Hey everybody, I had a boost actuator that had all the vacume t'* broke so I bought a new one to replace it. Well now I have a weird rattle sound coming from the supercharger, and only about 5psi of boost?? The rattle is bad sounding at idle and it did not do this before?

It would be nice to know what you're driving. We can assume SSEi, but that'* not always the case. And we need to know what year.

1996 Bonneville SSEI

Please edit your profile and put that information in your signature.

This is one section of our Gearhead'* photobucket account. Compare your hookups to these pics and make sure you have it right.

http://s26.photobucket.com/albums/c1...0Supercharger/

Also check the vacuum fitting under the nosedrive of the supercharger.

At idle, disconnect the top vacuum line from the BCA (boost control actuator, large round black thing in this pic):

......and make sure as you disconnect/reconnect that the BCA travels fully, and actuates the bypass valve in the SC a full 90°. Report back what you find.

After that, disconnect the LOWER line (shown in yellow here):

......and plug it at the end of the tube, leaving the other end attached to the BCS (boost control solenoid). This bypasses the PCM'* ability to dump boost. See if you get full boost. Do NOT drive like this full time. It'* a troubleshooting step that could lead to damage.

Let us know what these steps do for you.

vacuum fitting under the nosedrive of the supercharger is hooked up .

BCA travels fully when at idle, and when it is hooked up and disconnected.

When I unhook the BCS I get 1 psi more boost(6#)..

Really no change

What altitude are you at?

I only ask because with a stock 3.8" pulley on both of my cars I only getting 6.5 PSI at the most (3800ft). For 6500 feet at my dads house its around 5.8PSI according to my aeroforce gauge. With a 3.4 pulley, I was only getting around 8 at my dads house

At sea level I gained 2-4 PSI instantly.

Some were wondering how I was able to run a 3.2 with no KR on my car, well I produce a hair shy of 10PSI with a 3.2, vs the 14 PSI i was producing at sea level this past july when I went to the track.

If you are at altitude, and gained 1psi by disconnecting the BCS, I'd suspect a leaky BCS or vacuum leak leading to/from it.

7psi is stock max for your car. 6psi would be explained by the less-dense air at altitude.

Colorado springs (where you just posted from) is 6000 feet.

The day I bought the car boost was 9-10 psi and ran very good. Now the car has the very loud rattle noise sounds like somthing in the charger(did not have before I pulled the old BCA) and now it has a stumble when you hit the gas.

Iam at 5200 ft where I live..

Is the rattle gone now?

Fix the stumble. That'* either fuel or spark related. Boost will probably recover more. The stumble is not boost related.

The car was fine until I parked it to replace the fuel lines(no leaks now),oil change,fuel filter, and the BAC.. Now it sounds and runs like crap....


The rattle is still there .. Sound is there at idle and then you cant really hear the sound when reving the engine do to the supercharger...


I just dont see how the car could act so diffrent, after I did these things....


I have plugs(AL104) and wires on the way, but ive owned lots of boosted factory cars and when I got this one it ran great.

I dont see how maintenance would hurt performance?????