Just a guess (with the same engine in my E39 and having the experience
twice), but BMW's supplier provided a large batch of bad coils which have
failed regularly. Only cure is to go to a dealer (preferred ... I think
they should replace as a good will fix, it was a recall item) or indy
mechanic to read the codes and replace the coils. Even if its not coils,
the only way to diagnose is through an OBD code dump.
If it is a coil, you can just replace the effected coil(s), but the latest
bulletin is to replace all six. Of course, if its your nickel, you might
want to just go after the bad one and spread the cost of replacement over
time. OBTW, if you determine which coil, it's about a 15 minute DIY.
R / John
O2 sensor on the way out?
How old is the car and what milage has it done?
Had a similar problem two months ago (also 330ci e46) and it cost an
arm and a leg to fix - throttle control wiring had a high resistance.
Hope it's the sensor!
It's actually my friend's ride and he's got no scanner with him. Rang me
this morning and just wanted to see if it's safe to drive.
On 8/31/07 3:34 PM, in article
Okay, but the "leads" are part of the coil pack, they are not wires. They
can not be not connected, but they can be physically broken/burned to a
crisp. If this is the case, one must remove the coil to find out.
The "control wires" leading to the coils are not bullet proof, but they are
protected. I seriously doubt any damage to these wires, especially on an
E46. I'm not sure the first year of the 330, but my recollection is around
2005. This makes the car about 3 years old at this point. Surely the wires
will survive 3 years.
But still, one must pull the plastic cover off the top of the motor and get
close to the coil pack(s) to investigate this.
There is nothing the OP can do from here without pulling codes first. Well,
there is nothing he can do with any degree of certainty ... He can poke
around and hope, I suppose.
Just talked to a BMW master tech on a forum, he also reckons the coil pack
as he has done quite a few with similar symptoms. Let's see what code he'll
get when he visit the dealership coming Thursday (earliest). He's in London
so he has to book the car in and pays a premium just for pulling the code.
On 9/2/07 4:19 PM, in article zwACi.4831$3R5.998@trnddc05, "Jeff Strickland"
For less than the cost ot pay the dealer to pull codes, you can buy the scan
tool and pull codes yourself. TYhen, you will have the scan tool and can
pull codes on any '96 and later car or truck. (Since you said you are in
London, you may have different rules as they apply to the OBD II
In any case, this is data that should be available to you from the OBD (On
Board Diagnostic) system, you can buy the tool that pulls the data for less
than it costs to pay the stealership to pull it.
I just bought my second vehicle that is a post-'96 model, I will be buying
the scan tool from my local auto parts store as soon as either of them turn
the Check Engine light on.
You may have seen another on this thread that said there was a recall on
your coil packs. Be sure to investigate this before you pay for these parts.
His car is the Z4, but the motor is the same and the recall ought to apply
I had a similar problem on my E46 325i. The problem
was the ignition coils. They were replaced under warranty.
I had the car towed to the dealer back then, but was told
it was OK to drive (although there would be significant
loss of power).
Of course, that may not be the problem in this case.
The possibilities are endless. What you need to do is pull the trouble
codes. This is easy and free at Autozone. If you are in California, you can
visit an Autozone store, where they will put the scan tool on your credit
card and you take the tool home with you. After pulling the codes, you
return the scan tool and Autozone puts a Full Credit for the previous
"purchase" back onto your card, making the tool free to use.
There is a data port along the bottom edge of the dashboard that you plug
the scan tool into. Once the scan tool is connected, set the Igniton Switch
to ON but not START, and the codes that are stored will be displayed. Come
back here with the code list and we should be able to help you determine
what the repairs needed will be.
I like this link for diagnosing the codes ...
Once you pull the codes and jot down the list, you can reset them --
directions are on the scan tool. After you start the car and it runs poorly
and the Check light comes on again, yuou can repeat pulling the codes, and
this will tell you what the actual problem is. (Codes can be stored from
months ago that are truely transient problems that have nothing to do with
the price of beans today, so the second pull of codes will give a code that
matches one from the first list, this will be the actual problem and all of
the others are likely to be old and of no consequence.)
If you are outside of California, I do not know if Autozone will do the
same -- allow you to leave the store with the scan tool. You can purchase a
scan tool for less than BMW charges for the service to extract the codes
though. And, if the problem is one that you can fix at home, the scan tool
is a good buy, but if the problem requires dealer service (or equivelent),
the education is probably worth the cost of the tool. The scan tool is not
unique to your car, you can use it on any 1996 or later make or model
automobile or light truck.
By your description -- runs rough at idle -- my money is on a bad ignition
coil. Your car uses a separate ignition coil for each spark plug. Along the
top of the motor you will see two round plastic plugs, pop these out with a
small screwdriver -- be careful to not brake them. This allows the entire
top cover of the motor to be lifted out. Under this cover, you will find the
coil packs with the spark plugs immediately below them. The coil packs are
held on with two 10mm nuts, and the spark plugs take the standard 5/8"
(15mm?) Spark Plug socket.
If this is the problem, the cost of the scan tool and a coil pack will be
less than the cost of the service call at the dealership.
If you are new to this sort of thing, I suggest you get a friend that is not
new to it to help guide. Reward the friend with a 6-pack after the job is
done. There are common things -- anti-sieze compound -- that should be done
with installing plugs that one familiar with this sort of thing should
already know, and which if you are not aware of can create problems down the
road. The work is easy if it is what I suspect is true, but if not done
right, you can shoot yourself in the foot.
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