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Old 08-21-2004, 08:01 PM   #1
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Default Boost Actuator / Valve

Checked the vacuum line going to the actuator and it seems fine..

My bro thinks its the actuator thats gone.. and not the BCS.

I'd like to know.. if there'* any way we can tell if it'* the actuator thats gone or the Solenoid?

Secondly.. on the actuator.. theres a lil bar that goes to an "L" shape that goes into the */C *Merlin mentioned to check that* So my question is when it'* down.. is it
a.) dumpin boost in that position (open) or close the valve??
b.) Is the actuator controlled by pressure or vacuum? ( Same with the BCS )

My bro wants me to go see him sometime this week and he'll put a vacuum line checker thing on the lines to check.. anyone know what it should read??
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Old 08-22-2004, 02:35 AM   #2
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The actuator holds the bypass gate open under vacuum. Like when you take your foot off the throttle and the vacuum rises, the boost bypasses. When you are under boost and the PCM commands removal of boost, the bypass solenoid, which is connected to the exhaust side of the supercharger, opens to pressurize the opposite side of the actuator air diaphram, thus opening and dumping boost.
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Old 08-22-2004, 09:58 PM   #3
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When the car is off... that L shaped thing should be sitting ontop of a bolt/screw on the SC.

Now... watch it... and get someone to start your car... the rod connecting to the L shaped thing will get SUCKED up when the engine starts, and thus lift off the screw/bolt.

When gas is applied, the BCV will push the L thing down until it hits the screw/bolt, when that happens you are getting full boost.

I suggest removing the BCS and BCV, play with the L shaped lever and make sure it moved easy. Also play with the BCV and see how it feels.

BTW Drifter... I do have the BCS and BCV here... let me know if you want them.... I'll have to return them sometime soon if you don't.
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Old 08-23-2004, 01:19 PM   #4
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K.. thanx folks.. I will have to check it out.. I checked the top vacuum line for the Actuator/valve and it seems fine on both side.. I did the BCS bypass trick already.. so is there a point to even check the vacuum line goin to it? I will have to check it out later anyways.. and take the BCA/BCV off to check as Merlin has mentioned. ( I am able to move it from the engine when it'* off.. and it seems fine.. but will check and see
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Old 08-23-2004, 01:51 PM   #5
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Murdock, I think the best way to check the BCA is to use two people. Like I suggested before, block the wheels, set the brake, put Tam in the car in gear, and have her power brake it up to 4000 rpms. Up and down, while you watch the BCA.
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Old 08-23-2004, 02:06 PM   #6
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Quote:
Originally Posted by willwren
Murdock, I think the best way to check the BCA is to use two people. Like I suggested before, block the wheels, set the brake, put Tam in the car in gear, and have her power brake it up to 4000 rpms. Up and down, while you watch the BCA.
Thats if I can peel her off the computer Bill.. hahahahaha.. anywho.. So when the car starts.. the lever should be up *the "L" from the supercharger and when starting to boost.. it should go down and be touchin @ the bottom right? Will have to check that out ASAP.. and thanx for holdin on to the parts for me Merlin
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Old 08-23-2004, 09:24 PM   #7
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No problem Drifter.... they are here if you need em.
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Old 08-24-2004, 10:16 AM   #8
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Another quick note when checkin the actuator.. out of curiousity.. since we'll be using a vacuum gauge also.. I just want to confirm that the Actuator/valve shouldn't have any leak in between both chambers right?
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Old 08-27-2004, 02:31 PM   #9
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OK.. puttin this out to see what everyone thinks.. I dump boost when not @ wot.. but when I went WOT last weekend.. I notice I get full boost and maintain it. What gives? Something have to do with pressure/vacuumm lines? Since I"m assuming @ WOT vacuum is '0'
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Old 08-30-2004, 12:05 AM   #10
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Hey Drifter, I just had to replace my actuator valve. Here is an easy way to test it. Put a hose on the vacuum connection on the outer chamber and suck on it. The actuator rod should pull all the way in and stay there. Mine had a major leak and would not pull in at all. The new one pulls the rod all the way in when the car is in park at idle. Be carefull not to break the plastic valve off of the metal bracket or the vacuum connections off of the valve. The plastic gets brittle with age and I broke mine. The new one is expensive. $350.00 from the dealer unless you know someone who can get you a deal on it.
I also found several of the small rubber fittings were leaking as well as a large rubber "T" in the same area. You can get these at the dealer for under $10.00.
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