rough idle

c220ghost
15

Asked by c220ghost Sep 30, 2011 at 06:15 PM about the 1994 Mercedes-Benz C-Class 4 Dr C220 Sedan

Question type: Maintenance & Repair

when i am driving it runs perfect but when it is stopped or put it park it runs rough?

22 Answers

ibrahim_9090
85

I had the same prblm, the solution for me was funny, i just put some oil on the ignition parts under the hood. It was just stucking from dust or rust. try that, it could help :)

6 out of 6 people think this is helpful.
c220ghost
15

i give that a shot this weekend, Thanks.

Sudhan Swamy
125

its the same problem in my 2002 c200,it caused by the nuetral pooly and the engine fountdation.......

11 out of 11 people think this is helpful.
c220ghost
15

Is that an easy fix?,

Sudhan Swamy
125

you have to put arround 12-15 grands for the fix and have to order parts from company.

1 out of 1 people think this is helpful.
Lorne Grandison
1,495

Rough idling can be cause by a couple of things, vacuum leak somewhere in the intake, a dirty throttle body. ( it has passage ways that allow for idle when the throttle is closed, if those passage ways are dirty it can affect the idle, car might idle too low and even stalls) or it could be just the engine mounts are bad and you are mistaking the extra vibration as a rough idle. I would rule out spark plug or spark plug wires only because the rough running would continue when you are driving or possibly gets worst with additional engine load.

6 out of 6 people think this is helpful.
Lorne Grandison
1,495

I would not suggest putting oil on your ignition parts

2 out of 2 people think this is helpful.
ibrahim_9090
85

Yes, Lorne, I really apologize for the website and all readers. I used the word "ignition" instead of "injection" but I said " under the hood" to make it more clear. My english is not very good :( sorry for that, but waht I put oil on is these parts in the picture and the things around (i.e. when you press on the penzine pedal it should come back, but in my case it wasn't), and it really worked for me because there was a lot of dust and rust on them that caused hard moving for the cord. Thank you for correcting my mistake.

2 out of 2 people think this is helpful.
c220ghost
15

i worked on it over the weekend and i found that the trottle body boot would not get tight and like you said everytime i gave it a little gas i could here a vacum leak. i will start by getting a new boot for the trottle body and i will see if that gets me to pass emissons, you see the problem that i have is that when you turn it up on the test it is dumping to much fuel up top and even though it runs ruff at idle it runs very clean and passed that part of the emissons test. you see thats whats crazey because when you turn it up it runs smooth, go figure!!

1 out of 1 people think this is helpful.
Lorne Grandison
1,495

Hmmm, so what you're saying is it idles ruff but passed that part of the test and runs smooth off-idle but fails that part because it's running too rich ( too much fuel). If you had a vacuum leak at the throttle body you'll be running lean not rich as you are now. You see with a vacuum leak, unmetered air is getting into the engine without passing through the air mass sensor, therefore the computer can't account for that unmetered air and can't calculate the correct fuel trim hence more air than fuel and the car runs lean. You said you car is running rich ( more fuel than air) so we have to look for things that would make a car run rich. Check for these things 1. Is your car fully warmed up when you take the emissions test? It has to be at normal operational temp. By design most cars are programed to run rich when cold to get the catalytic converter up to proper temp faster 2. Is your oxygen sensor working properly? ( Check your OBDII fault code at pep boys, It might not be enough to turn on the engine check light but might still register a pending fault code) The engine computer uses this sensor to check how much O2 is in the exhaust and adjust the fuel accordingly. if the sensor is bad the computer miscalculates and most likely will inject more fuel than needed ( car runs rich) 3. Dirty injectors ( irregular spray pattern, fuel comes out in a stream instead of a fine atomized spray) that will sure to make the car run ruff and run rich 4. Worn spark plugs or plug wires, but in the absence of hesitation and misfiring under load which you never mentioned as a symptom we can almost rule that out, besides, modern spark plugs are good for 100K miles these days.

5 out of 5 people think this is helpful.
vishv1
70

Idling problen on merc 230E.Can anyone help

7 out of 7 people think this is helpful.
aepling
10

I have an '82 SEC that had idle problems for a year and finally got unbearable. I finally found out that the problem was that corrosion had eaten holes in my intake manifold and it was leaking air. This upset the vacuum lines that depend on a vacuum to maintain a steady idle. Check for vacuum leaks with a smoke generator injecting smoke into any vacuum line and see where the smoke comes out. That's a leak that needs to be plugged. Other than that, there is the Idle Control Unit computer and the Idle Control Adjustment Valve, all which control the idle. I replaced both before I found out it was a simple vacuum leak.

teslapc
10

I had the same problem. I changed the spark plugs and the problem was gone.

1 out of 1 people think this is helpful.
mercedesconeeighty
15

i have a 02 mercedes c180 6 speed gear box 2ltr petrol saloon i have it a week and in the morning when you start the car it will start with the first turn but engine loses power for 30-40 seconds and noise coming from under the bonnet but i dont think its the engine but when i drive car its like its driving perfect but today i came back from around 30mile journey and car was started and just started losing power and when i tried to accelerate there was nothin and car just cut out..every time i try to start it it will start and lose power then cut out in the space of a few seconds.. please i need help any answers would be helpful..thanks

1 out of 1 people think this is helpful.
98C230Kdriver
10

Look for air leaks in the vacuum lines or in the air intake. Few points need to check: the fuel you have used might have been NOT a premium or 91, the spark plugs/ cables are wearing out.

1 out of 1 people think this is helpful.
98C230Kdriver
10

If you have changed your belt you need to make sure to use the TDC procedure when putting on the new one.

JeanieJinglesH
0

Hi everyone - I am driving a Mercedes C180 2004 model, at first it only occasionally started misfiring when low revs or stopped at a stop street. The idling sounded very erratic as well. It only got worse during the past year. One Mercedes specialist told be that my cars engine is a gonner and the timing chain and gears were also damaged. Another one told us that our ECU was faulty and then suddenly there was no pressure on the one valve and so the so-called list of difference diagnosis started. It turned out to be the catalytic convertor which was missing and causing all the problems. The previous owner had it removed when replacing the x haust. I found a magnaflow catalytic convertor which also works on the Merc and much cheaper than the Mercedes original. My car is 100% better.

sujays86
10

rough idle in low speeds is usually due to leaking of vacuum lines check and replace the connectors / tubes ( see pic of vacuum line connector of C 180 petrol )

1 out of 1 people think this is helpful.
aepling
10

Mine had holes in the manifold that had to be filled in with JB Weld or something similar. Run smoke into an outlet and see where it comes out. That's the leak.

1loyd
40

For rough idle problem check the fuel pressure regulator (on injection system @ front top of motor) it has a small rubber vacuum line on it, with the engine running; gently pull off the vacuum hose and hold it about 1/4 inch away from nipple. If you see petrol coming from the nipple on the regulator into the vacuum hose - there's your problem! Replace the fuel pressure regulator and it will run like new!

1 out of 1 people think this is helpful.
dps42
30

I have a 2009 c300. My check engine light came on right after I changed the air filters. I have a rough idle, but runs fine on the road. Mass air flow sensor? 02 sensor?

3 out of 3 people think this is helpful.
HerbertHerbo
5

i have a MB c 180 1996 manual transmision, previously would stall will in gear and while driving, was diagnosed and mmixture was found too rich and idle control in emergecny, the mechanic advised me to replace harness and oxygen sensor first but i feared touching harness, i dealt with oxygen sensor first, it ran well for about one month, after fueling it just started misfirng and stalled, am thinking the harness is messed up, help plez Herbert in kampala,

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