Stop start problems

daveyjp

Back to my first post then.  Start with the battery as its simple.  If it still isn't starting when the brake pedal is relased it points to an electrical issue and could still be the brake pedal switch.

A friend had an 8 year old Range Rover which was throwing up lots of errors with stability control, ABS etc.  He thought battery, alternator etc, but it was all down to a faulty brake pedal switch.

I had a recall on a car as there was a danger the car wouldn't start, or the stability control would fail, ABS wouldn't kick in.  The reason was the silicon in valeters cleaning fluids was affecting the brake pedal switch.  A new switch was fitted under recall.

greyteam1959

Upzeecreek said:

Plan to get the battery changed next week so will report back. 
Thanks for all the helpful tips. 

Don't just change the battery get the original battery properly tested first.
A good independent will do this free of charge.

EssexExile

It's not a battery problem, if the battery is low it won't stop in case it can't start again.

Bossyboots

EssexExile said:

It's not a battery problem, if the battery is low it won't stop in case it can't start again.

That was always my understanding.  However, my engine cut when stopped at traffic lights on a dual carriageway.  While waiting the engine briefly tried to fire and I then lost all electrics and couldn't start the car.  It was definitely a knackered battery - new one fitted, old one tested.  No doubt the old battery had had it. 

Upzeecreek

greyteam1959 said

Don't just change the battery get the original battery properly tested first.
A good independent will do this free of charge.

It's already been looked at by VW. They said the battery was weak but didn't need replacing. It just needed a good run! Well it's had plenty of good runs and it's still doing it.
VW also said they couldnt find anything else wrong with it!! 

oh_really

neilmcl said:

Upzeecreek said:

daveyjp said:

The logic to start from manual will be different from a stop/start restart.

If its like my auto for a manual start the car will be in Park and the brake pedal needs to be pressed.  Only then will it start.

A stop start will be activated when you come to a rest in Drive and keep the brake depressed.  The car restarts when the brake is released.  If your car isn't starting from this scenario it may be nothing more than a worn brake pedal switch and the signal to restart isn't being received when the brake is released.

The weird thing is ,it only seems to do it when engine is up to temperature. If it was a brake pedal switch, I would presume it would fail to restart when engine cold too.

Doesn't sound like the battery, the stop/start system wouldn't activate in the first place if the battery is undercharged nor would it come on when then engine is cold.

I run a Golf and the s/s still operates when the SoC shows 40%.

oh_really

Upzeecreek said:

greyteam1959 said

Don't just change the battery get the original battery properly tested first.
A good independent will do this free of charge.

It's already been looked at by VW. They said the battery was weak but didn't need replacing.

What's your SoC showing?

HansOndabush

Just disable the stop/start; stop/start is a bad idea anyway, the only purpose of which is to sell cars and get a lower emission figure. In practice it can be temperamental; costs you more in batteries/starters and ring gear than you ever save in fuel, and reduces engine life.

Goudy

Do you have a manual or an electronic handbrake?

If it's electronic and it's set on "auto hold" (so it holds the brakes on automatically when at a stop, in gear, without your foot on the brake) the car won't restart until you either tap the accelerator or turn the steering wheel a little.

You need to turn off the "auto hold" to get it to restart when you take your foot off the brake.

Browntoa

I've had stop start problems and random very irregular misfires on a car . Stop start would not kick in etc and on one occasion showed as it was disabled on the dash. Car never struggled to start.

Battery was tested by a specialist battery shop (not a Halfords ) and was borderline failing , it was a 10 year old battery , and so was replaced.  The wavering battery voltage was causing problems for the ECU.

Never had any problems after that