T5 no boost

Hey guys

I've just purchased a 2004 s60 T5 and noticed when I was driving it felt quite low on boost so I decided to install a boost gauge which is telling me I’m only get maximum of 4psi. I’ve check the wastegate, hoses for leaks, bypassed the boost pressure sensor and still minimal boost. I’m new to these cars so it’s tickling my brain. Any help of advise would be greatly appreciated.



  • The wastegate is a 4psi wastegate

    Sounds like the electronic boost solenoid has failed ( somewhat common) ipdusa.com sell a nice upgrade unit as a kit

  • Rbs60Ryan @Rbs60 Goulburn nsw

    Oh ok so there set at 4 psi standard?

  • Yeah @Philia_Bear is right it's more than likely your turbo control solenoid (lives on the side of the airbox with 3 vacuum lines)

  • Rbs60Ryan @Rbs60 Goulburn nsw

    so that would cause no boost at times and up-to 4psi other times?

  • Rbs60Ryan @Rbs60 Goulburn nsw

    Also if I upgrade the wastegate to effectively allow more boost would that work or is there more things necessary to achieve more?

  • Basically Ecu sees boost from the pressure sensor, ecu uses turbo control valve to reach target boost pressure.

    Unless you tune the ecu (me7) then you can't really adjust the peak boost, but you should be seeing more than 4psi

    Turbo control valve is a simple solenoid opening and closing at high frequency. They usually stick/jam up randomly. So is usually the cause of any intermittent boost issues.

    Do you have the ability to read fault codes or see live ecu data?

  • Rbs60Ryan @Rbs60 Goulburn nsw

    oh ok that makes sense. I do have a mate with a shop and a scan tool if that would work for codes of data?

  • Rbs60Ryan @Rbs60 Goulburn nsw

    Or data

  • 04 s60 you can read live data and see what the ecu sees

    not all scan tools will work on volvo so cant advise if your mates will or wont work

  • Rbs60Ryan @Rbs60 Goulburn nsw

    Hey guys

    so I picked up a second hand boost solenoid today just to see if that’s the issue and still the same problem! Only reading 0-1psi on boost gauge even under load😡

    any other ideas?

  • Basic checks

    #1 Pull the intake pipe off the front of the turbo and make sure it spins....

    #2 Second hand solenoid could be bad or could be a wiring issue

    #3 Checked the turbo to intercooler and intercooler to intake for blown hoses?

    #4 have you tested the boost gauge to ensure it does read boost? where are you pulling your reading from?

  • Rbs60Ryan @Rbs60 Goulburn nsw

    I have checked the cold side of the turbo and spins freely with no shaft play.

    Ive checked the intake crossover pipe and all seems fine.

    havent really checked the cooler to manifold pipe as it looks quite difficult to get the pipe off the underside of inlet manifold but I haven’t had a very close inspection.

    We have listened for boost leaks under load and cannot hear anything and the boost gauge was working fine in the last vehicle it was in and it’s a good quality one.

    maybe it’s the intercooler leaking somewhere or could it be the PCV system?

  • Unlikely to be pcv, could be the compressor bypass valve.

  • Rbs60Ryan @Rbs60 Goulburn nsw

    That’s on the turbo itself isn’t it?

  • Yeah it's 3 bolts and you can make a block off plate to test if its the issue. The diaphragm can split

  • Rbs60Ryan @Rbs60 Goulburn nsw

    What would happen if I left the block off plate in there?

  • Same effect as blocking off a bov on a JDM car - turbo flutter.

  • Rbs60Ryan @Rbs60 Goulburn nsw

    Ok thanks Tim I’ll give that a go and see if I can get some boost pressure.

  • Turbo 'flutter' is actually your turbo stalling or surging. The flow in your compressor wheel stops momentarily and recirculates internally. Your shaft will then oscillate back and forth as it gains and loses thrust as the flow moves and stalls. Over a period of time you will destroy seals and bearings. I've seen large compressors make themselves very second hand from this very effect. At least a turbo is only 1 compression stage.

  • @Roinik it's fine for diagnositic purposes

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