I have been doing some further research as I am having similar problems as above. To me between 1850-2750 revs there does not seem to be the sharp pull (pinning to the seat) as before when I bought the car. Once I hit past the 3k rev mark and the big turbo kicks in thats when I know things are moving.
I have changed the red boost pipes, along with the seals. Also the seals on the other side of the pipe which goes back to the inlet manifold. I have checked vacuum hoses the best I can, changed the oil breather pipe to help the engine breathe if the other other one was blocked.
I seem to get the above intermietantly, when it has goine into a dealer nothing has been picked up and made me look like a right idiot. Next on my list is the pressure convertors. But before I put my order in the for the pair I decided to plug in my INPA and the only code came up was 41AA - looking this up on google seems to suggest a Boost pressure sensor. Then I was reading this in the 5 series section on another forum which got me thinking maybe the boost pressure sensor is at fault and going to replace this before looking at changing the pressure convertors.
http://www.bimmerforums.co.uk/forum/...-cured-t82595/
Quote:
My 320d has now gone and I’ve bought a 2006 (registered early 07) E61 520d. This has the M47TU2d20 engine (161 or 163bhp).
Not long after buying it, it developed a really annoying, intermittent and ever-changing fault.
1. It was terrible from low-revs. Even in neutral, it was very slow to respond to throttle, and in-gear it was bloody dangerous. Sometimes I had to ride the clutch up to 2000rpm and I couldn’t pull away up hill!
2. No matter what the engine speed, there was a crazy lag between throttle and response. Like I was driving a car with a huge turbo with bad lag.
3. Sometimes it wouldn’t come on boost until 2200rpm (my 320d was strong from 1600rpm).
4. Sometimes, when on boost, it would hesitate as the revs climbed – rather like a mis-fire or flat spot.
5. Sometimes, it would not rev past 3750rpm.
6. Sometimes, the turbo would make a (non-load, non-engine speed related) escaping gas noise.
7. Sometimes, it was just fine!
My initial thoughts were MAF, EGR valve and expensive turbo problems! A basic (non BMW) diagnostic showed nothing.
After weeks or checks, elimination and research I have finally cured it. This is what I did.
1. Visual check of all boost pipes and vacuum hoses. All fine.
2. Swapped MAF with identical and known good MAF from wife’s car. No change.
3. 2 doses of ‘Forte’ and 600 miles of very hard driving (under 28mpg average!) This resulted in several successful regens of the DPF. No change.
4. Disconnect EGR vacuum pipe and blank off the pipe with an 8mm bolt (so that the ECU still detects a load on the vacuum pipe). This resulted in a yellow emissions warning on iDrive which vanished 2 days after reconnecting. Overall – no change.
5. Remove, clean and check operation of EGR valve. No change.
6. Check operation of turbo actuator arm. I did this by watching it while my wife revved the car. The actuator moved, but not as much as expected and seemed unrelated to throttle position. (£££worry!)
7. Check air filter element. Fine (5 months and 6k miles old), but given a thorough clean. No change.
8. Remove and clean MAP sensor (by bathing in petrol). Refit. Significant difference!!! All problems improved but throttle response now very ‘on/off’. Still intermittent power loss under acceleration.
9. Replace MAP sensor (part number 7 787 142. £70 from BMW). All issues now cured.
The MAP sensor (manifold absolute pressure) sensor detects the pressure (boost) in the manifold which the ECU compares to the volume of air passing the MAF. Boost is adjusted dependent on this pressure by the turbo actuator and fuel supply. A faulty MAP sensor will play havoc with your boost and may give symptoms similar to a duff MAF, turbo or EGR valve – all of which cost much more than £70!
You need a small mirror, a spanner, 20 minutes and dexterity to change your MAP sensor – nothing else. It would be more difficult on a 3 series as the manifold is further back under the lip of the bulkhead.
I can and will add a few photos of the location of the MAP if anyone is interested.
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If someone can tell me where this is located on the 335D engine I can take it out give it a clean and check before I order a new one