I have a new 2016 C300 4 matic. I've read through every thread regarding questions about the eco start/stop. Some people like it, although many hate it. I decided to try one tank with it on and another with it off to see if it really makes a difference with my mpg with city driving (no bumper to bumper traffic).

Today I drove about 20 minutes and noticed that some times when the engine shut off at a light, it made a very deliberate noisy start (like when you start the car with the button) Other times, such as a stop sign, the start up was not noticeable at all.

Is the re start affected by how I apply the breaks?

Does the car have a problem or is it me?

I must admit, I'm looking forward to turning it off next tank of gas. (I can't believe for my type of driving it's going to make much of a difference because I only drive 200 miles per month!)

 

moved to W205 forum...

 

FYI. I did the same thing between 2 tanks of gas. The difference in MPG was very noticable @ 3mpg. I was very surprised.

 

MPG difference depends on how often you stop and how long you stop for. If you are driving on a highway with 1 or 2 stops at less than 10 seconds a stop then I can see it doing hardly anything. If you are in a city with many stoplights at 30-60 seconds a pop 15 times during a commute or in traffic for 10 minutes with no one moving an inch I can see a major difference.

As far as the sound, maybe you just notice it more because at a stop light you are stopped for a longer period of time.

 

I've had my 2016 C300 4Matic for 2.5 weeks and I have a love/hate relationship with the eco start/stop. This "feature" is not foreign to me, owing to several similarly equipped loaners over recent years, but it's really odd for the engine to be completely silent when stopped.

I've left eco start/stop on because it clearly results in better gas mileage than turning it off, and I drive almost exclusively in city stop-and-go traffic. That said, like yours, the start engine thump is more noticeable at certain times. It does seem that the feature is activated with modest pressure on the brake, but the instrument cluster notification isn't illuminated unless the brake is pressed down hard.

What I don't like is that in stop-and-go traffic, the stop/start barely re-engages before it activates again.

 

Can anyone comment on combining the HOLD feature (double tap brake pedal) with the start/stop? It should work in theory right?

My main issue with start/stop and its only been recently is how sensitive it's become. It seems that if i just ever so slightly relax my foot but the car is still braked and locked into place the engine turns on and assumes im ready to go.

 

It works fine with the Hold feature. The only difference is the engine restarts when you hit the gas pedal instead of when you take your foot of the brake.

 

The other thing that I've noticed is that the restart is much rougher if the brakes are applied when it happens. When it's very hot outside, it'll often restart the engine because of the A/C (even if set to "eco" mode), and when that happens — especially with brake hold — it shakes the car much more noticeably than when restarting because I've taken my foot off the brake or hit the accelerator

 

I'm surprised but happy to hear people reporting a (sometimes) significant mileage improvement with start/stop engaged. But don't forget that when the engine is off, it's also NOT blowing exhaust fumes into the air. Its my understanding that part of the motivation for this feature is exhaust emission reduction (in addition to mileage improvement).

 

Same here in mine. I get quite a shake when the eco start is restarting the car at a complete stop due to the AC or other battery reason, it's quite embarrassing since I can see my own body shaking. However, it's a lot smoother if the start is triggered by me taking my foot of the brake and start acceleration.