Throttle response problems

[TX135i]

On four occasions this week, when trying to pull out into or across traffic, my car acts like it has no initial throttle response. So I push harder, maybe 1/2 to 3/4 pedal and it takes off like a bottle rocket. Took it in today for an oil change and to check this out, and of course they can't reproduce it. My car also had the stalling and fluctuating idle problem a few months back (still has fluctuating idle), and I was told at the time after bitching about it that the field rep said new S/W was being released in July to fix it. The same dumbass SA tells me today that there is no known S/W fix in work. I reminded him of the previous conversation and he acted like he had no idea. Pisses me off. But the reason for the post was to see if anyone was experiencing initial throttle response delays like this. Each time the car was warm, in sport mode (DCT) and from a dead stop. I actually felt a bit of panic because it was like there was no response at all, then boom! I love the car but this stupid crap and the dumbass SA are really getting to me!

[Upgrade+]

Glad you posted this. I'm having the same issue with my '11 135i. It usually happens when I come to partial stop. I didn't have this issue with my '08 135i nor my '07 335i. I'm assuming it may be because of the single turbo N55 engine having to scroll back up again. But shouldn't there be enough torque down low to negate this issue ( I may be wrong)? I was thinking of calling to get an appt to see if maybe a software update was needed. I read in a post about the JB+ being compatible to the N55 that had the old software. Possibly it may be the software? Let me know how this turns out on your end.

[TX135i]

Will do, and post whatever you find out too. It doesn't happen all the time, and didn't even start until recently and I got the car in Feb '12. They gave me some BMW fuel additive as 'good will' and said to try that. I will use it but don't think this is the issue. The SA said I have all the latest S/W.

[ILoveChess100]

Originally Posted by Upgrade+

Glad you posted this. I'm having the same issue with my '11 135i. It usually happens when I come to partial stop.

DCT? If not on a DCT then don't bother reading the rest as it probably means I am completely wrong LOL

I have the same thing, but I am pretty sure its because of the DCT, not because of engine or any other kind of lag. The brain for the tranny thinks that you are about to come to a complete stop based on the deceleration rate and current rpm so it begins to disengage the clutches altogether. If you don't manually downshift it to 1st prematurely while slowing down, the tranny would actually disengage from 2nd into neutral which means the first pack is still hooked to 3rd, the 2nd pack to 1st. If right at that time you hit the gas the tranny has to change the first pack to 1st, and then engage the clutch. Just this alone could take almost an entire second and if the hitting of the gas happens right when the disengage of both clutches is signaled then you have some extra lag to complete the disengage, plus change pack 1 into right gear, plus engage again.

You can try a couple of things to measure the lag of the tranny in these transition phases:
1. Manually downshift to first while slowing down. This will help quite a bit, but there will still be a small (theoretical) window for lag right around 3mph where the car still has to disengage, then reengage but at least pack 1 is in the right gear so you save 3rd to 1st switch.
2. Click your Upshifts 3times in a row really fast. Get up to about 4000 rpm in first and just go click click click as fast as you can on the upshift. 1 to 2nd will be super quick, anything after that will feel like an eternity because it does actually take an eternity. See DCTs are only quick when the tranny has already preselected the next gear. So always while acceleration a single upshift will be super quickly, but a double upshift will not be because it takes time to preselect the one gear over.
3. Following the same thinking, you can reproduce the same thing you are seeing when coming to a stop and whacking the gas pedal but completely confusing the tranny about your intentions. While accelerating the DCT preselects the next higher gear So go in second at really low RPM (where first is still possible), hit the gas while at the sime time you ask the tranny to downshift. It will prb take over 1.5s to do that.

btw of this assumes non-sport mode on. You can see this behavior in sport mode too, but the lag will be smaller because the clutches engage disengage much quicker.


@TX135i - When this happens to you on the freeway its possible that the transition from constant speed to slow acceleration makes the tranny preselect the next higher gear, the deeper pressure on the gas then asks it to downshift and voila you have the lag. This would only make sense if you are not in 7th already.

[MLemansDCT]

I'm experiencing the same problem on my 2011, E88 with DCT produced in 08/2010. Fluctuating idle, hesitation on start, and complete engine shut down twice when attempting to accelerate from stop. Went in for service and was told BMW was aware of complaint and was working on software fix for transmission computer. Supposedly SW fix was due out in mid July 2012. I have checked every two weeks since and still no software fix. Need to keep pressing your dealers so this gets more attention at BMW corporate.

[SinCalgary]

Originally Posted by TX135i

On four occasions this week, when trying to pull out into or across traffic, my car acts like it has no initial throttle response. So I push harder, maybe 1/2 to 3/4 pedal and it takes off like a bottle rocket. Took it in today for an oil change and to check this out, and of course they can't reproduce it. My car also had the stalling and fluctuating idle problem a few months back (still has fluctuating idle), and I was told at the time after bitching about it that the field rep said new S/W was being released in July to fix it. The same dumbass SA tells me today that there is no known S/W fix in work. I reminded him of the previous conversation and he acted like he had no idea. Pisses me off. But the reason for the post was to see if anyone was experiencing initial throttle response delays like this. Each time the car was warm, in sport mode (DCT) and from a dead stop. I actually felt a bit of panic because it was like there was no response at all, then boom! I love the car but this stupid crap and the dumbass SA are really getting to me!

Pasted this from a previous thread I replied to on this issue.

"I had these issues myself since getting the recall software update last year. AC on gave me idle surge when coming to a stop and the occasional stall as well. Throttle lag at a slow roll was downright dangerous. I took my car in three times in three weeks for it and on the final time they had the part in to replace my gearshift(Wasn't returning to neutral position when car was shut off/put in park)

In doing this the work order states "Removed Centre Console and replaced GWS, programmed and encoded whole vehicle and marked GWS as replaced control module."

This completely solved any issues I was having(though it made my iPod/AUX input not work). I now drive with AC on at all times with no idle/stall issues and have not had any throttle lag at a slow roll. The car sounds different with a bit quieter exhaust on cold start(even with golf tee) and I can hear the turbo spool up much louder now. Even better the old power is back if not even more and DSC is less intrusive, a 1-2 shift WOT will squawk tires and not chop the throttle unless you really push it. I am back to loving my car again!

A return visit to get my iPod working went fine and the car is still working well with no issues. I asked them for a software version and was told "ISTA/P V 2.46.6" Hope that helps some of you out, not sure if it is a Canadian only software version."

A few weeks later I am having other issues. Around 2500-3000 RPM in 3rd gear or higher I occasionaly get no throttle response at all. I can press the gas all the way(not past kickdown though) and the car does nothing. At first I thought it just wasn't building boost but there is no acceleration at all. Also got a temp warning once for about 5 seconds though my gauge was not past halfway. Radiator fan comes on pretty much constant and sounds like a plane taking off yet the temp gauge is still not over halfway. I dumped it at the dealer a few days but they can't fit me in until Friday I guess so I will update when I hear something. Not sure this new problem is related to the software update, at least I really hope it is not as the car was driving very well for a few weeks until this latest problem.

[TX135i]

In my case(s), all four times this week were from dead stop, not a slow roll. I instinctively looked the last 2 times and it was in D1. I always drive w/Sport mode on and it was in these cases.

[bogart]

The lag you are feeling is actually the traction control cutting in. If you have JB4 do some logs from a dead stop and traction control on. You will see that the pedal is being pressed, but the throttle and fuel are being cut. It's basically how the computer stops you from spinning the tires off a dead stop. Our cars have a lot of torque because of the turbo. Try this, hold down the DTC button on the dash until the triangle with the arrow going in a circle shows up on the dash. Then jam the gas from a dead stop. No more lag, but you will spin the tires like crazy. Be careful.

[alexmtl_135i]

Originally Posted by TX135i

On four occasions this week, when trying to pull out into or across traffic, my car acts like it has no initial throttle response. So I push harder, maybe 1/2 to 3/4 pedal and it takes off like a bottle rocket.

Oh yes. Had that as well, and I think it's DCT-related as well. I'm always driving in manual mode and downshifting to M1 before stopping helps a lot.

I believe this is a combination of DCT being silly and turbo lag. After installation of the Performance Exhaust I noticed less lag and I almost never have this problem. Or it could be placebo effect and me getting used to the car

[Upgrade+]

Ok, this definitely makes sense. I do have the DCT, so I'll try some of your suggestions out. I am curious about the manual based drivers out there and if they've had the same experiences. I hope this does not become our N55 problems like the "wastegate rattle/HPFP issues" that the N54's had to deal with.

Originally Posted by ILoveChess100

DCT? If not on a DCT then don't bother reading the rest as it probably means I am completely wrong LOL

I have the same thing, but I am pretty sure its because of the DCT, not because of engine or any other kind of lag. The brain for the tranny thinks that you are about to come to a complete stop based on the deceleration rate and current rpm so it begins to disengage the clutches altogether. If you don't manually downshift it to 1st prematurely while slowing down, the tranny would actually disengage from 2nd into neutral which means the first pack is still hooked to 3rd, the 2nd pack to 1st. If right at that time you hit the gas the tranny has to change the first pack to 1st, and then engage the clutch. Just this alone could take almost an entire second and if the hitting of the gas happens right when the disengage of both clutches is signaled then you have some extra lag to complete the disengage, plus change pack 1 into right gear, plus engage again.

You can try a couple of things to measure the lag of the tranny in these transition phases:
1. Manually downshift to first while slowing down. This will help quite a bit, but there will still be a small (theoretical) window for lag right around 3mph where the car still has to disengage, then reengage but at least pack 1 is in the right gear so you save 3rd to 1st switch.
2. Click your Upshifts 3times in a row really fast. Get up to about 4000 rpm in first and just go click click click as fast as you can on the upshift. 1 to 2nd will be super quick, anything after that will feel like an eternity because it does actually take an eternity. See DCTs are only quick when the tranny has already preselected the next gear. So always while acceleration a single upshift will be super quickly, but a double upshift will not be because it takes time to preselect the one gear over.
3. Following the same thinking, you can reproduce the same thing you are seeing when coming to a stop and whacking the gas pedal but completely confusing the tranny about your intentions. While accelerating the DCT preselects the next higher gear So go in second at really low RPM (where first is still possible), hit the gas while at the sime time you ask the tranny to downshift. It will prb take over 1.5s to do that.

btw of this assumes non-sport mode on. You can see this behavior in sport mode too, but the lag will be smaller because the clutches engage disengage much quicker.


@TX135i - When this happens to you on the freeway its possible that the transition from constant speed to slow acceleration makes the tranny preselect the next higher gear, the deeper pressure on the gas then asks it to downshift and voila you have the lag. This would only make sense if you are not in 7th already.

[bogart]

Originally Posted by alexmtl_135i

Oh yes. Had that as well, and I think it's DCT-related as well. I'm always driving in manual mode and downshifting to M1 before stopping helps a lot.

I believe this is a combination of DCT being silly and turbo lag. After installation of the Performance Exhaust I noticed less lag and I almost never have this problem. Or it could be placebo effect and me getting used to the car

The lag you are feeling is actually the traction control cutting in. If you have JB4 do some logs from a dead stop and traction control on. You will see that the pedal is being pressed, but the throttle and fuel are being cut. It's basically how the computer stops you from spinning the tires off a dead stop. Our cars have a lot of torque because of the turbo. Try this, hold down the DTC button on the dash until the triangle with the arrow going in a circle shows up on the dash. Then jam the gas from a dead stop. No more lag, but you will spin the tires like crazy. Be careful.

[alexmtl_135i]

Originally Posted by bogart

The lag you are feeling is actually the traction control cutting in. If you have JB4 do some logs from a dead stop and traction control on. You will see that the pedal is being pressed, but the throttle and fuel are being cut. It's basically how the computer stops you from spinning the tires off a dead stop. Our cars have a lot of torque because of the turbo. Try this, hold down the DTC button on the dash until the triangle with the arrow going in a circle shows up on the dash. Then jam the gas from a dead stop. No more lag, but you will spin the tires like crazy. Be careful.

I agree this could well be the software cutting the fuel, but I doubt this is because of traction control. This happens on very partial throttle (from 0 to 20%), and the behaviour (nothing happening and then suddenly a BIG surge of power) seem to be contrary to the principle of traction control.
And the traction control light doesn't show up on the dash.

I'll give it a try tonight with traction control disabled and see if that changes anything. But then I don't have the issue so often any more, so we'll see.

That been said, I strongly believe this has to do with software controlling the fuel delivery and the clutch actuation. Maybe if we all raise this issue with our dealer they could do something about it, if it's only software that should be a cheap easy fix for them.

[ParkNuts]

I've participated in most threads concerning throttle lag and DCT. It's definitely not traction control. That would be easy to explain and in these scenarios hardly any throttle is involved. It's from a slow roll, like rolling a stop sign. Many with DCT have this issue. I've taken my car in countless times for it and finally about a month ago my dealer told me there was a software fix in the works. I haven't had much time to take my car in but will be doing so shortly and reporting back with any information I get.

[JeremyN55]

i have a 2012 135i with PPK, intake and exhaust and my car hesitates when i full throttle it from a dead stop! it sucks when your racing it cause the other car has 5 cars on me before my car even moves! it feels like my 3200 stall in my pontiac!

[bogart]

You also have to remember that the computer is also saving your clutches from unnecessary wear.

It really has nothing to do with the transmission itself. We all know how quick the DCT can respond.

So I attribute it to BMW software that's causing the lag issue from a dead stop and or slow roll.

For instance, on the highway today in rush hour traffic. Cruising at about 10-15 mph in 1st gear. Seeing an opening in my mirror, turn the wheel and give it gas.... nothing. Almost got hit and had to turn back into the lane. Tried it again with a little more of a running start to get the turbo spooled up and it was a piece of cake.

Just plain dangerous in my opinion. There's no reason it should do that.

From a dead stop I can understand or when you roll to a stop/slow roll and then take off from a stop sign... only because the transmission does go into neutral even though it says you are in 1st or 2nd gear, and then takes a second to realize you aren't stopping for good. Kind of like someone explain earlier.

[Zombie1]

You guys are scaring me about getting a DCT....areany of you considering getting rid of the car cause of these problems? also is this issue in any other of bmws dct z4,335is

[JeremyN55]

I also tried to power brake it from a dead stop and it cuts the power, even with the E brake! I disconnected the brake sensor behind the pedal and brake light and it still does the samething. Even when brake boosting from a roll it cuts the power. Any info on this?

[Weasel410]

I took mine into Crevier about a month ago with the same complaint and they updated my DCT and ECU. They said it also reset my adaptations. I haven't had this issue since!

[CrustyNoodle]

I think the lag you are describing is due to the transmission ECU trying to be gentle in releasing the clutch so that you don't get a jerky transition from a slow roll to accelerating again. No doubt they could make it quicker but the question is will it compromise smoothness?

[TX135i]

Each time I have had the issue it was from a dead stop and after sitting there a short time waiting on traffic. I don't see how it could be tranny related in that case, but I also don't understand if it is a software issue, how it could be so intermittent.

[Zombie1]

Can we get some videos of this thig up I'd like to see it in action wen it happens, really want this car with dct just need to c if it's as bAd as it sounds

[TX135i]

Just happened AGAIN, this time while I was crossing traffic in front of a cop. So when I pressed harder it shot across the intersection like a scalded dog. Damn, this pisses me off.