SL/R129: help diagnosing a particular coil pack
Thread Starter
Almost a Member!
Joined: Jan 2007
Posts: 71
Likes: 0
1997 SL500, 1994 Impala SS on steroids, 2007 MV Agusta Brutale 910R
help diagnosing a particular coil pack
I know my car needs a coil pack, it will stumble at idle occasionally and once threw a code stating there was a misfire, but im not sure which cylinder it is.
Is there some sort of a simple method of spotting the bad coil, or do i HAVE to plug it into the diagnostics machine and check the ohm readings?
Is there some sort of a simple method of spotting the bad coil, or do i HAVE to plug it into the diagnostics machine and check the ohm readings?
Member
Joined: Nov 2001
Posts: 217
Likes: 0
From: Fort Worth, Tx
97 SL500
I can't help you diagnose but I can share my experience with you. I had one go bad so the shop was able to immediately determine which one and replace it BUT less then 100 miles later another one went bad so we replaced the rest of them. The tech told me the dealer he worked for would only replace all of them at once b/c a coil pack going bad can take out DME which is considerably more expensive to replace then all 8 coil packs. I don't if how common that is but it is believable.
Thread Starter
Almost a Member!
Joined: Jan 2007
Posts: 71
Likes: 0
1997 SL500, 1994 Impala SS on steroids, 2007 MV Agusta Brutale 910R
I can't help you diagnose but I can share my experience with you. I had one go bad so the shop was able to immediately determine which one and replace it BUT less then 100 miles later another one went bad so we replaced the rest of them. The tech told me the dealer he worked for would only replace all of them at once b/c a coil pack going bad can take out DME which is considerably more expensive to replace then all 8 coil packs. I don't if how common that is but it is believable.
Member
Joined: Nov 2001
Posts: 217
Likes: 0
From: Fort Worth, Tx
97 SL500
The DME is the engine computer. There are many different references to this device and for some reason DME is what sticks in my head, as opposed to ECU or other names that I've heard.
Newbie
Joined: Sep 2007
Posts: 2
Likes: 0
From: Rancho Belago, CA
1994 SL500
Bad Coil
I had an experience with my 1994 SL500 which has two coils. One went bad. Had me fooled for a while. Replaced all of the plugs and wires but still had a miss. Traced the miss with a timing light to the four wires that went to one coil. Bought a new coil and the car ran great. The car lost power coming home one day. It would still do 90 mph even broke. It just wouldn't get to speed as fast.
Good Luck:
Good Luck:
