Hesitation when accelerating ?

coupe-sport

Member
 Hampshire
My Z's just done over 6k miles now. I've always put a hesitation when accelerating hard, changing gear and then putting my foot down again to just be down to me, but i've noticed lately that its only when the fuel gauge is under 1/2 full.

Now is this just a coincidence or does anyone else get this ?

Car is running fine otherwise and is running on V-Power at the mo.

Thanks in advance

James
 
You always run on V Power James? I've posted before, but my old 3.0 was very susceptible to fuel quality, it ran so noticeably better on something with higher octane. Is it just in the higher gears?
 
Have you tried turning DSC off?

I presume you're talking about full-throttle acceleration - the DSC on my M is very conservative, so much so that it will cut in at any slight opportunity and make acceleration anything but smooth. Most of the time the first thing I do is hit the DSC button after I start the car, unless I'm tired or it's pissing down with rain...
 
There's no flashing of the traction control light when it does it. I've come off roundabouts full throttle with the light flashing and i can feel it limiting the power but this is more of a jerk. I don't normally notice it but when i do it always seems to be when the fuel gauge is reading under 1/2 full.

Mike - its been running on V-Power for the last few tankfulls and Tesco99 before that. Doesn't seem to make a difference.

I'll try it with DSC off and see what that does.

Cheers folks

James
 
I've felt the DSC limiting power or pulling at the brakes without flashing the dash light at me before though. I suppose give it a go - one more thing to rule out at least....
 
sixspeed said:
I've felt the DSC limiting power or pulling at the brakes without flashing the dash light at me before though.

me too.. particularly with the steering non-straight.. it seems to limit power when the steering is turned then doesn't show the light.. can be wierd coming up of junctions..
 
Thanks folks. Its not traction control as i can feel that happening and its much more subtle (car feels like its holding back). It's on Tescos 99RON for a few tankfulls and hasn't done it over the last week but it'll be interesting to see today if it returns when the fuel drops to under half full in the tank.

Cheers

James
 
I have the same but it's only occasionally and I can't find any pattern (DSC on/off, fuel quality, cold/warm) . . . so I'm just as curious about this as you. I've been considering taking it to service, but since the problem is so intermittent it would be hard to 'prove' the problem to the service personell . . .

It is a slight hesitation for a second on my car but then it kicks in, and it's too early to be the DSC, I know the difference from having the DSC kick in while accelerating and the experience is different.
 
me too, me too ... i especially notice it when going from 1st to 2nd, when hitting the throttle hard
 
taffy said:
yes I get some too, use Vpower or Tescos99

So I do, and even used 100 octane down on the continent (Germany/Italy), but it does not seem to be related unfortunately.
 
is it the same thing i get.. at very low revs in second gear (cruising in traffic) then you hit full throttle and it briefly surges to go, then hesitates (almost misfires), then screams off..

I get this fairly regularly... =S
 
Andy said:
is it the same thing i get.. at very low revs in second gear (cruising in traffic) then you hit full throttle and it briefly surges to go, then hesitates (almost misfires), then screams off..

I get this fairly regularly... =S

I had an issue with the 3L - Air mass flow problem, a new one sorted out the hesitation.
 
It may be completely unrelated, but I had that on my old Audi A3 and it was the fuel pump starting to give up. The fuel-pump was overheating and as a safety measure the ECU would either limit fuel supply to the engine or in more extreme cases would cut off the fuel supply completely.
 
I experienced this around 1 month ago with my 53 plate Z4 3.0. It was as if there was a lag with both reponse and power and it seemed as if full power was not being obtained. Then the car would not start and it turned out to be the fuel pump which had completely died. Be warned, an expensive bill potentially from your BMW dealer.
 
me too, me too ... i especially notice it when going from 1st to 2nd, when hitting the throttle hard

Yep that's it - its first to second when it can really hesitate - i did wonder as it seems to do it more when the fuel tank is under half full if the fuel was moving away from the pickup and fuel pressure was temporarily dropping. Its going to visit the dealer very soon as my oil level gauge seems to show different readings every day :roll:

I'll let you know what the dealer has to say

Cheers

James
 
thx James, let us know is that is the issue ... i tried to different ways of driving (ie. hard vs not and everything in between) and when driving like a tame driver, where i accelerate like the rest of the world and shift at about 3-4k rpm, no issues

when i pin the throttle in 1st up to 6k and then shift hard to 2nd, i notice the the delayed throttle response, almost like turbo lag. could it be that the engine sucked out all the air from the airbox and is waiting for it to refill?? i mean, you are still going kinda slow at the end of 1st gear, so maybe the air hasn't been replaced yet by new air coming in from the kidney grills. i know that makes NO SENSE at all since there is always air around us, but i'm just trying to come up with some reason :P

coupe-sport said:
me too, me too ... i especially notice it when going from 1st to 2nd, when hitting the throttle hard

Yep that's it - its first to second when it can really hesitate - i did wonder as it seems to do it more when the fuel tank is under half full if the fuel was moving away from the pickup and fuel pressure was temporarily dropping. Its going to visit the dealer very soon as my oil level gauge seems to show different readings every day :roll:

I'll let you know what the dealer has to say

Cheers

James
 
Are people experiencing this on Ms, or on the other models? I can't say I've had this issue on mine, and it gets quite a few full-bore acceleration runs...
 
sixspeed, I got it on my M . . . but now it has been like two weeks since last time.
Just delivered the car to first oil service and asked them to have a look at it. They will probably say they have not been able to reproduce the problem, but you never know.
 
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