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Old 04-13-2008, 08:42 PM   #1
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Default lim, sc, valve cover change, NOW only 2psi boost?

when i give it just a little bit of throttle it goes to zero, then i have to realllllly pus down on the gas to get it over 0. if i go WOT it goes to about 2 psi. smooth.. but not nearly the same boost as before 9+ pounds.. any ideas on what i should for?
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Old 04-14-2008, 09:49 AM   #2
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bump.. I searched and found some problems exactly like mine, but the people never came back and posted the solution ?

Gonna go over all the vacuum lines in the mean time..

Again, everything seems great until i'm WOT. Normal acceleration is reflected perfectly on the gauge. Just WOT is weak !! ( Gauge makes full sweep, and i dont doubt the accuracy bc it feels like the SC is barely making boost, so it'* not the gauge )
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Old 04-14-2008, 10:31 AM   #3
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Might be that your boost bypass is stuck wide open.
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Old 04-14-2008, 11:02 AM   #4
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At idle, remove the top vacuum line from the BCA. Does the BCA fully travel? Or is it bound up?
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Old 04-14-2008, 04:55 PM   #5
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Im not too sure what the BCA is, or the BCS.. can someone tell me exactly what they are, function, PIC?

Thanks.. i know that the " butterfly" on the bottom of the SC ( now installed though ) is TIGHT. it wont push down to the the "stop" nut thats on the SC.. (the canister with the silver pole sticking out of it in the front on the SC )
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Old 04-14-2008, 05:29 PM   #6
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The canister with the silver pole is the BCA. Boost control Actuator. The BCS (boost control solenoid) is the small thingy with the vacuum line between it and the BCS, and an electrical connector the PCM uses to command boost or not.

If your bypass valve won't full close, you need to hope you can lubricate the ends of the bypass shaft in the front and rear of the SC and work it open and closed to free it up. That'* your problem. The bypass won't fully CLOSE, limiting your peak boost.
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Old 04-14-2008, 05:32 PM   #7
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This is a BCA:



This is one on a supercharger.

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Old 04-14-2008, 05:48 PM   #8
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ok.. im so fed up with this damn bonneville.. its always something.

I took the BCA OFF the car. plugged the vacuum port on the electrical thing thats bolts to it, and set that on the valve cover. I then plugged the air distributer port ( little black box atop the SC witht the sticker gasket )

THEN I PUSHED HARD on the black lever all the way to the stop pin.

Took car for a spin. WOT got 7psi. So it is defintely the "bypass valve" on the SC.. looks like im gonna have to pull it and fiddle with it.. ALSO:

It made 9+ lbs before, now only 7. is it because I took some thing out of the sytem with what i described above, or does it need to be "broken in".. I think im gonna put my "old BAD COUPLER, NO OIL WHATSOEVER in it when i pulled the plug after removal", SC back on, get my 9 psi and just return this one if its only gonna give me 7.. thats a 20 hp loss, correct?

It feels like MUCH less boost...
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Old 04-14-2008, 05:51 PM   #9
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Your sealing job for testing was leaking under pressure.

Do NOT take the supercharger off yet. Try what I just posted first. Look at my previous reply (clearly detailed first step for a bound up bypass valve).
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Old 04-15-2008, 10:36 PM   #10
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and you dont want to remove the bca either. you dont want boost all the time. it needs to be bypassed. follow Bills advice in his previous post.

if you need a new bca, lmk, i have a couple layin around.
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