Thread: Delay in power when accelerating from low speed

Originally Posted by Mike_S

My petrol V8's the same, well certainly similar.

It's to do with the gearbox more than the engine and to overcome it, I'll drive it in sport and select the gears myself, that way it's always ready to go. The actual feeling is like a large 'dead spot' in the middle of the pedal travel if you're just trundling along on a light throttle, then go to accelerate. Either that or say, coming up to a junction and the box isn't in the right gear if you suddenly apply the throttle, meaning there's a lag whilst it gets the right gear then gives it the beans.

Annoying, but I've got used to it and know when to use the box myself now.

Oh well, good to see LR have been consistant on this one....LOL!!!

Hi guys - I have recently joined the forum because I'm considering trading my 3l GU Patrol on a D4 (my wife doesn't like the TRUCK).
I took one for a test drive today and have to admit the D4 3.0 is a VERY impressive machine, EXCEPT for a 'no power' event in the middle of a sharp left hand turn. I entered the intersection on light throttle and when I attempted to accelerate out of the corner there was NO response for several seconds. Having read this thread I think that the DSC and perhaps the 'thinking gearbox' considered that I shouldn't apply more power until I unwound the amount of left hand steering lock. I hope this is a problem that can be overcome with experience - other wise I might keep the dumb Patrol (at least it doesn't try and second guess me).
John

I used to get annoyed about this when I first got my D3. I soon learned to change the behaviour of my right foot - and also move the gear lever to "sport" mode. If it is really bad, use manual mode. I seem to recall that the learning behaviour is for the first 500km after it is reset, and you are not meant to use sport in that time.

Adaptive ZF gear box,stops double guessing when it learn what you want to do, readapts again when towing, it just needs a good test drive without the salesman.
Cheers Ken

I too have noticed this lag. It must be the transmission. Reason for this is I get turbo lag, but this is not the same feeling.

Just this weekend I was playing around with the sport shift as I spent the weekend mostly in the bush, much of it in low range. I found shifting manually was so much more responsive when needed. In auto/drive, the gear selection going up steep inclines was too high so the vehicle slowed, then changed down to give traction and more power to get up the tracks. I even got the rear end to power out on a turn and actually got it into a controlled slide then accelerated out with heaps of wheel spin. Never had it do that before.
When I got back to main roads, the car reacted very much like a different car than normal as it was very fast on acceleration without lag. Just a push on the pedal gave instant response. This is not normally how it drives. I assume after a weekend of driving this way (manual shift) the adaptive gearbox, then took it that my driving style had changed and adapted accordingly.

Don't know if this is a good or bad thing.
Don't know if I am right in the explanation above but certainly what I have just observed.

When I know I need to take off quickly all I do it push it across into sport mode and then I don't have any problems. In sport mode you can even notice the down changes in the gearbox when you slow down and you actually even seem to get a little engine braking.
I don't bother changing manually - even though this is the first auto I've owned I've adapted very quickly and figure why bother considering this gearbox does everything so well without me interferring!

Originally Posted by johneyles

Hi guys - I have recently joined the forum because I'm considering trading my 3l GU Patrol on a D4 (my wife doesn't like the TRUCK).
I took one for a test drive today and have to admit the D4 3.0 is a VERY impressive machine, EXCEPT for a 'no power' event in the middle of a sharp left hand turn. I entered the intersection on light throttle and when I attempted to accelerate out of the corner there was NO response for several seconds. Having read this thread I think that the DSC and perhaps the 'thinking gearbox' considered that I shouldn't apply more power until I unwound the amount of left hand steering lock. I hope this is a problem that can be overcome with experience - other wise I might keep the dumb Patrol (at least it doesn't try and second guess me).
John

Hi Mate,

as stated in the previous threads there is no turbo lag in the 3.0L, it is the transmission. It is not a common occurance and once you get used to it, and think about it, a quick flick to Sports is all it takes to prevent it...in fact I don't even know how I overcome it in most cases 'cause it's become automatic...but I'm certain I just know it 'may' happen and adjust how I drive.

You'd be seriously robbing yourself if you let this stop you buying the car....

D4 to Patrol...sorry mate, no comparison.

Cheers,

Kev.

It's the auto, not the engine. It is slow to decide to change down at times, and where you may particuarly find a problem is roundabouts, where you slow down sharply on entry, then decide to go and the car is reluctant to hurtle off. The solution is either Sport or Command Shift mode, or even better change the driving style so you don't get into situations where you need sudden throttle application, which also pays fuel consumption dividends too. The slow-in, fast-out maxim works really well on road.

In the hopefully rare cases where do get caught out remember to floor it even if you don't need max power, and then lift as soon as the car takes off as opposed to simply apply the amount of throttle needed and hope. I don't see a need for permanent Sport mode, you'll just use extra fuel as it holds on to gears longer.

Around town the problem doesn't bother me at all, but it does offroad where the car is a shocker on steeper hills in Drive, let's say the auto is in perhaps 3rd and later it decides to change to second. It takes forever, and the momentum is largely lost, then a change and a surge of traction-losing power. This is why I recommend Command Shift be used for hill ascents rather than relying on the auto.

Another problem is on fast winding roads where the car can be slow to change down for a bend exit, but that's only really a problem if you're really hustling or if it's a very slow, uphill, tight road. If you are then Sport Mode helps, and ultimately Command Shift too which is even better and permits some use of engine braking.

Do not switch DSC off to solve the problem. It probably isn't causing an issue to begin with, as you'd need to be on a very slippery surface for it to kick in under straight-line acceleration. If you are fanging around corners and throttle is being retarted by DSC you'll know it because you'll hear it working and see the dash light. If you turn DSC off you're making the car less safe, simple as that as you remove a useful on-road safety net. In low range situations that's a different matter. DSC can also show up cornering errors, where non-DSC cars would simply slip a little and permit throttle to be applied DSC will (via CBC as well) electronically correct the line for you.

JohnEyles - in a stability control car (eg, DSC) if you apply power around a corner whilst holding or increasing lock the DSC will often kick in as the coomputer realises the accleration at that radius will very soon overwhelm the tyres' traction, and pre-empetively restrict power. The solution, as you noted, is to ensure that by the time you are applying power to exit the bend you are *unwinding* lock, even gently, doesn't have to be straight, but should be unwinding and to do that you typically need a slower entry where you get close to the apex so there's room to unwind and accelerate. This also helps with the classic problem of wandering over the white lines halfway around the corner due to a too-high entry speeds and then needing to wash off speed mid-corner...not a good idea. Being very smooth and gentle is also essential.

The solution is to take a better line through the corners, DSC in a Discovery is no barrier to rapid progress at all and I always have mine on unless I'm in low range or in raised-suspension situations.

If this sort of cornering technique interests anyone that I recommend a study of any racing techniques manual, and even better, BMW Driver Training which is not cheap but it is the best I've seen.