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7 Series - E38 (1995 - 2001)

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  #1  
Old 12-10-2010, 09:39 PM
preed preed is offline
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Location: marianna
 
Join Date: Dec 2010
Posts: 3
Mein Auto: 98 740i bmw
Unhappy Rough idle/check engine light flashing

Hello, i need some help figuring out why my 98 740i is idiling rough. It gives me a code for a mis fire on cylinder #1. It also seems to spit and sputter at times when i press the gas pedal. Not sure what's going on but my bimmer sounds like a small truck now. HELP!!!!!
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  #2  
Old 12-10-2010, 09:47 PM
cntlaper1 cntlaper1 is offline
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Location: hartford, CT
 
Join Date: Nov 2010
Posts: 6
Mein Auto: 135I
i guess it could be many things from the ignition coil being faulty, fouled spark plug, bad injector or in some cases engine mechanical damage like a broken valve spring for that cylinder. i would swap coils around and see if the coil that comes off cylinder 1 travels to the cylinder that you installed it into. mark them so you dont forget. those coils fail frequently. cylinder 1 is the closest to the coolant reservour tank.
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  #3  
Old 12-10-2010, 10:57 PM
preed preed is offline
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Location: marianna
 
Join Date: Dec 2010
Posts: 3
Mein Auto: 98 740i bmw
Mis Fire on Cylinder 1/Rough Idle

Hello, i need some help figuring out why my 98 740i is idiling rough. It gives me a code for a mis fire on cylinder #1. It also seems to spit and sputter at times when i press the gas pedal. Not sure what's going on but my bimmer sounds like a small truck now. HELP!!!!!
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  #4  
Old 12-11-2010, 07:43 AM
GLHExorcist GLHExorcist is offline
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Location: Gatineau Quebec Canada
 
Join Date: Dec 2010
Posts: 16
Mein Auto: 1995 740i
Valve cover gaskets are prone to leak as they get hard and brittle from underhood heat. First step is to, like cntlaper1 said, pull the plugs. Usually, if the VC gaskets are leaking, if you shine a light down the plug hole before taking the plug out, you will see oil. You will also see oil on the tip of the coilpack (where it meets with the plug) if the leak is bad enough. This will cause a misfire and foul the plugs in question.

Hope this helps!

Last edited by GLHExorcist; 12-11-2010 at 07:44 AM.
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  #5  
Old 11-04-2015, 03:42 PM
Artheathen Artheathen is offline
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Location: Houston
 
Join Date: Nov 2015
Posts: 3
Mein Auto: 2001 7401
Check ignition coils

Just received word that two ignition coils on my 2001 740i are bad and need replacement. Issue was car would rough idle in park as well as at stop lights....so much so that I was bouncing in my seat. Otherwise it was driving great when not idling. It appears the fault codes indicate coils 2 and 3 need replacement.
Hope this helps.
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  #6  
Old 11-04-2015, 05:06 PM
u.nanimous u.nanimous is offline
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Location: SE Michigan
 
Join Date: Oct 2014
Posts: 2,174
Mein Auto: 1999 740iS, 2001 330xi
OP's last post (of 3 total) was nearly 5 years ago. By now this has either been fixed or the car was sold.

Welcome to the 'fest!
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Before...

After...(this may take a few years, it's my DD and I have bigger projects)

2005 Venture Extended LT - what else you gonna drive when you have 6 kids, cargo and still want better than 10MPG
2000 Impala LS - because you need something to beat the snot out of in a Michigan winter
1999 BMW 740i - why do I have Chevys again?
2001 BMW 330xi - father/son project time!
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  #7  
Old 11-04-2015, 05:48 PM
Artheathen Artheathen is offline
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Location: Houston
 
Join Date: Nov 2015
Posts: 3
Mein Auto: 2001 7401
Thank you!

Thank you for the welcome message.
I have a 2001 740i as original owner. I am trying to keep it until 2021 and for last 3 years have been having issues. Have used this forum for advice and now just getting to contribute. Car has always been dealership repaired so I figured I could repay advice by posting my issues with dealership solutions so others wouldn't have to pay the $$$$$$$ I am paying!
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  #8  
Old 11-04-2015, 07:43 PM
u.nanimous u.nanimous is offline
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Location: SE Michigan
 
Join Date: Oct 2014
Posts: 2,174
Mein Auto: 1999 740iS, 2001 330xi
Orignial owner...OUCH! That depreciation has to hurt. About a month ago I was looking on craigslist and it appears as though the average price for a 740i/iL in my area is down to about $2000 (probably why there has been a recent boost in new owners here). Maybe by 2021 it will go back up due to rarity and in range to become a classic/antique. I got mine last year for $2600 (at least 4th owner).

So please feel free to post all your knowledge, there are about 15 of us active in here that could learn a few things from someone who's driven the car that long. But if the thread is more than a couple years old and the OP has a post count under 20 it might be worth it just to start a new thread.

And then there are threads like what's you odometer reading and what's your look like that can be resurrected anytime. (Hint: show us some pics)
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  #9  
Old 12-15-2015, 03:31 PM
yitbos92 yitbos92 is offline
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Location: Roseville, MI
 
Join Date: Nov 2014
Posts: 78
Mein Auto: 1998 740iL
Quote:
Originally Posted by u.nanimous View Post
OP's last post (of 3 total) was nearly 5 years ago. By now this has either been fixed or the car was sold.

Welcome to the 'fest!
Thankfully this post hasn't disappeared. My car has been starting to do that as of the last couple of weeks. Idles rough as a cob when at a stop light and holding the break, and has some major hesitation when pushing the throttle from a dead stop. I have a new set of plugs for it, might try swapping those out this weekend and see if there's any oil in the plug holes like GLHExorcist mentioned.
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  #10  
Old 12-15-2015, 03:54 PM
Artheathen Artheathen is offline
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Location: Houston
 
Join Date: Nov 2015
Posts: 3
Mein Auto: 2001 7401
Check ignition coils too

I had all plugs replaced as had not been done for 14 years. Car had 41,000 miles on it as I am original owner. Two weeks after new plugs, car started rough idle so took it back in and it was two coils gone bad. When changing plugs, don't forget to replace the boots too
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  #11  
Old 12-15-2015, 05:48 PM
u.nanimous u.nanimous is offline
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Location: SE Michigan
 
Join Date: Oct 2014
Posts: 2,174
Mein Auto: 1999 740iS, 2001 330xi
Quote:
Originally Posted by yitbos92 View Post
Thankfully this post hasn't disappeared. My car has been starting to do that as of the last couple of weeks. Idles rough as a cob when at a stop light and holding the break, and has some major hesitation when pushing the throttle from a dead stop. I have a new set of plugs for it, might try swapping those out this weekend and see if there's any oil in the plug holes like GLHExorcist mentioned.
No codes? If it is throwing misfire codes I'd start by swapping coil packs.
Did you get NGK plugs?
How's your MAF/TB/ICV?
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  #12  
Old 12-16-2015, 06:21 AM
yitbos92 yitbos92 is offline
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Location: Roseville, MI
 
Join Date: Nov 2014
Posts: 78
Mein Auto: 1998 740iL
Quote:
Originally Posted by u.nanimous View Post
No codes? If it is throwing misfire codes I'd start by swapping coil packs.
Did you get NGK plugs?
How's your MAF/TB/ICV?
Due to some home wiring for installation of an aftermarket radio, my OBD plug doesn't connect to anything according to the people at AutoZone.... they can't even get a reading that the car is running when they turn it on.

Yes on the NGK's
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  #13  
Old 12-16-2015, 05:45 PM
u.nanimous u.nanimous is offline
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Location: SE Michigan
 
Join Date: Oct 2014
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Mein Auto: 1999 740iS, 2001 330xi
How about the pacman port under the hood?
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  #14  
Old 12-16-2015, 08:09 PM
yitbos92 yitbos92 is offline
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Location: Roseville, MI
 
Join Date: Nov 2014
Posts: 78
Mein Auto: 1998 740iL
Quote:
Originally Posted by u.nanimous View Post
How about the pacman port under the hood?
That one I am unaware of..... Got a picture? I know my old 325E had an OBD I plug in under the hood but it was right out in the open....
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  #15  
Old 12-16-2015, 10:25 PM
u.nanimous u.nanimous is offline
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Location: SE Michigan
 
Join Date: Oct 2014
Posts: 2,174
Mein Auto: 1999 740iS, 2001 330xi
Hmm, I wonder if this is another yearly change...

In mine it is a 20 pin round connector attached to the passenger wheel well. When you unscrew the cap you'll see 20 pins and in the center is a little post shaped like pac-man.

Use google for images of "bmw e38 under hood pacman dlc".
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  #16  
Old 12-22-2015, 06:57 AM
Xlr8tin Xlr8tin is offline
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Location: NashVegas
 
Join Date: Oct 2013
Posts: 48
Mein Auto: 2000 740i M-Sport
Having one from brand new or something that has had it from new is the best way to go. Getting them used for 2K is a nightmare as they have too many issues when not upkept. Mine has been a nightmare, but I love driving itm and they look amazing
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