Throttle / Engine problem

[RAW]

Hi Guys,

Having a few problems with my Z4M...

Its a 56 with only 16000 miles and I picked it up about 3 months ago, but its been in to the dealers 3 times now with missfiring / throttle problems.

First time - Obvious miss fire at around 4-5k revs, very loud backfire when coming off the throttle and then back on again. Fixed by updating the ingnition / cpu map.

Second time - Engine light came on - Fixed by replacing both oxygen sensors.

Now its back at the dealers again - When the throttle pedal is pressed the revs die slightly before rising. Its not a massive problem but it makes pulling away from standstill a bit tricky, as if I dont rev it slightly before I pull away the engine dies and makes it look like I got the clutch wrong. Everything else seems fine, it pulls well through all revs, no missfires, no other problems. But when I come off the throttle and then back on again, it dies for just a second before reving.

This problem has been there all along. Each time Ive taken it in Ive mentioned it but its not been fixed despite the work they have done. Its been at the dealers almost a week now and not a great deal seems to be happening as they fully admint they dont know what the problem is. They have suggested today that its a characteristic of the car, which worries me a little as its a bit of a pain in the arse to drive with this problem.

Does anyone have any ideas about this and is it realy a characteristic of the car? - I drove 3 others before this one and dont recall any of them doing this?


Rich


1st post from a brand shiny new member, so go easy plz

 

[sammyz]

Welcome to the Forum! Sorry to hear you're having problems.

Ideally you need to compare your car with another 'M' to see if there is a noticable difference. has the dealer got one?

I wouldn't accept that the problem you have is a 'characteristic' of the car at all! Sounds like the dealer trying to get out of a repair! The sensor problem seems quite common but other than that not too many problems around throttle response. The car can be tricky when pulling away but from what you say the problem sounds to be stopping you driving the car smoothly so it is a fault and the dealer needs to sort it out.

 

[Raify]

Where are you? Perhaps a forum member nearby could compare cars?

 

[Andy]

Welcome ! I've got a 06 plate with 34k now that I've experienced both the first two, but never the third.

Let us know where you are and someone might be able to give you a demo.. I'm in Warwickshire.

 

[chetalien]

Interesting because I seem to get the same problem and feels that the fuel is being cut off and suddenly springs to life(like a splutter). Couple of times when i depress the clutch the ignition turns off whihc is difficult if i'm truning in coz i'm stuck. Thought i wasnt depressing clutch properly or I wasnt using the throttle appropriately. I will whizz it to the dealers asap. still got 3 months warranty on it.

 

[RAW]

Im in Wolverhampton if anyone is nearby

The dealer does have another M there and has tried swapping some parts onto my car. At least that is what they have said, although they seem to change the story of exactly what they have and havent done, depending to the time of day, alignment of the stars etc...

Its been there a week now and its begining to get anoying as it seems that nothing is happening. Even the crappy 118d loan car they have given me doesnt exhibit this "characteristc" :x

 

[sammyz]

I'd ask the dealer to let you drive the other 'M'. If that feels the same to you then face it- your a crap driver

Far more likely - on the other hand, if the car drives as I would expect then you can tell them that your own car has a fault and needs sorting!

 

[Andy]

I'm about 40 miles away, if you fancy a trip !

If someone else has it though, it may help.. but im pretty sure mine doesnt

 

[etedlm]

iv'e posted on the engine management thread about what the dealer did to my car as i had the very same problem with the trottle at low rpm,sorted now.i also change the grade of fuel to super unleaded and that also played a part in curing the problem

 

[RAW]

Thanks for the help guys.

I had a bit of shout at the dealer yesterday and they seem to actualy be doing something today. They have swapped a number of parts from their Z4M onto mine (coil packs, plugs, CPU) and still havent found exactly what the problem is. I didnt get chance to call them late on today for an update, so ill see if they have any progress in the morning.

Andy, will have to arrange a trip out when (if) my car is fixed

etedlm, I read through the engine management thread and Im not sure we have quite the same problem. Mine dies slightly on appliaction of the throttle which makes pulling away a pain, but it also does it at higher revs. If I back off the throttle and then re-apply at say 2k revs I can feel it hesitate for a second before accelerating. The higher the revs the less obvious the hesitation is, but its definatley still there.

The dealer has checked the "Puma"? system, contacted other dealers and contacted BWM directly and so far they say this is the first reported case of this type

Has anyone else ever come across this, or am I just special?

 

[ian in lancs]

mine doesn't have this hesitation. For info the Puma system is a database of faults.

 

[daz05]

Could it be your ECU isn't working, a friend of mine had something similar on an old E36 and had it replaced. Fixed after that.

 

[Phoenix]

I have some hesitation occasionally when pulling away or when accelerating from very low revs (say a junction where i havent quite stopped). It also feels to me like its fuel starvation. I thought maybe i was bringing up the clutch too quickly... was gonna get em to look at it when i get my next service tbh.

Let us all know how it goes.

 

[RAW]

Well Ive finaly got the car back now. :yeah:

Was at the dealers for just over a week, they still dont know whats wrong and say its still not fixed. It has been booked to go back in again when one of the main technical guys is visiting next month.

They havent said exactly what they have done, but the car does seem a lot better now and only shows the problem occasionaly. Ill still take it along for the tech guy to look at but unless it returns to how it was before, I would class it as fixed now