SL55/63/65/R230 AMG: V-12 Coil Pack problems
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
V-12 Coil Pack problems
I've been following a thread just below this about Monstra from Australia and his problems with his car after a Eurocharged tune. I have the exact same problem. the car is a '05 S600 with a recent Eurocharged tune. A few weeks after the tune I got a CEL for a misfire. I cleared the code but it came back on and off, then more frequently, usually after a night in the garage. Recently I have not been able to clear the code. EC was a help and created a new program, with the same results. Then we put the stock tune in, again with no luck. Then I spoke to a guy in Calif. who rebuilds your coils. Since the codes were for all cylinders the transformer feeding the coils was a suspect. I opened the transformer and it was not burned or obviously bad which the guy said was about 99% indication of no damage.Finally i bought and installed a new coil today. Again no luck, same codes same misfires 1/2 and engine. I'm really lost. Any one have any ideas or suggestions. I don't have DAS but have two other diagnostic programs. I'm almost ready to go to the dealer for the first time in three MB's.
Member
Joined: May 2013
Posts: 230
Likes: 27
From: Maryland
MBs: SL55, GLK350
Have you tried reflashing the vehicle/ECU back to stock? See if the problem still occurs.
The tune itself is not likely the problem, but as the spark (and fuel) tables are remapped, ignition advanced, boost increased, the coils have to work harder to arc the plug gap which will make a weak ignition system fail and misfire despite operating seemingly fine at stock performance level. Thus the problem shows up after tuning and the obligatory post-tune fun
Having fresh, properly gapped plugs is a great idea before installing a performance tune.
The tune itself is not likely the problem, but as the spark (and fuel) tables are remapped, ignition advanced, boost increased, the coils have to work harder to arc the plug gap which will make a weak ignition system fail and misfire despite operating seemingly fine at stock performance level. Thus the problem shows up after tuning and the obligatory post-tune fun
Having fresh, properly gapped plugs is a great idea before installing a performance tune.
Last edited by dRockSL55; Mar 12, 2016 at 12:33 PM.
MBWorld Fanatic!
Joined: Jan 2011
Posts: 1,181
Likes: 59
CL65
I realize the parts cost money, but the dealer will end up throwing parts at it AND charging alot for the labor. If you are getting codes for both banks change the ignition module, and why you are at it the other coil, assuming it's original. If it is its only a matter of time before failure. As mentioned plugs too if they weren't replaced recently and with the proper plugs. Despite no physical signs of failure on the ignition module it still sounds at fault.
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
All good ideas. All already done. The coils were new 30k miles ago replaced with new part numbers.
I understand the tune adds new stress and could even live with the results but there is more damage.
New plugs were installed with the new coil yesterday. NGK's come now at .7mm
Stock tune installed by EC and same issue. Their comments were it is not the tune but the coil.
EC installed new tune with less timing, same problem.
I checked wiring for proper ground.
Ignition transformer opened up and appeared OK no burned pieces.
Went to MB today and they will take car on Monday and diagnose only, for $200 and tell me results. Stay tuned (sic) for results.
I understand the tune adds new stress and could even live with the results but there is more damage.
New plugs were installed with the new coil yesterday. NGK's come now at .7mm
Stock tune installed by EC and same issue. Their comments were it is not the tune but the coil.
EC installed new tune with less timing, same problem.
I checked wiring for proper ground.
Ignition transformer opened up and appeared OK no burned pieces.
Went to MB today and they will take car on Monday and diagnose only, for $200 and tell me results. Stay tuned (sic) for results.
Senior Member
Joined: Jan 2012
Posts: 338
Likes: 15
SL65 AMG
Agree with RaceHorse, since you're getting both banks I'd look at the ignition module first then coil packs and plugs. Coils tend to foul soon after the added stress of an updated tune, just part of the game.
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
I didn't understand the replies to my original message. I just re-read my original post and saw why. the misfire is for all cylinders ON ONE SIDE. When I changed the coil on that side the codes still were there.
If I clear the codes, in the morning, which takes a few tries to clear, the car will start and run perfectly all day. I can then drive to normal temp, then start again numerous times, as long as the car does not sit till it completly cools off (overnite). I don't understand why I can get it to start by clearing codes, then start numerous times, until it sits overnite. Is some electronic part making contact hot and then shrinking overnite. But why will the codes clear in the morning then?? This is making me nuts.
If I clear the codes, in the morning, which takes a few tries to clear, the car will start and run perfectly all day. I can then drive to normal temp, then start again numerous times, as long as the car does not sit till it completly cools off (overnite). I don't understand why I can get it to start by clearing codes, then start numerous times, until it sits overnite. Is some electronic part making contact hot and then shrinking overnite. But why will the codes clear in the morning then?? This is making me nuts.
Trending Topics
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,011
From: Miami, FL
2003 CL 600
All good ideas. All already done. The coils were new 30k miles ago replaced with new part numbers.
I understand the tune adds new stress and could even live with the results but there is more damage.
New plugs were installed with the new coil yesterday. NGK's come now at .7mm
Stock tune installed by EC and same issue. Their comments were it is not the tune but the coil.
EC installed new tune with less timing, same problem.
I checked wiring for proper ground.
Ignition transformer opened up and appeared OK no burned pieces.
Went to MB today and they will take car on Monday and diagnose only, for $200 and tell me results. Stay tuned (sic) for results.
I understand the tune adds new stress and could even live with the results but there is more damage.
New plugs were installed with the new coil yesterday. NGK's come now at .7mm
Stock tune installed by EC and same issue. Their comments were it is not the tune but the coil.
EC installed new tune with less timing, same problem.
I checked wiring for proper ground.
Ignition transformer opened up and appeared OK no burned pieces.
Went to MB today and they will take car on Monday and diagnose only, for $200 and tell me results. Stay tuned (sic) for results.
MB World Stories
The Best of Mercedes & AMG
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
Partial Update: Left car at MB last nite, they called today and said that they are almost positive it is the ignition transformer controller. They will confirm tomorrow. I had no way to test this so the 200$ was money well spent (I hope). I can get a new one for 600$ and a 10 min install.
Final update tomorrow...
Final update tomorrow...
Super Member
Joined: Mar 2008
Posts: 586
Likes: 12
From: Phoenix AZ
2005 C55 AMG - 2018 340i - 2006 SL55 AMG - Sold
Your 2003 CL600 ran a 12.5 in the 1/4 stock? No mods? No flash? Really?
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
Almost final update: MB confirmed the diagnosis of the ignition transformer. I elected to let them provide and install it. this will cost me about 300$ more than if I take it home and provide and install. But... if they do it it is guarented to solve the problem or else I don't have to pay. If I do it and it doesn't fix the problem it is on me. I will pick it up on Sat. Think positive....
Thread Starter
Junior Member
Joined: Jan 2008
Posts: 34
Likes: 0
'05 S600
OK real final update. Problem solved. I got the car back from the MB dealer. The ignition transformer was replaced and the car now runs great and starts in the morning which was the major issue. The EC tune did not cause the failure. Coil pack was changed out for nothing. MB dealer charged me about 10% more for the part than the average internet price.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,011
From: Miami, FL
2003 CL 600
Yeah, on less than stellar tires and with an average launch, I had only had the car for 6 days and hadn't really got the launching down yet. They are very fast cars, on a sticky tire i'd say high 11's is a definite possibility.
MBWorld Fanatic!
Joined: May 2015
Posts: 4,037
Likes: 1,011
From: Miami, FL
2003 CL 600
OK real final update. Problem solved. I got the car back from the MB dealer. The ignition transformer was replaced and the car now runs great and starts in the morning which was the major issue. The EC tune did not cause the failure. Coil pack was changed out for nothing. MB dealer charged me about 10% more for the part than the average internet price.
