CLK 200 Kompressor (M271 1.8L) Running rich and high CO emission
08-23-2023, 11:11 PM
#1
Newbie
Thread Starter
Join Date: Aug 2023
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
CLK 200 Kompressor 2003
CLK 200 Kompressor (M271 1.8L) Running rich and high CO emission
Hi!
My car recently failed a emissions test because of too high CO. The car seems to be running rich too. I have not noticed the car running worse/rough or smell from exhaust but fuel consumption feels exsessive. The car is throwing the following DTC codes: P0170, P0137, P0172, P0138, P0136, P0141. The P0170 (Fuel Trim Bank 1) and P0172 (System Too Rich) seem to be the ones that return when cleared. It seems the bank 1 sensor 2 is just throwing codes at random and they dont immediatly return. I have changed both o2 sensors about a year ago along with the vacuum line under the air box. I checked the connection box on downstream o2 (sensor 2) and it was very oily. I checked the readings from both o2 sensors and they seemed responsive when applying throttle etc. The readings I got from o2 sensor 1 was about 1V at idle and peak at 3.157 when giving it some throttle. For sensor 2 I saw 0.35V ish at idle and peak at 1V with some throttle. I also checked the MAF which read 2.4g/s at idle and got up to 14.5 with some baby revs. I have spent some time looking for another vacuume leak but no luck. Also ordered spark plugs.
Anyone experienced the same thing or have tips or any idea what to do next?
My car recently failed a emissions test because of too high CO. The car seems to be running rich too. I have not noticed the car running worse/rough or smell from exhaust but fuel consumption feels exsessive. The car is throwing the following DTC codes: P0170, P0137, P0172, P0138, P0136, P0141. The P0170 (Fuel Trim Bank 1) and P0172 (System Too Rich) seem to be the ones that return when cleared. It seems the bank 1 sensor 2 is just throwing codes at random and they dont immediatly return. I have changed both o2 sensors about a year ago along with the vacuum line under the air box. I checked the connection box on downstream o2 (sensor 2) and it was very oily. I checked the readings from both o2 sensors and they seemed responsive when applying throttle etc. The readings I got from o2 sensor 1 was about 1V at idle and peak at 3.157 when giving it some throttle. For sensor 2 I saw 0.35V ish at idle and peak at 1V with some throttle. I also checked the MAF which read 2.4g/s at idle and got up to 14.5 with some baby revs. I have spent some time looking for another vacuume leak but no luck. Also ordered spark plugs.
Anyone experienced the same thing or have tips or any idea what to do next?
10-28-2023, 10:34 AM
#2
Newbie
Join Date: Oct 2023
Posts: 1
Likes: 0
Received 0 Likes
on
0 Posts
2003
merhaba benim aracımda silkeleme sorunu vardı hava akışı metre (maf sensörü) değişikliği yaptım sonra P0172 arızası oldu daha sonra eskisini taktım birdaha P0172 arızası olmuyor sizde maf sensörünü değişip test edebilirsiniz
Last edited by alone; 10-28-2023 at 10:38 AM.
10-30-2023, 01:57 PM
#3
MBWorld Fanatic!
iTrader: (1)
Join Date: Nov 2016
Location: Maryland, United States
Posts: 4,594
Received 1,634 Likes
on
1,219 Posts
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Running rich could be a bad fuel injector since you covered the other stuff. And high CO levels could be an inefficient (bad) cat. Sensor 2 (post cat) being oily is a little confusing. The cat is supposed to run hot enough to burn off any oil.
A dirty/clogged fuel injector won't atomize the fuel enough for proper burn.
All the other codes point to sensor 2 being bad. Did you clear codes after you switched out the o2 sensors? They could be old codes. Did you replace the o2 sensors with OEM/OE/Genuine parts or aftermarket? Since Mercedes seem to be temperamental about anything electronic, I would stick with Genuine or OE parts. Are you in the US?
Or you could also have a bad catalytic converter.
A dirty/clogged fuel injector won't atomize the fuel enough for proper burn.
All the other codes point to sensor 2 being bad. Did you clear codes after you switched out the o2 sensors? They could be old codes. Did you replace the o2 sensors with OEM/OE/Genuine parts or aftermarket? Since Mercedes seem to be temperamental about anything electronic, I would stick with Genuine or OE parts. Are you in the US?
Or you could also have a bad catalytic converter.
10-30-2023, 04:28 PM
#4
MBWorld Fanatic!
Join Date: Apr 2019
Location: Silicon Valley
Posts: 5,642
Received 3,434 Likes
on
2,289 Posts
MY'14 W212 M276 3.5NA @60kMi
deciphering issues into solutions
Hi!
My car recently failed a emissions test because of too high CO. The car seems to be running rich too. I have not noticed the car running worse/rough or smell from exhaust but fuel consumption feels exsessive. The car is throwing the following DTC codes: P0170, P0137, P0172, P0138, P0136, P0141. The P0170 (Fuel Trim Bank 1) and P0172 (System Too Rich) seem to be the ones that return when cleared. It seems the bank 1 sensor 2 is just throwing codes at random and they dont immediatly return. I have changed both o2 sensors about a year ago along with the vacuum line under the air box. I checked the connection box on downstream o2 (sensor 2) and it was very oily. I checked the readings from both o2 sensors and they seemed responsive when applying throttle etc. The readings I got from o2 sensor 1 was about 1V at idle and peak at 3.157 when giving it some throttle. For sensor 2 I saw 0.35V ish at idle and peak at 1V with some throttle. I also checked the MAF which read 2.4g/s at idle and got up to 14.5 with some baby revs. I have spent some time looking for another vacuume leak but no luck. Also ordered spark plugs.
Anyone experienced the same thing or have tips or any idea what to do next?
My car recently failed a emissions test because of too high CO. The car seems to be running rich too. I have not noticed the car running worse/rough or smell from exhaust but fuel consumption feels exsessive. The car is throwing the following DTC codes: P0170, P0137, P0172, P0138, P0136, P0141. The P0170 (Fuel Trim Bank 1) and P0172 (System Too Rich) seem to be the ones that return when cleared. It seems the bank 1 sensor 2 is just throwing codes at random and they dont immediatly return. I have changed both o2 sensors about a year ago along with the vacuum line under the air box. I checked the connection box on downstream o2 (sensor 2) and it was very oily. I checked the readings from both o2 sensors and they seemed responsive when applying throttle etc. The readings I got from o2 sensor 1 was about 1V at idle and peak at 3.157 when giving it some throttle. For sensor 2 I saw 0.35V ish at idle and peak at 1V with some throttle. I also checked the MAF which read 2.4g/s at idle and got up to 14.5 with some baby revs. I have spent some time looking for another vacuume leak but no luck. Also ordered spark plugs.
Anyone experienced the same thing or have tips or any idea what to do next?
This will help us understand your issue - Volunteer friendly members can help narrow things down to a solution.
Last edited by CaliBenzDriver; 10-30-2023 at 04:31 PM.
