2001 V70T5: little to no boost...how do you know when TCV is

carboncow · Post by **carboncow** » 05 May 2015, 20:39

Bad?

No codes on Vida Dice or OBD2 reader. Recently cleaned VVT (and new gasket) to fix issues with erratic power and idle. It's happy for now...no codes but still little to no boost out of a T5

Cannot find any leaks, idle is solid.

Where next?

Post by **abscate** » 11 May 2015, 09:28

Probably try disconnecting and plugging the boost hose from the TCV to see if anything changes

Other than looking at the drive signal to the TCV with an oscilloscope or hooking up a boost gauge. it's pretty hard to diagnose TCV .

I believe there are many inputs into the ECU which will inhibit boost or reduce it

carboncow · Post by **carboncow** » 11 May 2015, 12:34

Thanks. I did have the TCV off to make sure the unit was clean as well as the hoses to each location.

Are you suggesting by passing the unit and direct connecting two hoses together to simulate the TCV engaging? If so which two hoses?

I can pull the TCV off another car if needed and swap out.

I would assume that any of the other inputs that would inhibit boost would show up on Vida/Dice with some type of code, no? Disconnecting the TCV does in fact trigger a code.

The ONLY code I have currently showing up in the O2 sensor on top of the cat. This issue has been there for years and the boost issue is relativity newer.

Thanks.