I have read a number of threads on the merits or otherwise of the stop/ start system on the yeti.

from what I understand it would appear that the starter motor is used to restart the engine, although there does seem to be some schools of thought that this is not the case?

I leave mine in the activated position as environmentally at least it is less polluting in built up areas. 
I do think that ’selecting park if stopped for a longer time so that you can take your foot off the brake pedal to stop the brake lights showing all the time you are stationary is a good idea.

Does anyone have any info to the contrary? 

How else would it restart if not by using the starter motor? 🤔  The potential issues are increased starter motor wear and shorter battery life.  

Stopped for a while in traffic and into N with the Parking Brake applied does the job without going through reverse and flashing the reversing light and then into P and having the front wheels locked as well, 

then back through R & N to D. 

Further reading if you need to learn the background details, they mention beefed up components.

I certainly never had any trouble with many miles of stop/start journeys.

https://procarmanuals.com/pdf-online-vag-ssp-426-start-stop-system-2009/

Stop start cars are fitted with a larger capacity battery and stronger starter motor to make up for more use.

I often see comments suggesting that using auto stop-start doesn't save much fuel. I normally leave mine activated because I think it's the right thing to do, and I've always thought it does make an average 3-5 MPG improvement. - accepting that the fuel computer can be a little 'optimistic' , I ran a little test on my normal run to work at 0-dark hundred this morning. Stop-Start was unavailable due to several factors, engine was pretty much up to full temperature, oil temp. was around 55deg. and I could see the average consumption figure decrement by 0.1 MPG for every 5-6 seconds stopped at lights - so about 1 MPG for every minute idling.   

Better for the environment? No.

how about catalysts which cool down during stop and have to come up to temperature, same aplies to dpf’s. Bad for the dpf/catalyst, bad for the environment because they only work optimal on operating temp, everything lower than that is no good for both.

Best is to let the car run, except when you have to wait a long time.

Welcome to the forum.

Cats can retain operating temperature for at least 10-15 minutes (some sources quote up to 25 mins) Idling engine will not usually generate sufficient heat to get cat to correct operating temp. Better all round to stop idle, certainly if stopped for more than 10-15 secs.

Edited 7 February, 20233 yr by Warrior193
Add welcome

No need to welcome, I just don’t post that much👍🏻.

it might be true that they retain their heat, but most people use s/s in cities, but the s/s was never intended to be good for the environment, it is intended for higher mpg which in turn would be be green. It is not green for your engine.

Hi Bas, I'd have to disagree that the S/S is not intended, at least in part, to help the environment - an idling engine is producing zero MPG, going nowhere, but still producing exhaust emissions. 

On 29/01/2023 at 20:07, toot said:

Stopped for a while in traffic and into N with the Parking Brake applied does the job

 

The engine will restart if you take your foot off the brake in N, even with the handbrake applied.  Never have understood why, though: you can't move the selector out of N without putting you foot back on the brake so there's no real safety element to it that I can see.  OK, so a weak/badly adjusted handbrake could mean that the car could start to roll away on a hill, but the driver should be aware of what's going on - shouldn't they?  As it is, the courtesy of using only the handbrake when stationary in traffic requires the extra step of moving the selector to P to avoid the engine restarting - at which point the handbrake becomes redundant anyway.  It's almost as if the stop/start logic doesn't take the handbrake in to account at all.

 

I'm told that plenty of other cars will happily sit in N with the stop/start active and just the handbrake on.

On 29/01/2023 at 19:49, Schtum said:

How else would it restart if not by using the starter motor? 🤔  The potential issues are increased starter motor wear and shorter battery life.  

AFAIK, there is a single exception to using a starter motor for S/S - The Mazda I-Stop - this uses timed injection and ignition to the cylinder nearest (after) TDC on compression stroke to get engine rotating from auto stop.

Edited 8 February, 20233 yr by Warrior193
correction

6 hours ago, Warrior193 said:

AFAIK, there is a single exception to using a starter motor for S/S - The Mazda I-Stop - this uses timed injection and ignition to the cylinder nearest (after) TDC on compression stroke to get engine rotating from auto stop.

 

Hybrids tend to use the motor generator to restart rather than the starter motor.  Certainly my Swift only uses the starter motor for the first start on each drive cycle.  Every subsequent one uses the hybrid motor.