981 Boxster Stop-Start system

[elliotw]

I have a 981 Boxster. I drive with the stop-start system activated.

I find 9 times out of 10, when I come to a stop the stop-start does not cut out the engine and instead I have the symbol on the dashboard - the A in a circle with a line through it - showing that the engine is still running (and the needle on the rev counter is still showing some engine activity). I am not sure why the stop-start does not cut out the engine in these circumstances. I thought this may have something to do with the power drain of, say, the AC, but it doesn't seem to matter how much power I am drawing from the car. It basically makes the stop-start system totally ineffective as it almost never comes on.
Any thoughts as to why or how I can fix this?
Thanks

 

[Norris997]

Hi I am a mechanic and have seen a fair few Start/Stop problems on numerous makes and models.
most systems need a tight tolerance on how much charge is in the battery, usually about 75 % charge is needed.
also they wont stop if the engine temp is cold or as you mentioned have power draw such as air con or heated seats.
Does your car do short trips or motorway miles? I've seen it when cars are only doing short ish trips the battery doesn't get fully charged about the threshold.
The first thing I would try is charge the battery to 100% then test it, if still no joy it might have a fault in the ecu that is stopping this working
hope this helps
Dave

 

[elliotw]

Thanks. Yeah - normally short-ish journeys, say less than 30mins or so. That could be why...

 

[Norris997]

could be it, I'd try charging it fully and going for a good blast for a while.
even if it doesn't work you'll come back with a smile

 

[Red981]

It won't work if you have sport or sport plus selected : - )

 

[elstonc]

Don't worry, mine's just the same. I came to the same conclusions as norris2208. Even at the end of a long run it doesn't work if I've got / had fan, headlights, wipers running - which is typical at the moment. Even if you think your battery is fully charged, it's surprising how long a trickle charger will keep putting yet more charge into it.

 

[majorporsche]

My recent Cayenne diesel purchase is my first experience of Start/Stop, I'm wonder what the long term prognosis for battery life is, do the batteries have a much shorter life ?