What could this be?

[Froglet]

So, I have had an E90 M3 (DCT) for about a week now and have noticed an interesting thing. For the most part, it drives great. But sometimes there is something funny.

Imagine I drive 80 on a long straight road and have been doing so for quite a while without accelerating or slowing down. Then, I decide to accelerate and push the pedal about 50% and nothing really happens (no acceleration and no downshifts). It seems to gurgle and be confused as to what to do. Then, when I press it slightly more (75%) all of a sudden it does downshift and takes off really quickly…

I’m not sure what this can be, but the throttle response seems a bit off here. I have read about some people with the same observation and they said it is something related to the DCT and its software. Others say that it is a normal thing… Again other people have experienced the same as I described but also that the car sometimes stalls at traffic lights (this I have not experienced)…

Has anyone had this and how have you solved it? Or is it a normal thing?

[deepocean2009]

Try to contact [MENTION=395]shak[/MENTION] octan garage for software update

[Froglet]

Yeh, I wanted to ask some advice regarding that as well...

My car has several Dinan parts (Air Intake and Underdrive Pulley) and received Dinan DKG Software (Engine and Gearbox tune) about 500km before I bought it. If I would go for an update at Shak wouldn't it overwrite what had previously been installed? If so, I'm not sure that would be the best thing to do... If it is indeed software related, I guess it would be best to back the place where they did all this Dinan work, right?

Thanks

[deepocean2009]

So i guess ur tune is still under warranty as you still 500 km only,better you go back to the tuning shop let him reflash to the stock if the problem solved so its a tuning issue

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I forget to ask this is happen in all driving or with power on? Might be transmission ratio?

[RAFiK]

Could be a faulty TPS (Throttle Position Sensor) ?

And yes, a DCT Software would overwrite your Dinan Software.

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After doing a quick research, I think this could be a DCT software issue. That means DINAN's software is based on the old DCT software. I guess you should contact them and ask for an updated DCT software or get the latest stock DCT software.

[Hasan Shaikh]

I always thought it was normal. It will not downshift unless you press the throttle beyond a certain threshold.

[RAFiK]

That's not the case for the 7-Speed DCT.

[Hasan Shaikh]

That's not the case for the 7-Speed DCT.

So, it just downshifts as soon as you touch the pedal? Doesn't take into consideration your speed or throttle position or the gear you are in?

[RAFiK]

So, it just downshifts as soon as you touch the pedal? Doesn't take into consideration your speed or throttle position or the gear you are in?

The DCT is very responsive, it is not complicated rocket science. It is just much quicker than any SMG Transmission. It definitely should down shift as soon as you cross the 25% threshold.

The problem here and as people described it and I'm quoting:

The DCT transmission seems to have trouble figuring out what gear to select because when you step on the gas to accelerate, there is a very significant delay in the onset of power- up to 2-3 seconds. By this time, the driver is usually really digging into the throttle. The transmission finally picks a gear, which results in the car suddenly lurching forward, sometimes invoking the anti-skip control.

[Hasan Shaikh]

Ok. Now, I understand. Thanks

Still, don't understand why one would run a DCT in auto. :)

[Froglet]

The DCT is very responsive, it is not complicated rocket science. It is just much quicker than any SMG Transmission. It definitely should down shift as soon as you cross the 25% threshold.

The problem here and as people described it and I'm quoting:

Yeh, that part you quoted seems about right. It doesn't always happen, just occasionally. What was the proposed solution to where you found this quote? Was it DCT?

Thanks

[Hasan Shaikh]

DCT stands for Dual Clutch Transmission.

I would drive the car in manual mode rather than trying to fix something like this.

The SMG III has a dreadful auto mode. I have never driven it in auto. Ever.

[RAFiK]

Yeh, that part you quoted seems about right. It doesn't always happen, just occasionally. What was the proposed solution to where you found this quote? Was it DCT?

Thanks

A Software update was the solution. What model is your car if I may ask? 08 09 ?

[Froglet]

A Software update was the solution. What model is your car if I may ask? 08 09 ?

It's from 2009. I'll go an investigate the matter further and let you know what the solution has been

Thanks!

[RAFiK]

Update us please and good luck with it!