M104 coil pack life span
Thread Starter
Junior Member
Joined: Feb 2008
Posts: 52
Likes: 0
From: Atlanta
95 E320, 2002 E430
M104 coil pack life span
Hello from Atlanta! I had my 95 E320 coil packs and wires replaced about 34K mi. ago. Is there an average life span for the coils? Yesterday, the engine stopped at a red light and when I restarted it had a miss in it. Since it was low on gas (no red light), I refueled but the miss is still there. Assume it is a coil pack. Any advise would be appreciated.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,267
Likes: 170
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Hello from Atlanta! I had my 95 E320 coil packs and wires replaced about 34K mi. ago. Is there an average life span for the coils? Yesterday, the engine stopped at a red light and when I restarted it had a miss in it. Since it was low on gas (no red light), I refueled but the miss is still there. Assume it is a coil pack. Any advise would be appreciated.
Best was about 80K.
They sit right on top of the plugs and get very hot.
Lucky for us, there's no wires to worry about on m111.
Senior Member
Joined: Aug 2004
Posts: 263
Likes: 11
BMW E30. I've turned to the dark side.
coil packs for either engine are pretty reliable. what does have a high failure rate are the insulators under each coil - between the coil and spark plug. pull the plugs and you will usually see carbon tracks on the upper plug ceramic. if so, replace the plugs and the rubber insulators (like a plug wire, but directly off the bottom of the coil).
be careful of moving the wiring harness when pulling the coils, harnesses from that era are made of crapium. BTW a bad harness will also cause a misfire. see your local dealer to diag.
be careful of moving the wiring harness when pulling the coils, harnesses from that era are made of crapium. BTW a bad harness will also cause a misfire. see your local dealer to diag.
Thread Starter
Junior Member
Joined: Feb 2008
Posts: 52
Likes: 0
From: Atlanta
95 E320, 2002 E430
Thanks guys. I pulled all 3 coils and replaced one that had an ohmmeter reading across the coil. I did replace the plugs (and insulators at the encouragement of my parts guy). Just drove it around the block and it was fine. With 34k mi on them, my Bosch plugs were showing a gap of over 40 and the porcelain was eroded on most. The heavy white/tan crust on the electrodes tells me it's running too lean. Yes? If so, is this adjustment best handled by a diagnostic machine? Harness replaced at 60k mi by dealer (170K mi ago). Thanks again for your help.
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,267
Likes: 170
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
Thanks guys. I pulled all 3 coils and replaced one that had an ohmmeter reading across the coil. I did replace the plugs (and insulators at the encouragement of my parts guy). Just drove it around the block and it was fine. With 34k mi on them, my Bosch plugs were showing a gap of over 40 and the porcelain was eroded on most. The heavy white/tan crust on the electrodes tells me it's running too lean. Yes? If so, is this adjustment best handled by a diagnostic machine? Harness replaced at 60k mi by dealer (170K mi ago). Thanks again for your help.
