C180 kompressor idle issue
Thread Starter
Newbie
Joined: May 2022
Posts: 8
Likes: 0
2006 Mercedes-Benz C180 Kompressor
C180 kompressor idle issue
Im having this strange issue since replacing the $12 hoses (wasnt a problem but thought of doing it anyway as i was changing serpentine belt). Car feels like it doesnt have much boost, also sometimes when coming to a stop the rpm stays at 1200rpm until i either pull away and change gears or by its own but completely random. It idles at about 900rpm which I think might be higher than it did before work was done. I have tested for vacuum leak with smoke and all i can see is at the intake manifold there is a small nipple under what seems to be a temp sensor that goes into a bigger hole above it. When plugging that nipple on idle the cars STFT goes to -24% but leaving it as it was (open) its about 6%. So the question would be what could be causing no or little boost and weird stuck 1200rpm sometimes. Also is the pre cat o2 sensor a wideband sensor? As the post cat according to by obd2 scanner hovers 465mv - 750mv while the pre cat sensor hovers at 1500mv and has jumped regularly to 3000-5000mv. I cleaned the MAF sensor when i did the job with maf sensor spray by liqui molly and also that temp sensor in the intake manifold. The MAF seems fine according to my multimeter. Im at wits end cant really seem to diagnose the issue and there are no stored codes.
Last edited by WurminatorZA; May 6, 2022 at 11:15 AM.
Thread Starter
Newbie
Joined: May 2022
Posts: 8
Likes: 0
2006 Mercedes-Benz C180 Kompressor
It seems like theres an overfill small pipe by the windscreen wiper fluid tank that might go there on that nipple, what would be the point of that?
Nevermind it doesnt go into the wiper fluid tank it goes around it somewhere, that fixed the issue. Wonder what it is.
My car is reading -25% at idle on the STFT but not tripping any rich codes, LTFT at 4.6%. When driving STFT goes to more normal ranges, the car drives fine and has boost again after connected the small pipe, but what can cause rich STFT in idle? I'm still worried about 02 sensor 1 bank 1 which is pre cat giving readings of 1500mv at idle and jumping to 5000mv in some instances when driving.
MAF sensor reading 3.5g/s at idle is also seeming a bit high for a 1.8l engine unless it might be a bit wind but doubtful.
After checking values again today at idle STFT at -17% so went a bit down and the LTFT stays at 4.6% and am starting to worry why its not changing. Also noticed when turning the steering wheel in idle the STFT goes down to -7%. Im pretty much just relaying all things ive noticed so far.
Nevermind it doesnt go into the wiper fluid tank it goes around it somewhere, that fixed the issue. Wonder what it is.
My car is reading -25% at idle on the STFT but not tripping any rich codes, LTFT at 4.6%. When driving STFT goes to more normal ranges, the car drives fine and has boost again after connected the small pipe, but what can cause rich STFT in idle? I'm still worried about 02 sensor 1 bank 1 which is pre cat giving readings of 1500mv at idle and jumping to 5000mv in some instances when driving.
MAF sensor reading 3.5g/s at idle is also seeming a bit high for a 1.8l engine unless it might be a bit wind but doubtful.
After checking values again today at idle STFT at -17% so went a bit down and the LTFT stays at 4.6% and am starting to worry why its not changing. Also noticed when turning the steering wheel in idle the STFT goes down to -7%. Im pretty much just relaying all things ive noticed so far.
Last edited by WurminatorZA; May 7, 2022 at 04:31 AM.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 3,275
Likes: 236
From: BC, Canada
2003 C230K Coupe Orion Blue
Just curious, do you know which engine model you have? In North America the C230 is a non supercharged V6 (M272) for 2006. For 2006-2007 the engine selection deviated quite a bit from the earlier years. Sounds like you have the M271 I4 engine but just want to verify.
Any CEL? If so, it would be prudent to post any codes here as well.
Not sure about the particular O2 sensor specifications for your car but my (rather poor) understanding is that they typically run in the 0-1V range. Unless there's something I don't know about for this car model, 5V sounds high.
Any CEL? If so, it would be prudent to post any codes here as well.
Not sure about the particular O2 sensor specifications for your car but my (rather poor) understanding is that they typically run in the 0-1V range. Unless there's something I don't know about for this car model, 5V sounds high.
Last edited by slammer111; May 7, 2022 at 11:45 AM.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 3,275
Likes: 236
From: BC, Canada
2003 C230K Coupe Orion Blue
Thanks for posting the graphs. Learned something new. 
Also that would eliminate the O2 sensors as the culprit.
OP, did anyone (yourself or another mechanic) work on the intake side of the engine before these problems appeared? Did this problem simply appear one day? Any additional information here would be helpful. Also do you have a photo of the (nipple) sensor in the original post?
I assume there are no leaks in the intake system leading up to the throttle body. The hose between the silencer (in front of the serpentine belt) and the EGR is known to crack, though it probably won't result in a huge loss in intake pressure.
Also that would eliminate the O2 sensors as the culprit.OP, did anyone (yourself or another mechanic) work on the intake side of the engine before these problems appeared? Did this problem simply appear one day? Any additional information here would be helpful. Also do you have a photo of the (nipple) sensor in the original post?
I assume there are no leaks in the intake system leading up to the throttle body. The hose between the silencer (in front of the serpentine belt) and the EGR is known to crack, though it probably won't result in a huge loss in intake pressure.
Last edited by slammer111; May 7, 2022 at 11:58 AM.
Thread Starter
Newbie
Joined: May 2022
Posts: 8
Likes: 0
2006 Mercedes-Benz C180 Kompressor
Thanks for posting the graphs. Learned something new. Also that would eliminate the O2 sensors as the culprit.
OP, did anyone (yourself or another mechanic) work on the intake side of the engine before these problems appeared? Did this problem simply appear one day? Any additional information here would be helpful. Also do you have a photo of the (nipple) sensor in the original post?
I assume there are no leaks in the intake system leading up to the throttle body. The hose between the silencer (in front of the serpentine belt) and the EGR is known to crack, though it probably won't result in a huge loss in intake pressure.
Also that would eliminate the O2 sensors as the culprit.OP, did anyone (yourself or another mechanic) work on the intake side of the engine before these problems appeared? Did this problem simply appear one day? Any additional information here would be helpful. Also do you have a photo of the (nipple) sensor in the original post?
I assume there are no leaks in the intake system leading up to the throttle body. The hose between the silencer (in front of the serpentine belt) and the EGR is known to crack, though it probably won't result in a huge loss in intake pressure.
MBWorld Fanatic!
Joined: Dec 2003
Posts: 3,275
Likes: 236
From: BC, Canada
2003 C230K Coupe Orion Blue
I remember having some weird trim numbers (weird enough to trigger a CEL) once. Did you check all the vacuum lines at the top of the engine?
Trending Topics
Thread Starter
Newbie
Joined: May 2022
Posts: 8
Likes: 0
2006 Mercedes-Benz C180 Kompressor
I remember having some weird trim numbers (weird enough to trigger a CEL) once. Did you check all the vacuum lines at the top of the engine?
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
Newbie
Joined: May 2022
Posts: 8
Likes: 0
2006 Mercedes-Benz C180 Kompressor
No luck, car is not running bad and and the MPG is about 7.9L/100KM when driving long normally, in town its about 9.4L/100KM. Engine only 90000KM on. STFT seems very normal when driving and it did go from -17% to -14% with new spark plugs at idle, also spark plugs are healthy tan brown no Rich or Lean signs. It might be normal at idle but who knows. I did add Liqui Molly Injector Cleaner to tank after the service so that might have an effect will have to see when I refill again. The LTFT on Bank1 stays the same though with no change at all.
