Hi, looking for some help here. '03 MC, MT, no mods. Drove car into garage. Battery died after daughter played in the car and helpfully left hazards going...charged battery overnight at 2A trickle,
(no jump). Got in, car recognizes key, plenty of crank, fuel pump runs, starting fluid does no good. There is power to the coil, but no spark at the plugs (which are new, and OEM). Checked every single fuse twice- all good. Reset computer, no change.
Car will fire a few times randomly on repeated, rapid, twists of the key, but no more than that. Any thoughts? Thanks!

 

interesting... new plugs...you say no spark to ANY of the plugs (and fuel is delivered and I assume you can smell the gasoline at the plugs), then sounds like the coil - but don't know how a battery rundown would cause that.

 

Oh, I should add, the OBD II returns no codes. This battery has gone flat a few times before, (don't ask), with no problems. Does the immobilizer affect ignition as well as fuel? (grasping at straws here). Thanks.

 

well if your getting no spark but your getting power to the coil id guess that its the coil its self. how many miles are on your coil?

 

111k+.

 

yeah id try a new coil pack, you can get a msd for like 89.00, not sure how much a oem costs.

 

Okay, bench tested the coil and get spark. Any other ideas out there? Does the dealer-installed OEM alarm system disable the ignition? Are the crank/cam position sensors durable? Thanks.

 

As I understand it, the alarm does disable the ignition system. But since I don't have it in my car, I can't confirm that. But I also think that the alarm does re-enable the ignition after after a few minutes. If the ignition is disabled, you would not get a spark, or the coil pack would not be working.

Have you dried using a different coil pack on your car? On one of my other cars, I recently had a coil pack go on me. It bench tested fine, but did not provide enough juice to start the car. I substituted another pack on it, and the car ran fine so it was the coil pack.

Good luck.

 

Has anyone else experienced a sudden, total coil pack failure? How about the immobilizer/ECU interface failing after a dead battery? As much as it galls me to do so, I'm afraid I'll have to trailer it to the dealer. ARRRRGGGH!!!!

 

Well, a local BMW dealer "aligned" the EWS & ECU, and presto! She runs. Could anyone hazard a guess as to why they would stop communicating just because the battery went flat? Very worrying, in my opinion. On the upside, the garage only charged me $ 45! Really decent of them, I thought.

 

no ideas, but good show!