I have yet to see any post where someone says they definitley found the solution and cured the problem.
Reply With Quote
  #14  
Old 07-31-2009, 08:09 AM
CaptainTrap's Avatar
CaptainTrap CaptainTrap is offline
a man made of men like me
Location: Bethel, CT
 
Join Date: Jun 2007
Posts: 836
Mein Auto: 2001 330i 5MT ZSP
if cleaning the MAF made the problem go away it may be a failing MAF sensor although there is a MAF error code that would be thrown. I replaced my MAF in hopes it would cure my ailments but no such luck. i would advise against this as it is an expensive part. rather find someone with the same car and known working MAF and swap to see for yourself. if so order a new one. I believe BMW shops use the GT1 computer scanner to read the modules of the car. It is true that this device offers greater insight than any end user OBD II scanner can offer. Good luck
__________________
2001 330i ZSP 5MT H&R Sport Cup Kit 18" VMR v710 18x8.5

BMW CCA #: 399644
Reply With Quote
  #15  
Old 07-31-2009, 05:14 PM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Funny you should say to try swapping the MAF sensor with someone who has the same car to see if it is the problem. I actually have another 325 five feet away in my same garage. Of course, it is my wifes convertible....and she is out of town.....hmmmmm. Actually I had thought of that but I don't think it is a bad MAF. Today the car ran great all day. No misfire and idle was very smooth. I added more fuel additive, the Techron type, and car felt like it was on steroids. Ran better than I remember in a long time. I am starting to wonder if I had a clogged injector and I have to keep adding additive to burn it clean.
Reply With Quote
  #16  
Old 07-31-2009, 05:19 PM
smolck's Avatar
smolck smolck is offline
ROLL TIDE!
Location: Birmingham, AL
 
Join Date: Jul 2007
Posts: 22,335
Mein Auto: 2004 ZHP Sedan
captain trap, your problem is far different than this one.

OP, I still think you need to pull ALL your plugs and check them. You said they were "fine" but I don't know what that means. If you are misfiring the plugs will tell you if you are lean or rich. That will help you determine the problem.
__________________

Check out my YouTube Channel for DIY's and other fun stuff HERE
Check out my BMWBLOG!
Quote:
Originally Posted by Fast Bob View Post
now, go burn your Man Card, and buy yourself a Camry....
Reply With Quote
  #17  
Old 08-01-2009, 12:20 AM
jw08 jw08 is offline
Officially Welcomed to the 'Fest
Location: Santa Clara, CA
 
Join Date: Dec 2008
Posts: 308
Mein Auto: 2003 330i ZHP
Does your car have BREMI or Bosch ignition coils?

If you have access to a generic OBD2 scan tool (not just a code reader) -- what are the short and long term fuel trim readings at a warm idle?

If you don't have access to a more functional scanner, I would continue with having your shop smoke test the intake and take a fuel pressure reading as well.
Reply With Quote
  #18  
Old 08-01-2009, 05:28 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
I have the Bosch coils. I was thinking about pulling and replacing the other 5 plugs more out of concern that they had 63K miles on them and they were an easy DIY than that they were the cause of the misfires. The one I replaced from No.3 was light brown in color, and not wet or black or white. The tip did not appear to be worn much. It actually looked OK. And remember that after I replaced that plug, the same problem occurred in the same cylinder. That is why I didn't think the plug was the problem.

I don't personally have a scanner other than my OBD 2 code reader, but I will still have the indy shop on Monday connect theirs up to it to see what they get. Does any one here think it could be fuel related, and continued adding additives might cure it?
Reply With Quote
  #19  
Old 08-01-2009, 08:14 AM
jw08 jw08 is offline
Officially Welcomed to the 'Fest
Location: Santa Clara, CA
 
Join Date: Dec 2008
Posts: 308
Mein Auto: 2003 330i ZHP
Quote:
Originally Posted by djs1122 View Post
I have the Bosch coils. I was thinking about pulling and replacing the other 5 plugs more out of concern that they had 63K miles on them and they were an easy DIY than that they were the cause of the misfires. The one I replaced from No.3 was light brown in color, and not wet or black or white. The tip did not appear to be worn much. It actually looked OK. And remember that after I replaced that plug, the same problem occurred in the same cylinder. That is why I didn't think the plug was the problem.

I don't personally have a scanner other than my OBD 2 code reader, but I will still have the indy shop on Monday connect theirs up to it to see what they get. Does any one here think it could be fuel related, and continued adding additives might cure it?
A single cylinder misfire can only be caused by so many things and you've eliminated most of them. If we figure the coil and plug are known goods, the only other things I can think of are a vacuum leak that is affecting only that cylinder, an engine mechanical problem (not likely as it is intermittent) or a bad injector. An injector can (and the ones I've seen fail more often than not have) fail intermittently... I had a Toyota a few weeks ago that would misfire on #2 only after it was hot, hot hot and it turned out to be the injector. You'd have to try swapping them or just installing a new one. I haven't removed the injectors from an E46, so I'm not sure how hard it is. I wouldn't keep spending money on things like Techron though as it's more likely that the injector solenoid is failing than it being plugged up.
Reply With Quote
  #20  
Old 08-01-2009, 10:16 PM
pepsicola47 pepsicola47 is offline
Registered User
Location: Melbourne
 
Join Date: Jul 2009
Posts: 19
Mein Auto: 330i
I would say the next thing you can try to do is swapping your injectors. Say with cylinder 3 and cylinder 4.
There might be a slight leakage in the injector that's causing the problem. I worked in BMW, and it's not rare to see E46 having a failed injector. Although most of them would have run rough first time you started after you left it overnight. So it's a little bit different do you situation.
And the 6 cylinder engine DME is prone to fail too.
Reply With Quote
  #21  
Old 08-02-2009, 12:29 AM
CaptainTrap's Avatar
CaptainTrap CaptainTrap is offline
a man made of men like me
Location: Bethel, CT
 
Join Date: Jun 2007
Posts: 836
Mein Auto: 2001 330i 5MT ZSP
here is a DIY with pics i made a few months ago when i was chasing codes and found a leak around my injectors. it will tell you how to diagnose, remove and replace the injectors and/or seals. keep us posted about your shop visit on monday. hopefully they wont keep it for a week like my shop did and never call you...your shop probably doesnt have a smoking hot blond english women answering the phones though...

LINK: http://www.bimmerfest.com/forums/sho...709&highlight=
__________________
2001 330i ZSP 5MT H&R Sport Cup Kit 18" VMR v710 18x8.5

BMW CCA #: 399644
Reply With Quote
  #22  
Old 08-03-2009, 08:29 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
My string of 4 days without a misfire ended today as I was driving the car to the indy shop. It was cylinder 3 again so they were to look at it. They just called me. The guy said in his 30 years of BMW experience, it is rarely the injector. Most often it is plug, then coil, then intake vacuum leak, then ground problems, then possible head gasket. We discussed the fact that the battery is the original 5 year old battery and possibly it might be giving off some type of irregular voltage. The Bently manual says irregular voltage can cause a myriad of problems. He suggested I first change the battery since I got decent life out of it, then check all the grounds, including the coil ground for number 3. So once I get the car back from them replacing the control arm bushings, I think I will replace the battery, then see what happens next for the car. I am trying to do one thing at a time, then wait to see if the misfire re-occurs before trying the next thing, so as to isolate the problem. So its battery first, then check and clean all ground connections next.
Reply With Quote
  #23  
Old 08-11-2009, 09:01 AM
djs1122 djs1122 is offline
Officially Welcomed to the 'Fest
Location: Houston Texas
 
Join Date: Jul 2009
Posts: 140
Mein Auto: 2004 325iA
Update one week after having car at the indy who didn't do anything for the misfire but did replace the CAB. I replaced the battery with Autozone 49DL, all terminals were perfectly clean and tight. Car ran fine without misfires for 4 days, then started the misfire on cylinder 3 again. I decided to replace the remaining plugs which were original with 63K miles. All remaining plugs (Bosch) looked very good, but the one I pulled out earlier from cylinder 3 was a darker brown than the rest which were a light brown/gray color. Car ran great on new plugs for a day but misfires on cylinder 3 happened again the next day. After restarting the car it went away. I again swapped the coil on number 3 with number 2 just to see again if it did anything. No misfires yet. Finally decided I was tired of this so I dropped it off at the dealer today. They said it may take a few days to diagnose since it is so intermittant. Service guy said usually intermittant misfires are coils but could also be the DME which is covered by an 8 year, 80K warranty. I did not know that. So I am waiting for a call and will post what I learn.
Reply With Quote
  #24  
Old 08-11-2009, 06:08 PM
2004BMW325Ci 2004BMW325Ci is offline
Officially Welcomed to the 'Fest
Location: Florida
 
Join Date: Aug 2009
Posts: 167
Mein Auto: 2004 325Ci ZSP & ZPP
I too am suffering from the maddening intermittant mysterious misfire. As I posted in another thread, my dealer is telling they think it's the disa valve. However, some people have told me it's next to impossible that the problem is the disa valve so when I take the car back on Thursday I'm going to have them check some of the things that I've learned of here.

I will report back then what they say. I hope they don't have to keep the car. I've only had it for a week and I want to drive the sucker!
Reply With Quote
  #25  
Old 08-12-2009, 09:00 AM
CarlsonTheFlyer's Avatar
CarlsonTheFlyer CarlsonTheFlyer is offline
Paraglide! Walk on air!
Location: Atlanta, GA USA
 
Join Date: May 2009
Posts: 1,255
Mein Auto: 2010 335i Coupe 6MT
A few years ago I had a perpetual P0303 code on my old Rodeo. After weeks of diagnosing, and swapping plugs, coils, etc., couldn't figure it out. Finally I took it to a shop with a smoke machine and found a pinhole leak in the intake manifold gasket at cylinder #3. Replaced it, and problem went away.
__________________
Carlson The Flyer | BMW CCA # 423862
The problem with common sense is that it's not very common.

2010 335i, ZSP, ZPP, M-Sport, Le Mans Blue, 3 pedals of course!
Heated Seats | USB & iPod | Black Dakota Leather
Cobb AP Stage 1 Aggressive + | Cobb FMIC | BMW Performance Exhaust



Previous BMWs:
2001 330i ZSP ZPP 5-speed - sold, but not forgotten.
Reply With Quote
Reply

Bookmarks


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 01:08 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
© 2001-2011 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms