e90 320d strange power / turbo behaviour

[timwatsham]

Another 320d power problem, but different to all the others I can see on the forum...

I've an E90 320d touring, 55 plate just gone over 110k on the clock and frankly a brilliant car. Just had my best brim to brim with 52.5mpg, and it is great to drive. However, I have an intermittent problem that first started 13k ago and is starting to annoy me.

Normal driving day to day everything is perfect. BUT... If I accelerate briskly (not hard, just going up to say 3,000 rpm) before the engine is fully warmed up, then the turbo refuses to kick in on subsequent acceleration until I reach 2,700rpm - after that its all fine. NB - I know its the turbo not coming in as the whilstling with the window open isn't there.

Really annoying trait, and to be honest one that I've put up with for a while, but I've just changed offices and now need to accelerate up a slip road onto the A1m after a mile or so of leaving work, and only using 2,200rpm is becomming tedious.

Anyone got a clue? Feels like something in the ECU, but nothing I've heard of before...

Grateful for any ideas. Oh, and last serviced 5,000 miles ago for an oil change - didn't kick out fault codes...

[phumy]

You say this problem only happens when the engine is not up to temperature, is it ok once it has reached normal?

[caduceus]

Did it happen after a service by any chance? Not the last one, obviously. The one before.

[timwatsham]

When its warm before being brisk acceleration, all is fine. Most of the time it doesn't happen, its just late evenings when I need/want to accelerate more quickly up the slip road or if you've stopped in a motorway services for a while to let it cool down and then accelerate to join the motorway.

And no, not after the service. Previous service was 83k and I didn't notice the problem until 97k...

Strange isn't it?