Check engine light from K&N air filters.
08-07-2010, 11:17 PM
#1
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Check engine light from K&N air filters.
My car is throwing a Left and Right bank lean code (CEL). I have reset it and it came back on again after a few hours.
I have a Renntech stage 2 tune.
Anyone else running lean after installing after market air filters???
I have a Renntech stage 2 tune.
Anyone else running lean after installing after market air filters???
08-07-2010, 11:44 PM
#2
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There have been a few people that experienced this. I believe the fix is making sure the box tops are on even and tight and the rubber hoses are snuggly on the box tops. I am assuming the MAFs are plug into the connector?
What happens when you put the stock filter and charcoal back on?
What happens when you put the stock filter and charcoal back on?
08-07-2010, 11:48 PM
#3
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2009 C63 Silver, k&n with charcoal's removed
I would love to get some feedback too, below is the text from my post.
Hi all, I have K&N filters and charcoal filters removed in my car and getting the dreaded lean error. I have reset ecu and now have cleared the lean error for like 3 days in a row.
I have been reading the searches here and get mixed results, some have the error and other have none.
I did not over oil! This is my 5th car with k&n's and did recheck the seating of them so that they were not leaking.
I hope to get some help and or if did not search right a link to help me.
Thank you all.
09 c63 stock with k&n and charcoal's removed
I have been reading the searches here and get mixed results, some have the error and other have none.
I did not over oil! This is my 5th car with k&n's and did recheck the seating of them so that they were not leaking.
I hope to get some help and or if did not search right a link to help me.
Thank you all.
09 c63 stock with k&n and charcoal's removed
08-08-2010, 12:47 AM
#4
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No, you are not dreaming. I also had that same issue with just K&N filters and the charcoals removed. I was getting lean codes as well and it happened several times.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
08-08-2010, 10:09 AM
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2009 C63 Silver, k&n with charcoal's removed
I take it you are running stock filters again? I am going to try k&n's with charcoal's.
No, you are not dreaming. I also had that same issue with just K&N filters and the charcoals removed. I was getting lean codes as well and it happened several times.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
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08-08-2010, 10:11 AM
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2009 C63 AMG, 2006 porsche 911 carrera S conv., 2014 Jeep GC
I had the same issues when I removed charcoals and put K&Ns in. Car threw codes (running lean) and actually once in a while hesitated. Ended up putting stock filters back in (still charcoal removed) and car ran great without issues for 10000miles.
Just got my Eurocharged tune and thaught I would try to put K&Ns back in.
So far no issues (only 1 week on car though), I guess the tune is helping here.
Just got my Eurocharged tune and thaught I would try to put K&Ns back in.
So far no issues (only 1 week on car though), I guess the tune is helping here.
08-08-2010, 01:49 PM
#9
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I would have thought you would have felt something. The Renntech box looks to be the best out there with those revised and smoother runners.
08-08-2010, 02:27 PM
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996tt Protomotive, C63
08-08-2010, 02:40 PM
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996tt Protomotive, C63
Another thing I think the lean from K&N might not be from flowing lot more air. Engine with OBD II could adjust/compensate to -+10%.
This is what I think. Oil from k&n might get/evaporate in mass air flow(Maf). Maf now reads lower value cause it is lightly coated. ECU cuts fuel little accordingly. Now your engine is running lean. (cause same amount of air going in but Maf thinks it is less.)
If you have scanner, check if LTFT(long term fuel trim) at idle is + more than 10%.
This is what I think. Oil from k&n might get/evaporate in mass air flow(Maf). Maf now reads lower value cause it is lightly coated. ECU cuts fuel little accordingly. Now your engine is running lean. (cause same amount of air going in but Maf thinks it is less.)
If you have scanner, check if LTFT(long term fuel trim) at idle is + more than 10%.
Last edited by aroonkl; 08-08-2010 at 02:44 PM. Reason: add
08-08-2010, 03:04 PM
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'09 C63 AMG
It's not the filters; it's almost certainly some sort of leak when you put the air boxes back together. I had this issue just after I installed my BMC air filters (and had my charcoals removed previously with no issues). I took it to RENNtech, but they couldn't find the leak. So, I took it to my dealer, and guess what? I had a crack and a leak in the air intake manifold...they replaced it under warranty and I said goodbye to the "lean" codes. 
08-08-2010, 03:09 PM
#13
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1)I am driving at altitude
2)I am running 91 oct
3) I am running with very high temps
4)I am running in a very dusty area
All those 4 factors contribute for the car to run "weak". I have had the stock filter now for about 550 miles and no issues so far. My gas mileage got significantly worse though. The K&N filters for sure gave me better gas mileage.
08-08-2010, 09:11 PM
#14
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I have the K&N's and also had the CEL's afterward.. This may have already been said but you have to clean the mass air flow sensors. I used a small amount of carborator cleaner and the CEL's when away.. You will have to pull the mass air flow sensors out of the housing to clean them properly.
08-08-2010, 10:41 PM
#15
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I have the K&N's and also had the CEL's afterward.. This may have already been said but you have to clean the mass air flow sensors. I used a small amount of carborator cleaner and the CEL's when away.. You will have to pull the mass air flow sensors out of the housing to clean them properly.
08-08-2010, 11:20 PM
#16
I have the K&N's and also had the CEL's afterward.. This may have already been said but you have to clean the mass air flow sensors. I used a small amount of carborator cleaner and the CEL's when away.. You will have to pull the mass air flow sensors out of the housing to clean them properly.
http://www.amazon.com/CRC-05110-Mass.../dp/B000J19XSA
08-23-2010, 02:14 AM
#17
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I took the KN filters out and put the stock ones back in. Code is gone now.
I inspected the intake, there was no leaks to be found.
Took the MAFS out on each side, both were very cleaned, looked brand new so I left them alone.
I inspected the intake, there was no leaks to be found.
Took the MAFS out on each side, both were very cleaned, looked brand new so I left them alone.
04-02-2017, 09:17 AM
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2007 cls63 amg and 2002 s430
My 2007 CLS63 started to throw left bank lean code right after the removal of the charcoal filters and installation of K&N filters. But why the lean code on the left bank only and the right bank seems OK. Need the code gone for a E-test in Ontario, and really don't want to put the stock ones back in.
Brian
Brian
04-02-2017, 11:45 AM
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2012 C63;1971 280SE 3.5(Sold);2023 EQS 450 SUV 4 Matic (Wife's)
My 2007 CLS63 started to throw left bank lean code right after the removal of the charcoal filters and installation of K&N filters. But why the lean code on the left bank only and the right bank seems OK. Need the code gone for a E-test in Ontario, and really don't want to put the stock ones back in.
Brian
Brian
04-05-2017, 10:48 AM
#22
Member
Now, it took a week to notice this feel and there were a few unusual hard downshifts at stops but that cleared up. Am I wrong thinking the computer needed time to figure out the new configuration and MAF sensors?
TC
04-05-2017, 10:53 AM
#23
Super Member
I just put ROW boxes on. No codes and after a week of driving, it feels a bit more "willing" when I get into the throttle.
Now, it took a week to notice this feel and there were a few unusual hard downshifts at stops but that cleared up. Am I wrong thinking the computer needed time to figure out the new configuration and MAF sensors?
TC
Now, it took a week to notice this feel and there were a few unusual hard downshifts at stops but that cleared up. Am I wrong thinking the computer needed time to figure out the new configuration and MAF sensors?
TC
My car took about a day to adjust and then it livened things up a bit. I noticed more throttle response more crackling and pops and even a more aggressive cold start. I have the V6 tune and I think the ROW boxes work well with it. I have heard that the ecu needs to "learn" to adjust when you make changes.
01-16-2020, 05:09 PM
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2012 C63
No, you are not dreaming. I also had that same issue with just K&N filters and the charcoals removed. I was getting lean codes as well and it happened several times.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
I put the stock filters and I had the dealer reseting the CEL when I took it for service A.
It is not about the oil in the filters, it is about the flow going through and the AFRs.
