Boost Spike Issue
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This is a discussion on Boost Spike Issue within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; I have a 2002 WRX with 62k on the clock. I had the 60k service performed 3 weeks ago. I've ...

  1. #1
    Registered User Shadow's Avatar
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    Boost Spike Issue

    I have a 2002 WRX with 62k on the clock. I had the 60k service performed 3 weeks ago. I've noticed in the last week that the turbo boost is "spiking" when at full throttle. Regardless of gear, sometimes, when I go full throttle, the boost gauge goes to ~.11 MPa, then down to ~.09 MPa. Then back up to .11MPa and back down to .09 MPa. This contiues until I lift off the throttle. If I slowly apply pressure to the throttle until full throttle is reached, this does not occur, but sometimes it does, irregardless of the type of throttle application.

    I'd like to diagnose this ASAP, so if anyone knows what I am experiencing I would really appreciate a response. Thanks.

    -Shadow
    2002 Subaru Impreza WRX Sedan 5MT - Midnight Black Pearl
    2009 Subaru Impreza WRX Wagon 5MT - Dark Gray Metallic

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  3. #2
    Registered User b_vargo21's Avatar
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    Quote Originally Posted by Shadow
    I have a 2002 WRX with 62k on the clock. I had the 60k service performed 3 weeks ago. I've noticed in the last week that the turbo boost is "spiking" when at full throttle. Regardless of gear, sometimes, when I go full throttle, the boost gauge goes to ~.11 MPa, then down to ~.09 MPa. Then back up to .11MPa and back down to .09 MPa. This contiues until I lift off the throttle. If I slowly apply pressure to the throttle until full throttle is reached, this does not occur, but sometimes it does, irregardless of the type of throttle application.

    I'd like to diagnose this ASAP, so if anyone knows what I am experiencing I would really appreciate a response. Thanks.

    -Shadow
    i've been having the same problem... i'm at about 72k, just started doing it a couple days ago...
    "Its only illegal if you get caught"

    Blobeye Syndicate #5
    Catless VF34

  4. #3
    Registered User PKer's Avatar
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    I was getting scary boost spikes up to 1.5 bar ~21-22psi! Now everything is under control again.

    Try this:
    Run a line from the nipple on the turbo straight to the wastegate actuator. This effectively bypasses the factory boost control solenoid.
    Go drive should not boost higher than 7psi or .5 bar.

    If this works you eliminated the actuator as the cause.

    Next remove the factory boost control solenoid from the car and try cleaning it with non-chlorinated brake cleaner (spray it in there good and let it dry a few times).
    Sometimes it sticks in the open or closed position causing too much or too little boost.

    Unfortunately for me cleaning the solenoid didn't work for me, and I had to buy a new one from the dealer ~125 bucks. There are a few aftermarket solenoids, prodrive and others, even the GM boost control solenoid from their 80's turbo cars work quite well. I did not take advantage of them because my car is used mainly for autocross, and they would be illegal from a classing stanpoint.

  5. #4
    Registered User b_vargo21's Avatar
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    well mine seemed to be a much cheaper fix!! a good bootle of fuel system cleaner and a fresh tank of sunoco 94!!! she is runnin like a champ now!!!
    "Its only illegal if you get caught"

    Blobeye Syndicate #5
    Catless VF34

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