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  1. #1

    '04 MSX 150 wastegate Solenoid

    2004 MSX 150

    Hey, guys (or girls, if that's the case):

    I've had a couple of threads going back and forth about my wastegate problems. I'm making a new thread because I want to know info about a specific part.

    So, the MSX 150 is running perfectly with the exception of the wastegate. I've been calling around to find a ski shop with Digital Wrench so I can see if my wastegate solenoid is showing up as bad. Nearest dealer is over 200 miles away.

    Using compressed air, I checked out the:
    1. Wastegate Actuator, its linkage to the wastegate arm, and the arm itself. Desperado sent me details on how to make certain the wastegate arm begins to move at 6lbs of gradually increased pressure, and that is exactly what it does.

    2. The hose running between the actuator and the wastegate solenoid. No leaks, and both ends of the hose are clamped securely.

    3. The hose running from the wastegate solenoid and the turbocharger. Same as above.

    The turbo is working, but the wastegate arm moves only a little.
    Wastegate arm has no resistence, and when unhooked completely, it flops back and forth freely.
    Fuel pressure is within specs.
    Spark plugs are new and properly gapped
    Compression tests on both cylinders are within spec.
    So I'm down to the solenoid, which after all of the above, is what I'm asking about in this post.

    Can anyone tell me exactly how the solenoid works? I don't mean its function, or what it does for the turbo and engine. I mean, what happens inside the solenoid.

    The hose running from the turbo to the solenoid goes straight in to the rear of the solenoid. The hose fitting that makes a ninety degree turn and comes UP out of the solenoid is where the other end of the actuator/solenoid hose goes. The unoccupied hose fitting on the front of the solenoid is a vent.

    If all that is correct, then how does the solenoid work? What is the state of the solenoid on a ski that is working properly? If the engine if off and the lanyard pulled, should air go through the solenoid unhindered, and is the state of the solenoid the same whether the solenoid is on the ski but the ski turned off, as compared to the solenoid's electrical connection being unhooked.

    To wrap it up, I'm asking when the ski is off, or under low rpms, should the solenoid be open or closed?

    And when the ski is running, but under low rpms, should the solenoid be open or closed.

    And, obviously, under boost the solenoid is supposed to be open (although I understand that it pulses).

    My current solenoid, when unhooked from ski and without power, is wide open. And when 12v is applied to the pins, it closes.

    When the ski is idling, does the ecu keep the solenoid open and then closes it when triggered, or is it the other way around. Shouldn't it be closed while idling, and then open as need demands?

    Thank you all for your patience.

  2. #2
    Wastegate Solenoid 2004 msx 150
    Is there anybody out there? (Can't you just hear Pink Floyd's Comfortably Numb?)

    I put in a lot of gobbleygook in the post above, but that was just because I wanted to recap my problem.
    Since no one responded, I thought I'd restate my questions more directly:

    Does anyone know if the Normal Operation for the wastegate solenoid on the '04 MSX 150 to be closed at idle, low RPMS, and when the ski is turned off, or is the wastegate solenoid's Normal Operation to remain open at idle, low RPMS, or when the ski is turned off?

    Thanks a heap. Is it just me, or are a lot of members not coming on Greenhulk as much as they used to? I've been out on the ski a fair amount, so I imagine that's what everyone else is doing, too--which is what this forum is all about, isn't it? That qualifies as a Duh! moment, I think. We fix 'em in the winter, so we can ride the crap out of 'em in the summer, stopping only when it gets too cold and we have to be chipped off our skis, which, in my case, is about mid November.

    Anyway, ride well, but ride safely.


  3. #3

    Join Date
    Apr 2010
    Stamford CT
    Here is some text from the service manual:


    The amount of pre-compressed intake air generated by the compressor impeller is called boost pressure. Intake boost pressure rises and falls in direct relation to turbine / impeller speed. Excessive boost pressure is a destructive force and therefore is constantly monitored and adjusted by the ECU.

    The wastegate solenoid and wastegate actuator are two critical components responsible for allowing the ECU to control boost pressure.

    During operation, a small amount of pre-compressed air is routed to the wastegate solenoid. The wastegate solenoid is electronically controlled by the ECU. Once opened by the ECU, the wastegate solenoid routes pre-compressed air to the wastegate actuator.

    The wastegate actuator houses a belows, spring, and actuator arm. The actuator arm is connected to a small door located inside of the turbine housing. The actuator arm is held in the closed position by the spring. The belows is exposed to boost pressure whenever the wastegate solenoid is opened. The actuator arm is pushed open when the boost pressure acting upon the belows overcomes the spring pre-load. This action opens the small door inside the turbine housing allowing the exhaust gases to bypass the turbine blades.

    Allowing the exhaust gasses to bypass the turbine blades decreases the turbine / impeller shaft RPM, and lowers boost pressure.

    In a few of desperado's earlier posts he noted that the boost map is not linear and that it is a targeted value. In order to achieve the targeted value (any boost above the 6 psi break away of the wastegate) the ECU to going to have to cycle the wastegate solenoid on/off. It is my understanding that the solenoid, in its off (ECU output inactive) position will provide a direct path from the compressed air of the turbo outlet to the wastegate actuator, effectively limiting boost to approx. 6psi (the break away point of the actuator spring). When the solenoid is energized (ECU output active) then the actuator is going to be exposed to atmospheric pressure and the wastegate (bypass valve inside the exhaust manifold) will remain closed allowing the turbo to build boost.

  4. #4
    Thank you so much. That is exactly what I was looking for. I answered your PM first, and thanks for that, by the way, but ignore it, because you have given me what I needed to move forward. Desperado's back as well, and I'm also waiting to see what he saw about some particulars.
    Thanks again,

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