VW disable start/stop eco stupidity

tossy

Since this thread was started i've bought a VW with stop/start i changed one of the set parameters of one of the prerequisites it looks for (battery voltage) and now its disabled full time.

As far as i know it checks outside temp not engine temp.

John.G

tossy wrote: »

Since this thread was started i've bought a VW with stop/start i changed one of the set parameters of one of the prerequisites it looks for (battery voltage) and now its disabled full time.

As far as i know it checks outside temp not engine temp.

Yes, I think outside air temperature is considered but this what it states in my users manual.....period.

Important preconditions for automatic engine switch-off
•The driver is wearing their seat belt.
•The driver door is closed.
•The bonnet is closed.
•The factory-fitted towing bracket is not attached electrically to a trailer.
•A minimum engine temperature has been reached.
•The vehicle has been moved since the engine was last switched off.

John.G

tossy wrote: »

Since this thread was started i've bought a VW with stop/start i changed one of the set parameters of one of the prerequisites it looks for (battery voltage) and now its disabled full time.

As far as i know it checks outside temp not engine temp.

Re 2000 petrol Polo and start/stop parameters, got hold of a VCDS Hex-V2 this am and had a brief look at parameters, there is no mention of engine/coolant temperature and this is what I saw... (Wonder is this the same (daft) case in all VAG petrol engine vehicles.)

Deactivation Stop/start: default: "Mode not active", Other modes were, "Stop Release", "Stop prohibition:No start request", "Start Request" and "System Malfunction".

Start/Stop Start voltage limit: default: 7.6V.
Start/Stop Start minimum ambient temperature: default: -50C
Start/Stop Start maximum ambient temperature: default: -50C

I didn,t change any parameter but I think that 12.1V is the maximum settable limit so don't see how this would help inhibit the stop as the charging voltage will be well above this even when idling with a lot of electrical auxiliaries on but it will restart obviously if the voltage drops below this with a stopped engine.
The minimum settable ambient temperature is -50C and the maximum settable temperature is +50C.

colm_mcm

I think mine looks for a minimum voltage of 15v now.

Needless to say it never turns off the engine!

30 second job with OBDeleven.

John.G

I thought the VCDS showed 7.6V but I also saw 12.1V which is the more likely (default) setting for inhibiting the stop/start, with 7.6V being the minimum, I don't want to inhibit the stop/start "permanently", its just that I find it unbelievable really that there doesn't appear to be any minimum engine coolant temperature setting.

Spook_ie

John.G wrote: »

I thought the VCDS showed 7.6V but I also saw 12.1V which is the more likely (default) setting for inhibiting the stop/start, with 7.6V being the minimum, I don't want to inhibit the stop/start "permanently", its just that I find it unbelievable really that there doesn't appear to be any minimum engine coolant temperature setting.

I seem to recall reading somewhere that it's go do with the air conditioning, I'd give it a whirl with the A/C on snd set to 20C +

Spook_ie

Spook_ie wrote: »

I seem to recall reading somewhere that it's go do with the air conditioning, I'd give it a whirl with the A/C on snd set to 20C +

Spook_ie wrote: »

I seem to recall reading somewhere that it's go do with the air conditioning, I'd give it a whirl with the A/C on snd set to 20C +

So I photographed the sequence I got over 25 minutes of driving on a cold night, the engine cold went off very quickly but it took nigh on 20 minutes before it decided I was warm enough set at 18C, turned the a/c upto 24C and the engine started with the engine must be on for AC message. If your stop start is active so quickly I would suspect a sensor fault somewhere

Can't get the photos up from mobile site I'll try later when I'm at home

Skyhawk1990

I have a 2014 Golf, I have it disabled permanently.

On one of the battery terminals, can't remember which one, there's a plug with two wires coming out of it. This is what reads the battery voltage for the auto stop/start. Unplug this and tape up the plug and the socket to help stop corrosion should you want to re-connect it.

This has no other effect on the car other than reading the battery voltage as zero so it just leaves the car running when stopped.

Just saw this was posted earlier in the thread 😂😂

John.G

I'm sorry but I think you are all are missing my point.... I don't want to permanently disable the stop/start, all I am asking is why the engine/coolant temperature reaching a minimum temperature on a PETROL POLO does not seem to play any part in its stop start philosophy, can or would someone please tell me if this is true of all petrol engined VAG cars or just drive one of them with AC or whatever switched off from a cold start and just see if the engine cuts out after stopping after driving for a few hundred meters or so, that's all I am asking.

zilog_jones

Does VCDS show exhaust or oil temperature? Seems a bit odd.

I assume your car has manual cabin heating controls, i.e. not automatic climate control? Maybe the heating would work better with climate control since it has no feedback loop (it doesn't know the cabin temp) without it.

Is there an exhaust heat recovery system? This is used in hybrids to speed up getting the engine up to temperature, not sure if start/stop cars have similar. Look for coolant pipes going to the exhaust somewhere.

John.G

This car has no AC but if the blower speed is increased to 4 (and maybe 3) it will restart the engine if stopped or inhibit it from stopping if running.
There is no exhaust heat recovery from what I can tell but it is possible that the coolant passes through a jacket in the exhaust manifold but no visible sign of this.
The oil temprature can be read with the VCDS and is also displayed on the screen but not until it reaches 50C, it lags the coolant temperature somewhat until engine up to normal operating temperature and then, depending on engine load will read ~ 88C to 100C.
I havn't looked for exhaust temperature in VCDS yet. This engine is just the basic 65 bhp normally aspirated model.