Auto Start Stop

[Cybermenace]

Right I think I have came across a problem,
My auto start stop only kicks in sometimes,
it's left on and in my previous cars it stays off until I have hit the clutch but with my mini when it does kill the engine which is very rarely it's staying off for maybe 15 second then starts the engine again,

Any help would be great,
Billy

[Eddie_JCW]

Hi Billy, It could be a few things but my money is on the A/C being switched on ;)

[Craig]

Wot Eddie says. Plus colder temps cause it to come back on quicker than it should and also if you have heated screens on too sometimes it won't even shutoff...


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[Angib]

Most of the reasons like internal/external temperature or state of battery charge will also prevent the stop/start from stopping in the first place.

One thing I read that fits the 15 second pattern would be a loss of brake servo vacuum from someone who had a servo leak.

This time of year, the stop/start does change - I now drive two or three junctions further before it begins working, compared to summer.

[Gismo]

Call me old fashioned, but, to continually stop start a car is a recipe for disaster and early failure for the starter motor :Whistle:

[Eddie_JCW]

Call me old fashioned, but, to continually stop start a car is a recipe for disaster and early failure for the starter motor :Whistle:

You are old fashioned :p thankfully it's an uprated starter and battery ;)

[Mon the fish]

Call me old fashioned, but, to continually stop start a car is a recipe for disaster and early failure for the starter motor :Whistle:

I'm with you. When we had the Clubby, the first thing I did was turn the damn thing off. IMO it's only fitted to get good CO2 figures, can't see it saving a huge amount of fuel in the real world

[Rob Gavin]

I'm with you. When we had the Clubby, the first thing I did was turn the damn thing off. IMO it's only fitted to get good CO2 figures, can't see it saving a huge amount of fuel in the real world

I thought the same as you guys however a friend of mine has a mazda 6 with a timer on the start stop function and has recorded pretty much 1.5 hours stopped for every 1000 miles. Obviously depends on your driving, commute etc but it certainly surprised me

[mini mad andy]

The main concern I have is if you have been doing a bit of hooning about and you have to stop quickly, when the engine stops the oil feed to the turbo stops while it is still extremely hot and spinning fast. This is why if the engine is hot I let the car idle for a while before switching it off.

This will be more of a problem with petrol engines as their exhausts get hotter than diesels.

[Mon the fish]

^^ The oil in the bearings carbonises, and bye-bye turbo

[Eddie_JCW]

Again they've thought of that too and there's an electric water pump that stays on after shut down to dissipate the heat from the turbo :)

[Eddie_JCW]

Having said that I tend to drive off boost for a few miles if I know I'm going to be switching it off

[emicen]

I thought the same as you guys however a friend of mine has a mazda 6 with a timer on the start stop function and has recorded pretty much 1.5 hours stopped for every 1000 miles. Obviously depends on your driving, commute etc but it certainly surprised me

Typical figures for fuel consumption at idle are between 1/2 and 1/3 of a litre per ten minutes. Worst (best?) case, that's a gallon per each 1.5 hours mentioned above.

At a nominal 45mpg, saving a gallon of idling fuel would pull that up to just over 47mpg. That's not bad, nearly 5% improvement.

The simple solution to stopping it killing the turbo would be just keeping the clutch dipped when you've been hooning and have to stop...?

[Mon the fish]

That's pretty impressive when you think about it, an idling engine only uses 2/3rds of a gallon per hour. Not bad at all

[mini mad andy]

Again they've thought of that too and there's an electric water pump that stays on after shut down to dissipate the heat from the turbo :)

Yes that will help cool the turbo down but the damage would be done by it spinning with no fresh oil being supplied to the bearings as the coolent does it job.