Turbo Lag and low MPG XC90 D5 Powerpulse

[Draig]

I have a 2016 D5 Powerpulse XC90 which I had been very happy with performance and efficiency up until I had a problem with the Boost pipe / powerpulse a couple of years ago. This was sorted under warranty but the car didn't quite drive the same, and seemed to still lack power at times with what felt like a turbo lag. Since then has been back and looked at a few times with boost pipe failed 3 times (volvo claim not a cause for concern). It also had what I think was an issue with swirl flap fixed when I continued complaining about the lack of improvement(they were a little vague on this)

Athough they claim to find nothing specific beyon these issues and that it is fixed I am still not convinced and still feel there are issues with
• Hesitation / Lag in power on acceleration and lacks smoothness
o Initial lag followed by a partial burst of power and then a sudden jump in revs with further boost
• Often runs high revs even with gentle acceleration
• Occasional epsiodes of revs sticking at ~3000rpm even after releasing accelerator
• MPG dropped from 33-34MPG average to <30MPG since problems

Volvo keep saying there is nothing up and I am starting to think it is all in my mind, but every so often I get a short period of normality that reminds me of what I used to get.

Anyone had similar issues or any thoughts

[Dulcise]

The swirl flap is normally part of the intake manifold, so unless the dealer has changed this it could still be causing your issue. This is an easy DIY job normally, but I'm not sure of cost of a new one...may not be that expensive. If it's still under warranty the dealer should be able to diagnose and change.

[Deman77]

What you are describing sounds a lot like gearbox logic. Powerpulse should only be impacting things at lower revs.

Long shot but try this as it is free. Try resetting the gearbox logic. Put it in off road mode then accelerate past 30mph so it will move back to comfort. That resets the learnt gearbox adaptive programme. If you do not have mode selector then it will need to be full software upgrade. That should happen on every main dealer service but dealers are known to skip this step as it is very long.

Could try changing oil in gearbox - if your usage is low speed with lots of cold starts chances are it is a mess by now. Dealer would refuse but there are many indis who swear by changing gearbox oil in boxes “sealed for life”.