09 V70 2.4D Euro 4 - Boost control issues

[foggyjames]

Interesting - my D4 (but nominally the same thing) definitely has two pressure sensors, and a stepper motor for the VNT control! If it really does have vacuum controlled boost, look for the filter on the solenoid (to let air back in, to limit boost!). Euro 3 techniques will apply.

The 2.4D in the P2 and P3 are nominally identical, although there are a few differences (pipework, etc). I would expect the boost pressure to be the same.

cheers

James

[Black dog]

Originally Posted by foggyjames

Interesting - my D4 (but nominally the same thing) definitely has two pressure sensors, and a stepper motor for the VNT control! If it really does have vacuum controlled boost, look for the filter on the solenoid (to let air back in, to limit boost!). Euro 3 techniques will apply.

The 2.4D in the P2 and P3 are nominally identical, although there are a few differences (pipework, etc). I would expect the boost pressure to be the same.

cheers

James

Yeah my 2006 2.4d has the stepper control turbo yet the d3 is vac solenoid with an electronic position sensor on the rod. Filter is clear, mine seems to be more ecu related (requested too high)

[foggyjames]

Little update - diagnosis complete, but yet to be fully rectified. Credit to Clayton's of Mansfield (authorised service centre) for most of it.
Three issues, in the end:
1) VNT vanes seized (contemplating a new turbo, given that it has done 227K)
2) Boost leaks - rocker cover gasket and/or the seal on the end of the swirl flap rod - neither of which had occurred to me.
3) It did indeed have a remap, possibly of questionable quality, which was exacerbating the issues.

The remap has been removed via a full software update, and the car is now much happier. It's possible to drive it at full throttle without ill-effects provided you keep revs below 2500 (maybe 3000 if you're feeling keen). I will fix the boost leaks first (because they're easier), and continue to ponder replacement turbo vs un-sticking of the vanes. Given the weather, the turbo job can wait...!

cheers

James

[foggyjames]

I received a PM about this thread, and thought I should post an update.

I replaced the rocker cover gasket and swirl flap rod (and hence seal), but that didn't do the job. Further inspection of the turbo revealed that the issue was not, in fact, seized VNT vanes (they moved freely), but a failed VNT motor. That was replaced with a used unit, as genuine ones don't appear to be available separately to the turbo, and I didn't want to trust an aftermarket unit (given their price).

The car is now 95% fixed. There's still a bit more lag than I would expect, which I think is probably due to the VNT motor not being quite calibrated correctly to the the turbo. There is a software calibration, but I think you can always make a hardware adjustment...but I don't know what's involved in that. It's "good enough" now, certainly.

cheers

James