Evening all,

I've been lurking on the forum since I placed my order at the end of March and finally took delivery of my SE Business estate manual (MY17) at the end of July and have covered 1000 miles in it so far and love it. The car is back into the dealer this week as the memory function on the drivers seat hasn't worked from day 1. However, another problem has come to light and I was wondering if this problem has been encountered before (I've trawled previous threads but can't find anything similar).

 

Most of my day to day commuting doesn't warrant the use of the Cruise Control function so I leave it turned off (bottom lever on the left side of the steering wheel pushed all the way forward and the Active Cruise Control turned off symbol flashed up on the multi dot display) and the normal CC symbol also disappears from the dash. 

Now I sometimes find the car starts to speed up by itself and gains about 1MPH per second! It doesn't sound that dramatic but trust me, when you are in a moving queue of traffic you find the rear bumper of the car in front getting closer quicker than you anticipated! (especially since I know CC is turned off!).

I've narrowed down when this occurs and it's always when the car starts to slow down and the little arrow on the maxi dot display advises you to change down a gear ( 4->3 ) and the revs are ticking over at about 1100RPM. At this point if I do nothing the CC seems to cut in and the car starts to accelerate although no indication is displayed in the maxi dot to show CC has activated.

 

Hopefully the dealer will find a solution this week but I'd be interested to hear if others have experienced similar problems. 

 

Thanks in advance,

 

Steve

I've narrowed down when this occurs and it's always when the car starts to slow down and the little arrow on the maxi dot display advises you to change down a gear ( 4->3 ) and the revs are ticking over at about 1100RPM. At this point if I do nothing the CC seems to cut in and the car starts to accelerate although no indication is displayed in the maxi dot to show CC has activated.

 

So... the anti-stall doing its job then, perhaps? You're lugging the engine at 1,100rpm and the Maxidot is begging you to change. Eventually at just before idle it starts to add in its own fuel to stop the engine stalling. Sounds more likely than phantom cruise control, especially if it's only adding 1mph a second for - I imagine - a couple of seconds (I doubt you're sat idly waiting to rear end the car in front)? I may of course be wrong, and you may have some kind of faulty ACC with a mind of its own. But for my money, something like this is more likely, especially if it only happens under those circumstances. Easy fix - don't labour the engine and change into a suitable gear at the appropriate time. Hopefully the dealer confirms it's nothing sinister. 

Cheers for the speedy reply :-)

 

I don't normally labour the engine but sometimes you can read the road ahead and catch it just before the down shift is required. However, out of curiosity I found a quiet road on a local industrial estate and replicated the phenomenon and the car just kept accelerating! I do like the suggestion of the anti stall function and to be honest I didn't realise the vehicle had this (although my Mrs is a dab hand at managing to stall it!!!!). I'll check what the dealer says and post their reply.

 

Cheers, Steve.

Cheers for the speedy reply :-)

 

I don't normally labour the engine but sometimes you can read the road ahead and catch it just before the down shift is required. However, out of curiosity I found a quiet road on a local industrial estate and replicated the phenomenon and the car just kept accelerating! I do like the suggestion of the anti stall function and to be honest I didn't realise the vehicle had this (although my Mrs is a dab hand at managing to stall it!!!!). I'll check what the dealer says and post their reply.

 

Cheers, Steve.

 

Yeah pretty much every car for x decades has had it. It won't help when pulling away from a standing start (on most cars), but it will pile fuel in to stop a stall when you're driving and the revs have dropped for whatever reason... Good luck!  

I have tried to replicate this tonight and I could, when in the wrong gear at around 900rpm the anti stall or choke for the oldies kicks in spoiling up the turbo resulting in the car pulling its own weight with no pressure on the accelerator. These engines have enough torque to also pull them self along in any gear at rpm so low.

I was in 6th at 35mph (gear change suggestion shows 5th) and on a flat road the car pulled its self up to about 45moh before it stabilised at the peak speed for no throttle.

I think you are trying to drive it too soft and it's just pulling away on its self due to the above comments.

I'm a non turbo car you would of stalled.

Edited 16 August, 20169 yr by RickTT

Surely this is not good.

 

I drive my current manual lancer around town in most gears (its a diesel) at about 11/1400 revs.  It does not accelerate on me (VW engine).  I control the throttle even with CC on.

 

Would this condition be particular to auto/dsg only or is it prevalent amongst manuals as well ?

Surely this is not good.

 

I drive my current manual lancer around town in most gears (its a diesel) at about 11/1400 revs.  It does not accelerate on me (VW engine).  I control the throttle even with CC on.

 

Would this condition be particular to auto/dsg only or is it prevalent amongst manuals as well ?

Surely its manuals only. An auto i.e. DSG, would simply change down as necessary.

Its good, in fact its great as it prevents you from stalling.

With stop start, if you do manage to stall as I did yesterday, so long as you immediately depress the clutch, I like the fact that it'll restart for you without the driver needing to intervene with the ignition key.

Its good, in fact its great as it prevents you from stalling.

Its a nice to have in a long traffic que where you can sit in 1st /2nd gear at idle and potter along at 5-8mph.

Unfortunately, if you labour the engine so much that the car has to accelerate up to a constant idle rpm, then you will be lugging (labouring) the engine on min oil pressure (so wear is higher) and also it is likely that you will accelerate the damage to your dual mass flywheel.

I have been caught out a few times when a DPF regen has been in progress. Normally I would slow (in gear) down only braking as late as is safe to do so and declutching as the rpms reach 1000 rpm'ish. This is fine noramlly down to 800rpm but under regen conditions the rpm resting level is brought up to 1000rpm, therefore when I am braking in gear down to 1200rpm the car starts to inject fuel to prevent a stall. Like I said, this is the only time I find the car accelerating on its own.

The gear select is a little sensitive I find. If the road is flat'ish and traffic is moving well, if I can comfortably sit in 5th or 6th gear at 1100rpm on 10-30% throttle that hunky dory. The gear selector will normally tell me to change down a gear and that impacts on my ECO Greendrive score on Columbus!! It's very annoying but that is the nature of the beast.

All I would say is, don't labour engine and use the correct gear for the job and throttle position. No 100% throttles in 5th or 6th at 1000-1500rpm as that just isn't fair on the engine or gearbox.