tee_tz

Thanks, hopefully that's it. I let you all know. Good to know your car is fine now.


Tee_Tz.

Midnight Koop

just noticed something... your car is a c320, right?

therefore it is not supercharged and might not have a vacuum. in that case then the solution to my rough idling may not be possible for your car.

sorry if thats the case

tee_tz

Okay, so yesterday I took the car to the dealership and they reinstalled and updated all the car's software. The result? So far, so good. Even at times when I was expecting the shaking to start it didn't happen. The car stays at idle and sounds quite, doesn't tremble or indicate that it's losing 'power'.

Today I'll drive it a little longer and further and see if the problem is completely gone or whether it comes back, but it's a first step for people having this problem. If you're covered under warranty then it's free, if not it takes 1 hour, therefore it'll be about $100 or so (depending on your dealer's labor charger per hour). I disagree with spark plugs because then your car would be shaking all the time; engine mounts - then your car would shake when your car leans left or right only (unless both sides, rare). So I think it could be software issues OR possibly wires need to be replaced/plugged in. It's difficult to completely assess because many things can lead to this same problem, but you just have to eliminate 1 by 1.

By the way, Moderators - can you merge all the other threads together -- they are a lot of questions about the same thing, perhaps it's easier if we rename it and throw everything into 1 thread for future reference.


Tee_Tz.

alexhui

My engine shakes had rough idle at stop light & hesitation from stop sign.

Problems:
Engine shakes whenever I have low RPM.
Sometimes, I try to step on gas from stop sign, and car has very little respond, or engine is about to die, but it never die.

I have automatic transmission, but it really feels like driving stick shift without enough gas pedal while I release my clutch.

What happened:
In Dec, I got a "check engine" light. I took this to 1 mechanic, and he said that engine misfired in cylinder #1.
So he replaced ignition coil pack & 2 spark plugs for cylinder #1.
The car runs fine for 1 months.

Then the problems come back again.
Everyone I spoke with (2 dealers & 3 independent mechanics) told me to wait until I see "check engine" light again.
I waited until April 6, but I still did not see another "check engine" light.
I took my car to another mechanic, and he said that engine misfired in cylinder #6.
So he replaced ignition coil & wires for cylinder #6.
So far, so good. No more hesitation or rough idle.

I am still worry about other coil & spark plugs.
I wonder is there something else which caused these coil, wires, & plugs to fail??
MAF
oxgen sensor
idle control valve
fuel line ...

But I now experience another problem starting my car immediately right after changing my coil pack.

My engine dies after 1 crank. I cannot start my engine unless I wait for 6 seconds at position#2, or hold the key at position #3.

Please help replying this post:
https://mbworld.org/forums/c-class-w203/189577-help-delay-order-start-engine.html

Thanks!!

tee_tz

Hm, did they check all the wires/plugs? Especially the ignition wires? Have them check those because there's obviously something failing to turn on the power to the engine.


Tee_Tz.

c230K415

Sorry if this is somewhat irrelevant but I noticed that on cold starts (during morning or right after school) my car will settle down to the RPM range below 1,000 but then the needle might start jumping a bit. I usually warm up my car until the RPM's settle to the lowest it will go, along with a extra two minutes or so. Lately, I have noticed that after it warms up...the RPM's needle would jump around (probably from 700-1,100 RPM's), but after about 2 minutes it would stop. I hope nothing is about to fail in my engine or even worse...a Check Engine Light (those are a stealership's dream). Can anyone give me any tips on what's going on? Thanks in advance.

p.s.
The cold start's idle is pretty rough alongside the RPM jumpung.

alexhui

Thanks for your quick reply.

They checked the wire set & ignition coils.
But I can have them recheck them tomorrow, because last time they had to replace a wire set & my #6 ignition coil.

Funny, I can still start my car.
I just have to "WAIT" 6 seconds on position #2 before turning to position #3,
or I have to keep it at position #3 for 6 seconds from the very beginning.

alexhui

[QUOTE=c230K415;2135745]Sorry if this is somewhat irrelevant but I noticed that on cold starts (during morning or right after school) my car will settle down to the RPM range below 1,000 but then the needle might start jumping a bit.

My car may idle at around 500rpm. If it jumps up to about 800-900rpm, then the shaking is gone. Also, this happens if the auxilury fan kicks in.

I usually warm up my car until the RPM's settle to the lowest it will go, along with a extra two minutes or so. Lately, I have noticed that after it warms up...the RPM's needle would jump around (probably from 700-1,100 RPM's), but after about 2 minutes it would stop.

My car will also have RPM in different ranges in the morning, and it will shift later (at higher RPM). That's how MB warms up MB cars. Hey, if it shakes at idle, then it may be a misfire. Check ignition coil pack.

RDSBENZ

I just had the dealer (Fletcher Jones) perform a Service B yesterday. This morning my car has a rough idle. Same problems you guys are having. Car shaking, rough idle, . . . but after it warms up, it's gone. After a full day at work, I started my car and there it is again but it goes away when you drive it. I got home, waited for my car to cool off. I started my car, there it is again. But this time, "check engine" light came on after giving it some gas. This happens when the engine is cold -after that, idle is fine. Before the service, my car was totally fine. I'm bringing it back to the dealer tomorrow. How much to change a coil pack and spark plug so I know what to expect from the dealer? I hope it was just a vacuum leak or something. My car is out of warranty as of yesterday. Go figure! Just my luck!!!

rdscklasse

FAMUBER

i just had this same problem last night. my car shakes/rumbles A LOT! it actually shut off on me 3 times at red lights. in order to keep the car alive, at every traffic light i would put the car in park and press on the gas and let it sit at about 3 RPM

reading the paperwork here is what it said:

Check engine light on
Found crank case vent hose leaking vacuum
Performed DTC read out found all four cylinders have a mis fire codes. Checked for vacuum leaks and found crank case vent hose leaking. removed crank case vent hose and replaced it cleared codes and test drove OK.

Midnight Koop

i wonder if all these cracked vacuums are failing at the same stress point. if so then its definitely a poorly engineered component. i wish i knew exactly where mine failed so i could reinforce that spot on my new vacuum to prevent it from happening again (out of warranty).

hope it doesn't cost you guys too much to replace.

McDub

Hey guys. I'm just another new guy with .02c. My first post, but I think I read a bazillion threads in the last couple days.

For those rough idle, possible vacuum leaks, could you possibly spray some carb cleaner near the vacuum hoses? If it sputters more...or completely dies, then you have a vacuum leak. You shouldnt need to go crazy with the can, just a few squirts.

RDSBENZ

* * *

Where do you find the crank case vent hose?

iri

Hi,

I am new to this forum, but already found it very helpful… I bought my 2004 C240 4Matic (automatic) less than a month ago with about 36K miles on the clock… The car it self looked new and had a clean history… However, about a week ago, the Check Engine light came on. I had it serviced at a garage that specializes in MBs… As you probably guessed, it was the MAS… He replaced it, reset the codes and, upon my request, changed the oil (since there is no dip-stick and it was hard to tell what state the old oil was in). Since then, the car idles a little rough/shakes a little and hesitates when taking off from stop. Since yesterday, though, it stated dying on me when I first come to a stop --say on a traffic light. Restarting after that is no problem and the car will stay on (idling smoothly) even if I am still stopped. The problem seems to be more pronounced when the car is cold, but could still happen after a 10 minute drive in the morning or on my way home at the end of the day. I live on the east coast, so the temp here is fairly mild in May (mid 70s to mid 80s during the day.) The problem is a little worse if the AC is on (but I don’t think there is a direct relation there.)

To be fair, I noticed a bit of the rough idling/hesitation before the Check Engine light came on/car was serviced.

I have read this and another related thread, but they both seem to end abruptly. Has anyone come-up with a “definitive” cause or additional recommendation for this issue?

Any feedback is much appreciated, especially that my car is not under warranty and all repairs come out of my pocket! Thanks.