Terminal miss-fire issue....again
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From: Central Florida
2013 Chevy 427 Torch Red
Understand that if you mod your car and develop a problem like this where the root cause is not obvious, the dealership wants to blame the mods rather than investigate the way they would on a stock car. It is perfectly reasonable to them to blame the headers or tune rather than admit that this setup has worked fine for more than 2 years and is working fine on hundreds of other C63's as well. With that I have ordered a new ECU and once it is installed with stock files, they are willing to seriously troubleshoot. There is a real possibility that the ECU itself is causing the problem which I will know if the problem is solved by installing a new one. According to the head AMG tech (who has been very cool about the whole thing) he has seen two ECUs that started causing problems and would not allow stock files to be reloaded. Of course the warranty for the ECU was voided due to it being removed and tuned. I will update once we know more.
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Understand that if you mod your car and develop a problem like this where the root cause is not obvious, the dealership wants to blame the mods rather than investigate the way they would on a stock car. It is perfectly reasonable to them to blame the headers or tune rather than admit that this setup has worked fine for more than 2 years and is working fine on hundreds of other C63's as well. With that I have ordered a new ECU and once it is installed with stock files, they are willing to seriously troubleshoot. There is a real possibility that the ECU itself is causing the problem which I will know if the problem is solved by installing a new one. According to the head AMG tech (who has been very cool about the whole thing) he has seen two ECUs that started causing problems and would not allow stock files to be reloaded. Of course the warranty for the ECU was voided due to it being removed and tuned. I will update once we know more.
Thread Starter
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From: Central Florida
2013 Chevy 427 Torch Red
The new ECU with stock tune files was just installed and the car continues to misfire after about 5 minutes of driving. The dealer is not willing to look any further into the issue unless I agree to pay time and material while they blindly replace every thing until it starts working again. They claim having headers on the car prevents the diagnostic equipment from working as it continues to point to the exhaust system as the root cause. They offered to replace all the spark plugs and switch coil packs from the left bank to the right for the value price of $700. I politely declined and drove the car home. The non tuned ECU does not like the headers AT ALL and I put the old ECU back in to drive it. The misfire is still there but mostly just at idle and during acceleration. At steady speed you don't know it's having any issues. I have the new ECU on it's way to Andy and once it is back the car is going to the shop where Keith has had all the experiments conducted on his motor. Jerry, the shop owner has been deep into the 156 and should be able to resolve the problem.
Big lesson here is that once you make any visible modifications, be prepared for the dealer to wash their hands of any problems that you may have with the motor and transmission. I knew that going in but I was surprised by their inability to diagnose issues in a modified environment. I am not going to pay MB rates for a blind man to find the problem.
Big lesson here is that once you make any visible modifications, be prepared for the dealer to wash their hands of any problems that you may have with the motor and transmission. I knew that going in but I was surprised by their inability to diagnose issues in a modified environment. I am not going to pay MB rates for a blind man to find the problem.
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C63
I hope this issue gets resolved asap. I would check with an independent MB shop to see how much they quote for spark plug and coil pack replacement.
Please keep us posted.
Please keep us posted.
Last edited by _AMG_; Jun 22, 2011 at 04:14 PM.
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*BANGSHEAD* 
I wonder how having a more efficient exhaust is causing a misfire? I'm not a mechanic, but wouldn't that be on the intake/ignition side of the motor that is causing these issues or a sensor that may affect timing? You still have your O2 sensors, right?
I wonder how having a more efficient exhaust is causing a misfire? I'm not a mechanic, but wouldn't that be on the intake/ignition side of the motor that is causing these issues or a sensor that may affect timing? You still have your O2 sensors, right?
Last edited by Sincity; Jun 22, 2011 at 04:19 PM.
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Thread Starter
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Joined: Oct 2008
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From: Central Florida
2013 Chevy 427 Torch Red
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From: Central Florida
2014 Audi RS7
Howard,
We can do the plugs and coil packs if you want to. They are easy.
No matter the case Jerry will find the culprit.
He knows this motor backwards and forwards and has done the build many times. He's one of the few that knows what he's doing on these cars. If you need any work done I highly recommend him. I know we are in Florida but I know he's already had M156 motors shipped to him for rebuilds so he knows the game. He also knows the trannies and can help there as well.
He custom built the diff cooler for me and has done many of my modifications. For the nitrous build I would recommend Macedo Motorsports. Larry is great with after market stuff. He usually works on Vipers and exotics. Just a plug for my two very hard working mechanics if any of you need a good mechanic to do your stuff!!
We can do the plugs and coil packs if you want to. They are easy.
No matter the case Jerry will find the culprit.
He knows this motor backwards and forwards and has done the build many times. He's one of the few that knows what he's doing on these cars. If you need any work done I highly recommend him. I know we are in Florida but I know he's already had M156 motors shipped to him for rebuilds so he knows the game. He also knows the trannies and can help there as well.
He custom built the diff cooler for me and has done many of my modifications. For the nitrous build I would recommend Macedo Motorsports. Larry is great with after market stuff. He usually works on Vipers and exotics. Just a plug for my two very hard working mechanics if any of you need a good mechanic to do your stuff!!
Thread Starter
MBWorld Fanatic!
Joined: Oct 2008
Posts: 1,521
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From: Central Florida
2013 Chevy 427 Torch Red
Howard,
We can do the plugs and coil packs if you want to. They are easy.
No matter the case Jerry will find the culprit.
He knows this motor backwards and forwards and has done the build many times. He's one of the few that knows what he's doing on these cars. If you need any work done I highly recommend him. I know we are in Florida but I know he's already had M156 motors shipped to him for rebuilds so he knows the game. He also knows the trannies and can help there as well.
He custom built the diff cooler for me and has done many of my modifications. For the nitrous build I would recommend Macedo Motorsports. Larry is great with after market stuff. He usually works on Vipers and exotics. Just a plug for my two very hard working mechanics if any of you need a good mechanic to do your stuff!!
We can do the plugs and coil packs if you want to. They are easy.
No matter the case Jerry will find the culprit.
He knows this motor backwards and forwards and has done the build many times. He's one of the few that knows what he's doing on these cars. If you need any work done I highly recommend him. I know we are in Florida but I know he's already had M156 motors shipped to him for rebuilds so he knows the game. He also knows the trannies and can help there as well.
He custom built the diff cooler for me and has done many of my modifications. For the nitrous build I would recommend Macedo Motorsports. Larry is great with after market stuff. He usually works on Vipers and exotics. Just a plug for my two very hard working mechanics if any of you need a good mechanic to do your stuff!!
Eight new Denso iridiums are on my desk. Perhaps after cars n cafe we could go ahead and change plugs, switch sides on all the coil packs (I also have a tester) and clean the MAF sensors. We could put the car up on Jimmy's rack and visually inspect the o2 sensors as well.
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Anything W/4Wheels
Sry to hear. You issue with the dealer plain sucks!!!
Could you take the exhaust off and put the stock tune on and then go to another dealer?
That would be u best bet for u pocket.
Could you take the exhaust off and put the stock tune on and then go to another dealer?
That would be u best bet for u pocket.
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From: NY
See Sig
Carful the ethics police are going to hunt you down now...
Sadly im sure they share info and have added the information to his VIN already.
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Howard,
I see both bungs on the MHP headers. It would be great if you can just swap parts with Keith and rule out each item one-by-one rather than play the experimental game with the dealer commiting you to buy each part.
I see both bungs on the MHP headers. It would be great if you can just swap parts with Keith and rule out each item one-by-one rather than play the experimental game with the dealer commiting you to buy each part.
Thread Starter
MBWorld Fanatic!
Joined: Oct 2008
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From: Central Florida
2013 Chevy 427 Torch Red
Thanks Keith,
Eight new Denso iridiums are on my desk. Perhaps after cars n cafe we could go ahead and change plugs, switch sides on all the coil packs (I also have a tester) and clean the MAF sensors. We could put the car up on Jimmy's rack and visually inspect the o2 sensors as well.
Eight new Denso iridiums are on my desk. Perhaps after cars n cafe we could go ahead and change plugs, switch sides on all the coil packs (I also have a tester) and clean the MAF sensors. We could put the car up on Jimmy's rack and visually inspect the o2 sensors as well.
Very sad that the MB tech's were so focused on the modifications that they didn't bother to pop out a plug and take a look. Can you say computer dependant.
Car is GREAT now, likes the Denso plugs and the MHP tune.
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Vath ML63 Brabus C63 SL63 CLK63BS C63BS
Thats quite an amzing story Hhughes, checking spark plugs seems like a simpole first step and yet the so-called experts completely missed it. I am gobsmacked at their incompetence. You are so right, if the computer doesnt diagnose it therefore cant be a problem, makes me wonder why these guys ever wear coveralls and rather than just a suit and tie with a pocket protector
Last edited by Maverick1975; Jun 27, 2011 at 09:32 PM.
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From: Sarasota FL
2020 E450 Wagon
How many miles on the original spark plugs? Did you measure the gap difference new/old? A slightly cooler heat range plug might be in order should you rack up much track time.
Last edited by GermanCars; Jun 27, 2011 at 09:37 PM.
Thread Starter
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From: Central Florida
2013 Chevy 427 Torch Red
Here they are $13.50 each. Every other site was charging $23-$25 per
Thread Starter
MBWorld Fanatic!
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From: Central Florida
2013 Chevy 427 Torch Red
These Denso's are supposed to be slightly cooler and they are pre-gapped at 0.43" They had 26,000 miles,many track days and plenty of race fuel used. The same bank had a cam position problem at an earlier time which may have hastened the electrode fouling on those specific plugs.
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See Sig
Moral of the story: Never be "too busy" to take the time and check the obvious.......Guess which ones came from the problem bank
Very sad that the MB tech's were so focused on the modifications that they didn't bother to pop out a plug and take a look. Can you say computer dependant.
Car is GREAT now, likes the Denso plugs and the MHP tune.
Very sad that the MB tech's were so focused on the modifications that they didn't bother to pop out a plug and take a look. Can you say computer dependant.
Car is GREAT now, likes the Denso plugs and the MHP tune.
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From: 43°38'N / 79°52'W
EuroCharged 2012 C63 BS Coupè
http://sparkplugs.com/results_app.as...1&AAIA=1443250
Here they are $13.50 each. Every other site was charging $23-$25 per
Here they are $13.50 each. Every other site was charging $23-$25 per
Last edited by NORTH 44 C63; Jun 27, 2011 at 10:10 PM.
