Loss of boost when hot

Spuddog · Post by **Spuddog** » 29 Jun 2016, 14:54

I'm starting to think it might be my TCV, not sure why its only affected when hot but I have ordered a Manual Boost Control Valve to have a play with only £12 so a cheap fix if it works, I may even treat it to a proper TCV if it works. I will update in a few days once it arrives and I've fitted it

Spuddog · Post by **Spuddog** » 20 Jul 2016, 03:46

That didn't sort it improved boost when cold but still looses power when up to temperature, don't know what the solution is now any help appreciated

jamestas · Post by **jamestas** » 02 Feb 2025, 05:32

Did you resolve this in the end?

yanga001 · Post by **yanga001** » 05 Feb 2025, 07:57

So Volvo uses the TD04 HL turbo which is actually used in a wide range of vehicles. I have seen a lot more turbo issues on Acura's that utilize this design, and it is usually due to bad wastegates, blown air lines, or bad seals. These turbos are fairly robust so i would say your first bet is to use Vida or some sort of scan tool and measure airflow, boost, fuel pressure, etc while doing some runs. Turbos balance a lot of different parameters during operation so any one parameter can throw it out of balance.

One thing i learned from the Acura forum is lazy diagnostics can cost you a lot. The Honda manual calls for turbo replacement far more often then it really should. I've noticed that the volvo forum has been a bit more resistive to parts cannon approaches.

Anyways, get the data and let us know what it says. Lost boost/0 boost is different from low performance, overboosting, etc.

Post by **jonesg** » 06 Feb 2025, 22:27

Yank on the rubber coupler pipe from the turbo to the charged air pipe, they get soft and can easily blow off under pressure, then you let off the gas and it gets sucked back into place and looks completely normal.