[Mustard3]

I've been trying to figure this one out for a couple of months now. I haven't been able to find a similar problem on an internet search of the 335d or 535d various 'power loss' issues.

On part throttle openings the car seems to run normally, by that I mean pick up is smooth and even right across the rev range, and with the force you would expect. But with wide open throttle (foot to the floor) the power feels 'reigned in', and holds back most noticeably at higher revs - where there is sometimes a barely noticeable hesitation and it will sometimes change up at 4,300 revs even with the foot pinned.

There are no fault codes.

I have replaced MAP & inlet charge pipe sensors, replaced engine breather, cleaned MAF, new air filter, fuel filter replaced 20k miles ago, red intercooler pipe fairly new and in good order, vac pipes appear okay, BP ultimate.

I have an Evolve Switch and have tried running the car in standard and modified maps, the problem is present in standard and more pronounced in modified, but I don't think the map is at fault, rather some mechanical, fuel or vacuum problem that is not coping with the demands of WOT.

Any suggestion gratefully received, thanks.

[garytc78]

I'm no expert on this but could it be something to do with the turbo actuators?
Sort of sounds like they could be opening on part boost but not working up to full boost possibly?

[swhoyle]

Im sorry I can t offer you any advice, however I did see the below post on here a short time ago ... sounded similar to yours - apologies if this is not the same issue


http://www.e90post.com/forums/showthread.php?t=637603

[AlwynMike]

If the car is changing up at 4300, then I would tend to be looking at the gearbox software - maybe it's sensing too much torque and limiting the engine in the manner you describe. In Sport, the car should change up at redline whatever, when you are pedal to the metal. Another thought that has just occurred is the throttle positioner (on the accelerator pedal) - maybe that has a fault at the fully open end, and is effectively closing the throttle for you, hence changing up early and limiting your power delivery.

Of course, I'm only guessing, and I could be talking garbage!

I'd actually like mine to change up at 4300 when pressing on - anything more is just revs - it's quicker changing up than hanging on.

Mike

[Mustard3]

Thanks for the ideas.

Originally Posted by garytc78

I'm no expert on this but could it be something to do with the turbo actuators?
Sort of sounds like they could be opening on part boost but not working up to full boost possibly?

A good possibility, I don't know at what point they'll give a fault code.

Originally Posted by swhoyle

Im sorry I can t offer you any advice, however I did see the below post on here a short time ago ... sounded similar to yours - apologies if this is not the same issue


http://www.e90post.com/forums/showthread.php?t=637603

This problem seems to be quite common, losing power at low revs and is usually caused by a faulty pressure converter. My problem is at high revs though, could be the other pressure converter I suppose.

Originally Posted by AlwynMike

If the car is changing up at 4300, then I would tend to be looking at the gearbox software - maybe it's sensing too much torque and limiting the engine in the manner you describe. In Sport, the car should change up at redline whatever, when you are pedal to the metal. Another thought that has just occurred is the throttle positioner (on the accelerator pedal) - maybe that has a fault at the fully open end, and is effectively closing the throttle for you, hence changing up early and limiting your power delivery.

Of course, I'm only guessing, and I could be talking garbage!

I'd actually like mine to change up at 4300 when pressing on - anything more is just revs - it's quicker changing up than hanging on.

Mike

The low up changes are happening in manual mode?! Problem has gotten worse since yesterday. I have it booked in next week with a specialist.

[raf555]

Could be a faulty 'throttle valve actuator'?