Simba Mlambo

Good day all I am new here, just joined this platform Hoping that my problem might be solved.i have a 2001 Mercedes c180 m111 engine.i bought the car used also with some problems. The car have idling issues,I goes up and down on idling (the idling is not constant.i first did the top complete,change mas airflow sensor, change oxygen sensor as per diagnostic instructions,change throttle body, checking vacuum leaks but I am not winning.the car drives perfect when I m exerating also when it's in gear its idling fine,my only challenge is when in neutral(idling).help please,thank you

speedlimit

Hi!

Welcome to MBworld!

Thank you for checking in, good luck with your car! Let's try the W203 forum for help from fellow owners.

Bob

AlexGeorgiev

Firsti sorry for my English not main language!

Sounds like a vacuum hose for me. I've got the same problem moths ago but with the newer engine M271 (c200). I'm with manual transmission but I don't think is different with the automatic. I had the same idling issue when my car is on neutral going up and down but if I go with gears was totally fine. Changed MAF,Sparks,Coils,Acc Pedal and some other things with no luck xD. And one morning | decided to take a better look on the engine hoses, for my surprise I found one broken hose " CRANKCASE GAS HOSE", I translated it from my language so probably this is not the real name of it. And man after I fix it the problems with idling stoped immediately so I think is the same with you but who knows. I added you some photos but remember its not the M111 Engine it is M271.

Simba Mlambo

Thanks Mr Alex for your reply ,I have m111 c180 manual.the issue of vacuum leaks I tried to check with no luck.the other part that the machine detected is cam position sensor, might it be the cause?, also I had some saying it might be bent valve but the car when I press gas pedal it runs smoothly, will bent valve be possible?,the other issue my idling is misfiring, please help, thank you

AlexGeorgiev

Hello Simba, |'m not mechanic so don't know if its right to trust me xD, I just wanted to tell you that I had the same symptoms with my car and it was a vacuum hose... I get the same as you misfire on cylinders because of mine broken hose.. But I don't think that "cam position sensor" can do somthn with the idle or if it does will go no matter if you are on gear or neutral.. Тhe cam sensor will throw misfire too but again don't think it is it. Still thinking its vacuum hose. Mostly check them around the MAF and throttle body.

cgshawaii

On computer-controlled cars with onboard diagnostics, the VERY FIRST THING to do is to scan the engine computer for malfunction codes. I don't know the situation in your country so I couldn't guess whether this would reveal the truth about a cam position sensor.

Georgiev above has posted excellent advice to ensure that all engine vacuum hoses are in good condition. They frequently deteriorate at their ends where they are connected to something, then develop a crack which defeats the purpose of the device connected to.

I don't think from the sparse information provided, that it is a bent valve.