320d intermittent power loss

08-320d · 07-12-2021, 06:49 PM

2008 E90 320d N47 automatic with 115k miles.

I've being having issues with my 320d the last few months. Always suspected it was down on power though I get the odd bit of normal power the odd time. The other identical 320d we have in the house drives much better and has about 50k miles more.

Anyways I had the car on the dyno and it only put out 147hp, down about 30bhp. I'll attach the print out sheet below.

Tuner reckoned it was the turbo actuator. When I got home I scanned for codes and everything came back fine.

Brought it to my BMW specialist a couple of weeks later and he had done a diagnostic on it including the actuator test and said he can't find anything but sees that the car is not boosting correctly from driving it. Suggested a new turbo but couldn't promise it would fix it. My turbo has none of the typical failure symptoms.

Ive since then blanked the egr (was mapped out already), changed map and maf sensor. Not much improvement. Its swirl flaps and dpf have also being removed.

Also had a boost leak test done in another garage and no leaks. They were also none the wiser what was up with it.

I find the odd occasion (usually from cold/first start up) that the car will drive perfect with good low down boost. When I returned from holidays it drove great for about 4 days and went back to it's dodgy ways. It also drove perfect when going to work this morning. Clogged vanes ??? But no fault code

If anyone had any opinions please share away as it has my head wrecked 😭

J21J · 07-23-2021, 12:30 PM

Its sounds like a possible boost leak. It can be a nightmare to track a leak down so it's possible the leak has been missed.

Can you get data for the injector correction values/smooth running?

07-12-2021, 06:49 PM	#1
08-320d New Member 8 Rep 28 Posts Drives: 320d e90 Join Date: Jun 2020 Location: Ireland iTrader: (0)	320d intermittent power loss 2008 E90 320d N47 automatic with 115k miles. I've being having issues with my 320d the last few months. Always suspected it was down on power though I get the odd bit of normal power the odd time. The other identical 320d we have in the house drives much better and has about 50k miles more. Anyways I had the car on the dyno and it only put out 147hp, down about 30bhp. I'll attach the print out sheet below. Tuner reckoned it was the turbo actuator. When I got home I scanned for codes and everything came back fine. Brought it to my BMW specialist a couple of weeks later and he had done a diagnostic on it including the actuator test and said he can't find anything but sees that the car is not boosting correctly from driving it. Suggested a new turbo but couldn't promise it would fix it. My turbo has none of the typical failure symptoms. Ive since then blanked the egr (was mapped out already), changed map and maf sensor. Not much improvement. Its swirl flaps and dpf have also being removed. Also had a boost leak test done in another garage and no leaks. They were also none the wiser what was up with it. I find the odd occasion (usually from cold/first start up) that the car will drive perfect with good low down boost. When I returned from holidays it drove great for about 4 days and went back to it's dodgy ways. It also drove perfect when going to work this morning. Clogged vanes ??? But no fault code If anyone had any opinions please share away as it has my head wrecked 😭 Attached Images
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07-23-2021, 12:30 PM	#2
J21J Enlisted Member 3 Rep 32 Posts Drives: Bmw E90 Join Date: Jul 2021 Location: Scotland iTrader: (0)	Its sounds like a possible boost leak. It can be a nightmare to track a leak down so it's possible the leak has been missed. Can you get data for the injector correction values/smooth running?
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