Volvo Owners Club Forum - View Single Post - S40 (New) Engine 2.0D :

Sidonas · Aug 8th, 2020, 20:29

I think I have found an issue with the car but I'm not sure what could be the cause of it. While graphing the desired and actual boost values during a pedal to the metal run I've noticed that pretty much every time the car manages to boost to the desired value, it overboosts (actual value goes above desired). It then goes into some sort of fail-safe and lowers the boost pressure. After this happens, it does not boost back up to the desired value. I am suspecting a faulty TCV but it is fairly expensive to just replace it, so I'm looking for a second opinion.

The first graph also shows whatever the TCV is doing during a similar run but I find it hard to interpret.

Graph:
https://imgur.com/a/LcDQUa3

Aug 8th, 2020, 20:29	#2
Sidonas Junior Member Last Online: Aug 28th, 2023 13:55 Join Date: Oct 2019 Location: Kaunas	I think I have found an issue with the car but I'm not sure what could be the cause of it. While graphing the desired and actual boost values during a pedal to the metal run I've noticed that pretty much every time the car manages to boost to the desired value, it overboosts (actual value goes above desired). It then goes into some sort of fail-safe and lowers the boost pressure. After this happens, it does not boost back up to the desired value. I am suspecting a faulty TCV but it is fairly expensive to just replace it, so I'm looking for a second opinion. The first graph also shows whatever the TCV is doing during a similar run but I find it hard to interpret. Graph: https://imgur.com/a/LcDQUa3 Last edited by Sidonas; Aug 8th, 2020 at 20:36.