All,

On 10/20/09 I brought my car into the dealer for a CEL that was intermittently occurring. After I believe 18 start-ups the CEL resets and goes away however the CEL in a matter of a few days resurfaced. First time, the dealer found codes 745 and 2091 and was unable to reduplicate the failure. They cleared the CEL and returned the car to me since it was operating in factory specifications. Not even a week later driving home from the office I see once again the CEL. Again I bring it to the dealership hoping this time it will be resolved. This was their findings.

Intake leak due to gaskets. Perform short test code 0754 & 2091 for lean mixture. Check actual values were in spec until spraying with leak detection spray the injector timing went off scale. Tried to smoke test as well not conclusive. Spoke with shop foreman & agreed was intake gaskets to start. R&R all tubes & covers with air filter housing to R&R intake manifold to replace gaskets & bolts as per WIS. Torque to spec return all parts retest for leak as before at manifold no change good to go.

This Saturday I went to pick up my car at the dealership and after dropping $440 for B service, I went on my way. I would say maybe not even 10 miles I was on RT 80 where I got on the throttle and there she was like a nasty pimple the CEL. Just a little background on my car. I have one of the first 09's to be produced (6/08 production date) and my car is stock except for my the charcoal filters removed. Now here is my situation. My SA and I have a good relationship and I explained to him my charcoal filters are removed before hand. However this time he said its possible that maybe with the change in climate (temp dropping in NJ/NY area) things are going out of spec. I told him as calmly as I could that I pulled these filters over 4-5 months ago and that I seen many owners pull theirs across the M156 range. He also told me that he didn't alert the tech that the filters were removed, however I quickly countered and told him that when he was working on the intake manifold it would been clearly obvious they were missing. I asked him why didn't they do an ECU reset and he said they should have to readjust any specs. It just baffles my mind that out of all the cars with a M156 engine that are highly modified my car would throw a CEL for no charcoal filters with the stock air filters! It should be noted that I had a repeat CEL issue when I first got the car back in August of 2008 which turned out to be a defective purge valve. I wonder if maybe this problem has returned? Trying to stay calm, cool, collective gents but if my SA comes back and said this situation is because of the charcoal filters I will lose it.

 

same crap happened with my car..valves valves valves..purge valves..leaks and etc..i ended up getting my car lemond'

 

I just went over 20K on the clock last night so that would rule out the lemon law. My main issue is they are going to try and pin this on me for removing the charcoal filters. However I'm pretty confident that there is something else wrong with the car because again I been driving with no charcoal filters for about 5 months now almost.

 

I remember reading the thread about removing the charcoal filters. "Free Horsepower" by removing something that was put there for a specific reason. Cars in the Northeast and California cars,IIRC are mandated to have them to prevent hydrocarbon pollution from escaping from the intake manifolds when the car is shut off. Theres no doubt that they appear to choke the incoming air but you'd think the AMG engineers wrote the map for the ECU with the filters in place and by removing them-is it possible the ecu is fooled and can't adjust the mixture rich enough to take advantage of the newly found airflow? It seems like most people reporting CEL's after airbox mods like removing the charcoals or putting in K&N filters state it happens at high speeds/high engine loading where a lean mixture could hurt the motor? Hence the CEL and associated codes.

It sounds like your service dept. really tried to fix the problem.Some cars did indeed need repairs due to vacuum leaks. Apparently your car did indeed have an issue. Fact is-if those filters do indeed give you more power because they let in more air-then more fuel is needed and the ecu can only adjust the mixture so far. The Magnusson-Moss act can only protect you so far-technically you "altered the factory design" by removing the filters.The next step is the dealer or regional rep saying the problem was a direct result of that mod. It is what it is. If the dealer has something to hang their hat on to deny a warranty claim-they'll use it. Is it worth the risk not putting them back in?

Its your car and you do what you want. Alot of guys are modding the hell out of the C63 and making BIG time HP gains and without a doubt, going faster and having more fun. But sooner or later somebody is going to really find out the limit and have to PAY for a new motor. There are more STEALERS than Dealers. Good Luck.

 

Arclight338 appreciate your response, and you make some valid points however I like to add the following. I have driven the car for almost 5 months now without these filters and I have driven very hard also with NO CELs. To add further when I saw the first CEL the car wasn't at WOT just normal daily cruising. Continuing, the tech when removing the intake manifold obviously removed the air box and unless he was sleeping saw, the charcoal filters weren't in place. I wouldn't be surprised for such a large dealership they must seen a bunch of M156 engines with the filters removed. When I first recieved delivery of this car I through 3 CEL's in the first month of ownership and that was with nothing done to the car. I'm just looking at the feedback here from the forum and I drawn a few conclusions. The only CEL's reported when removing the charcoal filters was also when the air filters were replaced with K&N filters. These CEL appeared very quickly not 5 months after removal. Also a variery of CEL have been thrown for Cam sensors, purge valves. Cosidering I am an engineer my main concern is my car, the last two times wasn't in the right hands. During any trouble shooting process one tends to learn by trial and error aka replace a bunch of parts and see if that fixes the situation. With that being said its obvious that method didn't work in my car. It just hard to digest with all the highly/midly modded C63's on this forum only my car would through a CEL for charcoal filter removal when the car is completely stock. Again I might be jumping to conclusions with all this but I am eager to see what happens, the 3rd time around.

 

There are plenty o 63's runnin round minus filters minus cel.
Likely a failed sensor. The filters are for emissions and they do not create enough air flow to mimic a turbo or sc or even a 40 degree day. The variance would in no way be enough to throw a light.

How can you explain the hundreds of filterless cars not having this trouble?

Put the filters back in and take it to a different dealer to fix the real problem.

 

I think it can be explained by difference in the ECU coding. NO ONE knows EXACTLY how all the ECU's are coded-except for AMG and Bosch. Depending on build date-things can and do change. I'm not saying removing the filters will create a CEL-BUT MikeG has one.They fixed the intake leak. Its still not right-he is beyond Lemon Law relief-so he has to and SHOULD have it fixed under warranty. You can't just ASSUME though that removing the filters doesn't affect anything.

My point is,why chance giving them ANY reason to bust ***** and NOT fix the issue. That is just from the warranty standpoint.

Juicee63- you say they don't create enough airflow to mimic a turbo or sc-who said it did. But some claim it gives enough HP to feel it in the seat of the pants-if that is true and if the engine IS making more horsepower the fuel has got to come from somewhere.And if the ecu doesn't supply enough fuel when the engine needs it---- it is clear SOMETHING is wrong-put it back to the way it WAS from the factory and let them fix it.

 

It is negligible , I am 100% confident the filters have absolutely nothing to do with the CEL.

They do not need to be in the air box and are placed there so the cars can meet US emission standards. hp gains can be zero and usually range from 0-5hp ewith one car showing an 18 hp gain , lol I was there trhe day the car dynoed raced him and waxed him in my stock 63 which dynoed 30 hp less LOL

 

Cory@Kleemann stated that these cars ECUs can adapt with their new throttle bodies on them without a tune so I doubt the filters would make as much of an impact on the air coming into the vehicle. Hopefully they figure it out goodluck!

https://mbworld.org/forums/3764955-post31.html

 

Update:

Spoke to my SA today and he said that he is having a master diagnostics tech look at the car. With that being said today the tech reported back to him the temp sensor on the back of the intake by the firewall wasn't connected. However they are still going to do a full inspection to see if there are any other issues. I believe the following to be true. The charcoal filters being removed have nothing to do with this CEL because they been gone from the car for 5 months. Any issues I read about CEL's related to charcoal filter removals almost immediately surface. However with that being said I will see what the there findings are.

Does anyone have any feedback on this situation if I was to take the car back and have the ECU flashed with a tune would that eliminate a "running lean" scenario considering the diferent A/F ratios? Obviously this is only applicable if there is nothing mechancially wrong with my car.

 

If you only gain a couple of HP with the filters removed, why not just put them back in? Are there other noticeable differences, and is it worth it?

 

The same thing happened to my SL63 (engine was running lean both banks). Actually I lost hp from removing the charcoal filter. Now I have them on the car and its running perfect.

 

Mike, any updates on this? Just curious.

 

I'd be interested to hear what happened too. I have the VRP air filters and i removed the charcoal filters after the 1000 mile break-in. I've had no CEL at all. I have one of the early 2008 models, received car in May.