Hi, just after a bit of advice from the people who know.

I've left a deposit on a ST205 GT4 (1995), will be picking the car up on Wednesday this week. However, the current owner, who hasn't had the car long, said that when he bought the car it was overboosting. The diagnosis from a local Subaru specialist was that the manual boost controller was malfunctioning, so the boost controller was removed and the pipes were joined together.

The car runs faultlessly (or did on the day), so I was wondering if this bypass would then engage the ECU or EBV (if one is fitted)? Or do you think that I should replace the manual boost controler as soon as possible - would this cause problems further down the line if I left as-is?

Many thanks
Steve

With the manual boost controller disconnected/disengaged and the pipes joined together (properly) then the boost is controlled by the ECU - which will be absolutely fine.

You may wont to consider an electronic boost controller at a later date.
I personally would go for an HKS EVC or Greddy Profec B Spec II...but there are others out there that are good.

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Thanks Muddy Water, that's exactly what I needed to know. I'll certainly be looking into one of the electronic versions later in the year.

Much appreciated
Steve

There is the possibility that when the manual boost controller was installed, the built in TVSV was disabled, which will remove ECU control. Without the MBC, it will just run actuator boost (about 0.5bar from memory).
This is normally done by cutting the pipe on the rear port of the actuator and blocking both ends, although it can also be done by unplugging the electrical connection to the solenoid itself (located under the inlet manifold)

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Good point Chris.
My original comment:

To clarify, check this pic out:

Courtesy of GTFours.co.uk
That shows the TVSV disabled (see the 2 phillips head screws in the pipes) - you need to ensure that these 2 pipes are unblocked and connected back together again.
Then the ECU will control the boost.

_________________
Vice Chairman
1990 White UK Celica ST185 - Project DTM
1997 Cream BMW R1200C (as seen in James Bond "Tomorrow Never Dies")
2005 Jaguar X-type 3.0 Sovereign AWD Automatic
Blood Bikes - https://www.freewheelers.org.uk/