Engine rough when first started. M273
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Senior Member
Joined: Aug 2005
Posts: 408
Likes: 105
Engine rough when first started. M273
Howdy and happy holidays to you all.
It’s been going on for a while but I notice now that it’s cold, when I fist start the car the engine is a bit rough, angry feeling and you can feel it through the steering wheel. I feel slight vibrations at 2k rpm but within a minute or so it will smooth out. Basically the first 0-30 seconds or less. It’s close to feeling like when the engine balancer (crank pulley) is wobbly. I don’t think M273 has a balancer and the crank pulley looked fine, although I should take a look again.
128k miles on car. 4 magic. 2008 s550
20k miles on MB engine mounts, trans mount and spark plugs.
I was wondering if the ignition coils are tired, but there are no codes. Last year one did giving me issues and I changed one after it showed a code. Is there a way to tell if coil is bad even if it doesn’t throw a code?
This issue could also lead to solving my other long time problem of slight vibration at 50-70mph under load, which we discussed could be the center support bearing/bushing, which I will have checked out soon. But I’m hoping it’s the engine that’s sending the wiggles.
Thoughts?
It’s been going on for a while but I notice now that it’s cold, when I fist start the car the engine is a bit rough, angry feeling and you can feel it through the steering wheel. I feel slight vibrations at 2k rpm but within a minute or so it will smooth out. Basically the first 0-30 seconds or less. It’s close to feeling like when the engine balancer (crank pulley) is wobbly. I don’t think M273 has a balancer and the crank pulley looked fine, although I should take a look again.
128k miles on car. 4 magic. 2008 s550
20k miles on MB engine mounts, trans mount and spark plugs.
I was wondering if the ignition coils are tired, but there are no codes. Last year one did giving me issues and I changed one after it showed a code. Is there a way to tell if coil is bad even if it doesn’t throw a code?
This issue could also lead to solving my other long time problem of slight vibration at 50-70mph under load, which we discussed could be the center support bearing/bushing, which I will have checked out soon. But I’m hoping it’s the engine that’s sending the wiggles.
Thoughts?
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I've overseas driving a Toyota Hilux pick up truck - the centre bearing was gone (nothing left of the pathetic rubber mess that fails on Mercs as well) there is no way your engine is the propshaft failure vibration - but the new cold start thing sounds like a misfire - is this driving or stationary - if you are driving or in D, then likely the torque converter clutch is toast (they fail mostly leaving drive all the time),
Thread Starter
Senior Member
Joined: Aug 2005
Posts: 408
Likes: 105
I've overseas driving a Toyota Hilux pick up truck - the centre bearing was gone (nothing left of the pathetic rubber mess that fails on Mercs as well) there is no way your engine is the propshaft failure vibration - but the new cold start thing sounds like a misfire - is this driving or stationary - if you are driving or in D, then likely the torque converter clutch is toast (they fail mostly leaving drive all the time),
The roughness is in Park when first starting the car. It’s most noticeable when very cold, goes away within 30 seconds. Car is very smooth 75-100 mph.
Prop shaft failure is not a suspect, I checked the vin of the motor before buying the car.
Thread Starter
Senior Member
Joined: Aug 2005
Posts: 408
Likes: 105
MBWorld Fanatic!
Joined: Aug 2014
Posts: 5,337
Likes: 1,683
S500
