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Hesitation when accelerating ?

Discuss problems you have had or are having with your Z4
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coupe-sport
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Hesitation when accelerating ?

Post by coupe-sport » Fri Aug 17, 2007 10:52 pm

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
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Wondermike
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Post by Wondermike » Fri Aug 17, 2007 11:03 pm

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?

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Post by sixspeed » Sat Aug 18, 2007 3:31 am

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...

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Post by coupe-sport » Sat Aug 18, 2007 8:09 am

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
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sixspeed
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Post by sixspeed » Sat Aug 18, 2007 11:53 am

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....

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Post by Andy » Sat Aug 18, 2007 2:09 pm

sixspeed wrote: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..

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Post by coupe-sport » Mon Aug 27, 2007 8:07 am

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
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Post by Color » Mon Aug 27, 2007 9:08 am

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.

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Post by E85 » Wed Aug 29, 2007 3:35 pm

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

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Post by taffy » Thu Aug 30, 2007 1:34 pm

yes I get some too, use Vpower or Tescos99

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Post by Color » Thu Aug 30, 2007 1:47 pm

taffy wrote: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.

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Post by Andy » Thu Aug 30, 2007 2:19 pm

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

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Post by pop_sausage » Thu Aug 30, 2007 3:05 pm

Andy wrote: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.

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Post by tehdarkstar » Thu Aug 30, 2007 3:18 pm

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.
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eddieo

Post by eddieo » Thu Aug 30, 2007 4:29 pm

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.

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