vibration at idle

[frog1520]

I've noticed a vibration at idle on my W140. The steering wheel to a greater extent, and the whole car to a lesser extent vibrates when the car is stopped but in D. The revs are just over 500.

Shifting to N or P stops the vibration, and the revs go up a few hundred.

Holding it on the brake and giving it some gas to move the rev counter up also stops the vibration.

So it seems to be vibrating because the engine is at 500 revs...

Any ideas?

Thanks!

 

[Brian WH]

I've noticed a vibration at idle on my W140. The steering wheel to a greater extent, and the whole car to a lesser extent vibrates when the car is stopped but in D. The revs are just over 500.

Shifting to N or P stops the vibration, and the revs go up a few hundred.

Holding it on the brake and giving it some gas to move the rev counter up also stops the vibration.

So it seems to be vibrating because the engine is at 500 revs...

Any ideas?

Thanks!

The cars revs will drop slightly when put into drive. 500 seems a little low though and may be the cause of the imbalance under load, causing the vibration.

Has it always dropped to 500 or is this new?

 

[frog1520]

The cars revs will drop slightly when put into drive. 500 seems a little low though and may be the cause of the imbalance under load, causing the vibration.

Has it always dropped to 500 or is this new?

To be honest mate, I'm not sure!! But I've only noticed the vibration in the last month or so...

Is the idle rev rate something you can still adjust, or is it all ECU these days?

Thanks!!!

 

[Stratman]

Is it because of the arrival of the hot weather and hence the aircon?

My C180 does just that. A/C off and only the tach indicates that the engine is running, A/C on and there is a little roughness at idle as the compressor puts extra load on the engine.

 

[frog1520]

Is it because of the arrival of the hot weather and hence the aircon?

My C180 does just that. A/C off and only the tach indicates that the engine is running, A/C on and there is a little roughness at idle as the compressor puts extra load on the engine.

Interesting!

I always have the A/C on anyway, but I'll try and turn it off and see if that makes any difference! Thanks for the info!