T5R boost question / help please

[Pupbelly]

Looks like it was overdue to do the expansion tank!

[s1monc]

Looks like you replaced that just in time!

[Pupbelly]

Today I’ve done further research on my low boost issue. I’m running Cataclean through the system just incase there’s a blocked exhaust issue, I don’t think there is but just in case.
Anyway I read that disconnecting the yellow wastegate line to the boost control valve should create a huge swathe of boost….so I disconnected it and did a trial (gentle) run. Nothing. Bugger all just the usual barely into the white boost.

So does this point towards a duff actuator? The forum I was reading in the states then cured this by replacing the actuator, is this correct for all cases?

I’m sending the car in to my Subaru guy next week so I guess he’ll be able to pressurise the wastegate to establish if it’s working or not. I understand the T5R runs the same turbo as the Impreza TD04 so maybe my guy may have an actuator that will be swappable?

Amended to state actuator not wastegate

[Baffler]

The WG is integral to the turbine (hot side) housing. I wonder has the WG somehow jammed in the open position? With the engine cold disconnect the vacuum line to the WG actuator and see if you push/pull the actuator arm.

To see parts and images search for Volvo TD04 (Mitsubishi family of turbos) on Kinugawa.

[Pupbelly]

Originally Posted by Baffler

The WG is integral to the turbine (hot side) housing. I wonder has the WG somehow jammed in the open position? With the engine cold disconnect the vacuum line to the WG actuator and see if you push/pull the actuator arm.

To see parts and images search for Volvo TD04 (Mitsubishi family of turbos) on Kinugawa.

I’ve tried moving the actuator shaft and it does move. There’s a lot of resistance against the spring but it does move. I’m not sure what a certain PSI relates to so far as being able to move the shaft/rod but there’s definitely a very firm pull required to make it move.

[Pupbelly]

Apologies I use the term wastegate but I mean actuator. I’m thinking the actuator is duff hence no movement to the wastegate.

[Pupbelly]

Anyone got any thoughts or input?

[s1monc]

I’d try shortening the actuator arm just to see if that makes any difference at all.

[Baffler]

Originally Posted by s1monc

I’d try shortening the actuator arm just to see if that makes any difference at all.

Or maybe it has been shortened too much already causing it to hold the WG open?

@ Pupbelly...if you remove the little clip pin from WG lever, gently lift off the actuator arm, you should now be able to open/close the WG freely with your fingers. Prior to removing the actuator arm, note the WG position, and then see if it has far to travel from the actuator arm to be in the closed position. If needs be adjust the actuator end lug accordingly (anticlockwise) but you'll need a proper boost gauge fitted to monitor boost under load and make fine adjustments.

Tip: undo the end lug locking nut prior to removing the arm and try not apply too much pressure to the actuator diaphragm when moving the arm off and on.

[Pupbelly]

Baffler, I was going to have a fiddle with the actuator but without a proper boost gauge I didn’t want to create more issues. It also meant taking the turbo heat shield off which I also didn’t want to shear any bolts.

The car is booked in this coming Friday with my Subaru guy. He’s going to give it a check over and hopefully blitz this issue. Needless to say he’s got all the correct kit and knows the TD04 type turbos with his Subaru knowledge.

In theory all the usual areas have been checked i.e.

Vacuum lines replaced with new silicone
New turbo control solenoid
New throttle position sensor
All intercooler hoses removed and checked and cleaned.
Cataclean currently being run through the system

After removing the wastegate (yellow) hose and driving and get no difference in boost it seems to point to an actuator issue or wastegate query. Hope to goodness Mr Subaru sorts it. I want some shove back in the seat surge!