Stop Start on 981 has a mind of its own
Discussion
Does anyone know the parameters or algorithms that stop start uses, as its operation seems totally sporadic.
In every car I have driven (beside Porsches) the stop start its operation is consistent and the engine can be stopped for minutes at a time.
Sometimes it works in my Cayman but sometimes it doesn't, I know its influenced by battery voltage, ambient temperature and electrical load but I can't seem to figure out a pattern for it working.
For example; driving at 70mph for an hour then coming off the motorway and stopping at a red light, it won't work. Strange as you would think the battery would be fully charged.
On the contrary, start the car and turn the A/C off, drive up to the gate to exit the work car park and despite the cold engine the engine stops while I wait for the barrier.
Also when it does work sometimes its only for 5 seconds and sometimes longer, the longest its ever worked is 60 seconds.
In every car I have driven (beside Porsches) the stop start its operation is consistent and the engine can be stopped for minutes at a time.
Sometimes it works in my Cayman but sometimes it doesn't, I know its influenced by battery voltage, ambient temperature and electrical load but I can't seem to figure out a pattern for it working.
For example; driving at 70mph for an hour then coming off the motorway and stopping at a red light, it won't work. Strange as you would think the battery would be fully charged.
On the contrary, start the car and turn the A/C off, drive up to the gate to exit the work car park and despite the cold engine the engine stops while I wait for the barrier.
Also when it does work sometimes its only for 5 seconds and sometimes longer, the longest its ever worked is 60 seconds.
Bennachie said:
First thing I do after starting the car is........ turn it off.
Wish we had the US of A option for it to remember what mode it was last in. Reverting to 'on' is a pain.....
On the likes of the motorway I don't mind it, but yes in a busy town with roundabouts etc. the car stays in sport mode.Wish we had the US of A option for it to remember what mode it was last in. Reverting to 'on' is a pain.....
I had a diesel Panamera for a week which I did a few hundred miles in and I couldn't get that to work full stop, the stop sign symbol was always displayed yellow - so the system knew it should deactivate.
Do you have the voltage meter on the dash? If not do so and it may answer a few of your questions? Basically it's probably down to the terrible batteries that Porsche use as standard. How old is your car? If it's a Moll battery than that's probably the answer, though the Banner batteries don't seem much better.
My wife's Mokka can be stopped for minutes at a time, my 981 rarely lasts more than about 20 seconds, I just turn it off now. Any fuel saving is more that offset by lower battery (and maybe starter motor) life.
My wife's Mokka can be stopped for minutes at a time, my 981 rarely lasts more than about 20 seconds, I just turn it off now. Any fuel saving is more that offset by lower battery (and maybe starter motor) life.
Yes I have the voltage meter but it never shows anything out of the ordinary.
Car is almost 4 years old but you are probably right, the s
tty Moll battery is probably to blame.
I wonder how it would work with a decent Bosch example. My friends Mondeo will stop for several minutes at a time, providing a genuine fuel saving at stubborn traffic lights or jams.
Car is almost 4 years old but you are probably right, the s
tty Moll battery is probably to blame.I wonder how it would work with a decent Bosch example. My friends Mondeo will stop for several minutes at a time, providing a genuine fuel saving at stubborn traffic lights or jams.
I find the volt meter showing upper 12v when stop start kicks in, but this soon dives to low 12v even with seemingly little electrical draw, once the voltage dips under 12v the engine kicks back in. This implies to me that the battery just can't maintain any sort of load, I have no issues with starting or any other electrical gremlins though.
In theory AGM batteries should be able to take deeper discharge cycles and a consistent low charge state without any long term damage (these scenarios would kill a standard lead acid battery), but I'm not convinced the Banner/Moll ones are great. My Banner battery is about double the size of the one in my wife's Mokka and I don't see much additional electrical draw (hers also has heated seats/steering wheel/mirrors/back window etc etc) so how come hers seems to maintain decent voltage for several minutes with no problems?
In theory AGM batteries should be able to take deeper discharge cycles and a consistent low charge state without any long term damage (these scenarios would kill a standard lead acid battery), but I'm not convinced the Banner/Moll ones are great. My Banner battery is about double the size of the one in my wife's Mokka and I don't see much additional electrical draw (hers also has heated seats/steering wheel/mirrors/back window etc etc) so how come hers seems to maintain decent voltage for several minutes with no problems?
From memory it works of several parameters but if the car is in Sport + it won't turn off at all.
Likewise if the engine oil is hot (having been driven hard), battery voltage is low or high demand on electrical system, HVAC system demands also affect whether the engine shuts down or not.
Personally it is the first button I push in any car when I start it up, i like the engine to run until I turn it off myself.
Likewise if the engine oil is hot (having been driven hard), battery voltage is low or high demand on electrical system, HVAC system demands also affect whether the engine shuts down or not.
Personally it is the first button I push in any car when I start it up, i like the engine to run until I turn it off myself.
NAS90 said:
From memory it works of several parameters but if the car is in Sport + it won't turn off at all.
Likewise if the engine oil is hot (having been driven hard), battery voltage is low or high demand on electrical system, HVAC system demands also affect whether the engine shuts down or not.
Personally it is the first button I push in any car when I start it up, i like the engine to run until I turn it off myself.
Those are true but my point is its operation is appears random, e.g. same commute every day and different results with start stop.Likewise if the engine oil is hot (having been driven hard), battery voltage is low or high demand on electrical system, HVAC system demands also affect whether the engine shuts down or not.
Personally it is the first button I push in any car when I start it up, i like the engine to run until I turn it off myself.
It is a very strange piece of kit on Porsches.
My 981 doesn't get used much and over winter was once per week maximum. I charged the battery once over 2 nights and a full day so around 30 hours. The next time I drove the car it was start stopping more than ever. It was also coasting more too - where the pdk goes to idle if you lift off the throttle. So yes I would say this is more to do with the charge in the battery and number of toys draining it.
Auto Start Stop Function
Auto Start Stop Function1:17
The engine stops automatically when the vehicle is stopped, e.g. at traffic lights or in a traffic jam. In this way, the Auto Start Stop function helps to save fuel.
The ignition stays on even when the engine switches off automatically. All functions are still available.
Preconditions for stopping the engine automatically
Auto Start Stop function is switched on.
Driver detected: driver’s seat belt fastened and driver’s door closed.
Move PDK selector lever to the D, N or P position, or to manually selected gear 1 or 2, or move gear lever to neutral without pressing the clutch pedal.
Engine, transmission and battery are at operating temperature.
Vehicle was driven at a speed of more than approx. 2 km/h (1 mph) for at least 1.5 seconds since the engine last stopped automatically.
Manual transmission: Stopping and starting the engine
Stopping the engine
The Auto Start Stop function stops the engine as soon as the vehicle stops moving.
Use the footbrake to stop the vehicle.
The engine will stop if the gearshift lever is in neutral and the clutch pedal is no longer depressed.
Starting the engine
The Auto Start Stop function starts the engine:
Fully depress the clutch pedal and engage gear from neutral.
You can drive off normally.
PDK: Stopping and starting the engine
Stopping the engine
The Auto Start Stop function stops the engine as soon as the vehicle stops moving.
Use the footbrake to stop the vehicle.
Keep the footbrake pressed.
or
Move PDK selector lever to position P.
Starting the engine
The Auto Start Stop function starts the engine:
In PDK selector-lever position D, N or manually selected driving range 1 or 2
release the footbrake.
or
Press the accelerator.
or
Move PDK selector lever to position R.
You can drive off normally.
Information
The engine will start automatically in certain situations, e.g. if the vehicle starts rolling, to ensure passenger comfort via air conditioning, if the brake vacuum is reduced, or if the engine has stalled in the case of vehicles with manual transmission.
Starting the engine after leaving the vehicle
If the vehicle is left after an automatic stop, in order to open the garage door, for example, there will be an automatic engine start if the following conditions are met:
Selector-level position P engaged.
the driver gets in again within 30 seconds
seat belt fastened
Selector-lever position D engaged and
brake released
If one of these requirements is not met, the engine has to be started manually. The message “Please start engine manually” will appear on the multi-function display in the instrument panel.
Please refer to chapter “OVERVIEW OF WARNING AND INFORMATION MESSAGES”.
Exceptions for the Auto Start Stop function
The Auto Start Stop function is not available in the following situations, e.g.:
When “Sport” or “Sport Plus” mode is activated.
When PSM is off.
In Manoeuvring mode.
When A/C MAX mode is activated.
When the “Windscreen defrost” function is active.
At altitudes of more than approx. 3,000 metres.
After engaging a gear without actuating the clutch during automatic stopping of the engine.
The Auto Start Stop function is available with limited functionality in the following situations, e.g.:
If the air conditioning or passenger compartment heating is operated at a high setting or if the defrost function is run for long time periods.
If the battery charging condition is low.
On upward or downward slopes.
During internal vehicle test procedures, e.g. automatic engine checks.
In the case of excessively low exterior or battery temperature.
Information
If one of these situations arises after the engine has stopped automatically, the engine can be restarted automatically.
Switching Auto Start Stop function and coasting mode on and off
Switching off
Press the button.
The indicator light on the button lights up.
Automatic stopping of the engine is suppressed and coasting mode is switched off.
Switching on
Press the button.
The indicator light on the button goes out.
The engine is automatically stopped when the vehicle stops and coasting mode is switched on.
Please refer to chapter “DRIVING IN COASTING MODE”.
Auto Start Stop function display
Automatic engine stop and restart readiness
If the engine was stopped automatically by the Auto Start Stop function and if the driver is detected in the vehicle (driver’s seat belt fastened and driver’s door closed), the indicator light on the multi-function display in the instrument panel will light up green.
No engine stop or restart readiness
If the Auto Stop function is not available or if no driver is detected in the vehicle after the engine has stopped automatically (driver’s seat belt not fastened or driver’s door open), the indicator light on the multi-function display in the instrument panel will light up yellow when the vehicle is stationary.
The Auto Start Stop system has detected that:
At least one precondition for stopping the engine automatically is not met.
or
There is at least one exception for the Auto Start Stop function.
Please refer to chapter “PRECONDITIONS FOR STOPPING THE ENGINE AUTOMATICALLY”.
Please refer to chapter “EXCEPTIONS FOR THE AUTO START STOP FUNCTION”.
Information
If the indicator light in the multi-function display continuously lights up yellow when the vehicle is stopped and if the engine does not stop regularly when the vehicle is stopped despite the fact that the preconditions for stopping the engine automatically are met, have the Auto Start Stop system checked the next time you visit the workshop.
Fault reporting
If there is a fault, the warning message “Start/Stop operation deactivated” will appear on the multi-function display in the instrument panel.
Have the fault corrected at a specialist workshop.
We recommend that you get a Porsche partner to do this work as dealers have trained workshop personnel and the necessary parts and tools.
Auto Start Stop Function1:17
The engine stops automatically when the vehicle is stopped, e.g. at traffic lights or in a traffic jam. In this way, the Auto Start Stop function helps to save fuel.
The ignition stays on even when the engine switches off automatically. All functions are still available.
Preconditions for stopping the engine automatically
Auto Start Stop function is switched on.
Driver detected: driver’s seat belt fastened and driver’s door closed.
Move PDK selector lever to the D, N or P position, or to manually selected gear 1 or 2, or move gear lever to neutral without pressing the clutch pedal.
Engine, transmission and battery are at operating temperature.
Vehicle was driven at a speed of more than approx. 2 km/h (1 mph) for at least 1.5 seconds since the engine last stopped automatically.
Manual transmission: Stopping and starting the engine
Stopping the engine
The Auto Start Stop function stops the engine as soon as the vehicle stops moving.
Use the footbrake to stop the vehicle.
The engine will stop if the gearshift lever is in neutral and the clutch pedal is no longer depressed.
Starting the engine
The Auto Start Stop function starts the engine:
Fully depress the clutch pedal and engage gear from neutral.
You can drive off normally.
PDK: Stopping and starting the engine
Stopping the engine
The Auto Start Stop function stops the engine as soon as the vehicle stops moving.
Use the footbrake to stop the vehicle.
Keep the footbrake pressed.
or
Move PDK selector lever to position P.
Starting the engine
The Auto Start Stop function starts the engine:
In PDK selector-lever position D, N or manually selected driving range 1 or 2
release the footbrake.
or
Press the accelerator.
or
Move PDK selector lever to position R.
You can drive off normally.
Information
The engine will start automatically in certain situations, e.g. if the vehicle starts rolling, to ensure passenger comfort via air conditioning, if the brake vacuum is reduced, or if the engine has stalled in the case of vehicles with manual transmission.
Starting the engine after leaving the vehicle
If the vehicle is left after an automatic stop, in order to open the garage door, for example, there will be an automatic engine start if the following conditions are met:
Selector-level position P engaged.
the driver gets in again within 30 seconds
seat belt fastened
Selector-lever position D engaged and
brake released
If one of these requirements is not met, the engine has to be started manually. The message “Please start engine manually” will appear on the multi-function display in the instrument panel.
Please refer to chapter “OVERVIEW OF WARNING AND INFORMATION MESSAGES”.
Exceptions for the Auto Start Stop function
The Auto Start Stop function is not available in the following situations, e.g.:
When “Sport” or “Sport Plus” mode is activated.
When PSM is off.
In Manoeuvring mode.
When A/C MAX mode is activated.
When the “Windscreen defrost” function is active.
At altitudes of more than approx. 3,000 metres.
After engaging a gear without actuating the clutch during automatic stopping of the engine.
The Auto Start Stop function is available with limited functionality in the following situations, e.g.:
If the air conditioning or passenger compartment heating is operated at a high setting or if the defrost function is run for long time periods.
If the battery charging condition is low.
On upward or downward slopes.
During internal vehicle test procedures, e.g. automatic engine checks.
In the case of excessively low exterior or battery temperature.
Information
If one of these situations arises after the engine has stopped automatically, the engine can be restarted automatically.
Switching Auto Start Stop function and coasting mode on and off
Switching off
Press the button.
The indicator light on the button lights up.
Automatic stopping of the engine is suppressed and coasting mode is switched off.
Switching on
Press the button.
The indicator light on the button goes out.
The engine is automatically stopped when the vehicle stops and coasting mode is switched on.
Please refer to chapter “DRIVING IN COASTING MODE”.
Auto Start Stop function display
Automatic engine stop and restart readiness
If the engine was stopped automatically by the Auto Start Stop function and if the driver is detected in the vehicle (driver’s seat belt fastened and driver’s door closed), the indicator light on the multi-function display in the instrument panel will light up green.
No engine stop or restart readiness
If the Auto Stop function is not available or if no driver is detected in the vehicle after the engine has stopped automatically (driver’s seat belt not fastened or driver’s door open), the indicator light on the multi-function display in the instrument panel will light up yellow when the vehicle is stationary.
The Auto Start Stop system has detected that:
At least one precondition for stopping the engine automatically is not met.
or
There is at least one exception for the Auto Start Stop function.
Please refer to chapter “PRECONDITIONS FOR STOPPING THE ENGINE AUTOMATICALLY”.
Please refer to chapter “EXCEPTIONS FOR THE AUTO START STOP FUNCTION”.
Information
If the indicator light in the multi-function display continuously lights up yellow when the vehicle is stopped and if the engine does not stop regularly when the vehicle is stopped despite the fact that the preconditions for stopping the engine automatically are met, have the Auto Start Stop system checked the next time you visit the workshop.
Fault reporting
If there is a fault, the warning message “Start/Stop operation deactivated” will appear on the multi-function display in the instrument panel.
Have the fault corrected at a specialist workshop.
We recommend that you get a Porsche partner to do this work as dealers have trained workshop personnel and the necessary parts and tools.
Has anyone seen any value to stop start in their Porsche? I ran some brief tests in mine and wasn't able to see any difference and that's with a V8. (We celebrated 20mpg,US, at the weekend on a long run at 80)
It sounds like stop start is accomplishing the opposite of its intention if people are hitting sport to avoid it. I also find my car too responsive in sport for normal driving. But, that might be because it is a GTS so it may be a little more eager.
I'm lucky, I have a US car so it is one press and done. Every loaner I've had has already had the stop start turned off. I spoke to the dealership and they said they turn it off on all their cars.
It sounds like stop start is accomplishing the opposite of its intention if people are hitting sport to avoid it. I also find my car too responsive in sport for normal driving. But, that might be because it is a GTS so it may be a little more eager.
I'm lucky, I have a US car so it is one press and done. Every loaner I've had has already had the stop start turned off. I spoke to the dealership and they said they turn it off on all their cars.
h0b0 said:
Has anyone seen any value to stop start in their Porsche? I ran some brief tests in mine and wasn't able to see any difference and that's with a V8. (We celebrated 20mpg,US, at the weekend on a long run at 80)
It sounds like stop start is accomplishing the opposite of its intention if people are hitting sport to avoid it. I also find my car too responsive in sport for normal driving. But, that might be because it is a GTS so it may be a little more eager.
I'm lucky, I have a US car so it is one press and done. Every loaner I've had has already had the stop start turned off. I spoke to the dealership and they said they turn it off on all their cars.
If you are in crap-traffic like in central London,daily, it's pretty useful. The engine gets quite hot in these cars and serious congestions where you have to wait 5-6 minutes than start to go only 10 metres for almost an hour, is a serious damage to your car. (not only cooling system, but oil temperature also gets very hot if you do not have start/stop so in long term it's not good for the engine)It sounds like stop start is accomplishing the opposite of its intention if people are hitting sport to avoid it. I also find my car too responsive in sport for normal driving. But, that might be because it is a GTS so it may be a little more eager.
I'm lucky, I have a US car so it is one press and done. Every loaner I've had has already had the stop start turned off. I spoke to the dealership and they said they turn it off on all their cars.
The best solution is to get rid off these half-empty over-crowded routemasters, so we might have some normal traffic conditions again. :/
Edited by ooid on Wednesday 26th April 00:56
ooid said:
The engine gets quite hot in these cars and serious congestions where you have to wait 5-6 minutes than start to go only 10 metres for almost an hour, is a serious damage to your car. (not only cooling system, but oil temperature also gets very hot if you do not have start/stop so in long term it's not good for the engine)
Is there actually any evidence for that? Sounds like a very big design flaw if true but sounds like it would be a huge scandal to me considering people own these cars in say Arizona/Middle East etc.Gassing Station | Porsche General | Top of Page | What's New | My Stuff