FAQ: Boost Bypass Valve/Boost Control Solenoid Questions (No Boost)

So i took my engine cover off the other day to change the plugs and wires...and today i opened my hood ( cover still off ) and i noticed my boost bypass valve has completely dissassembled,..further more i looked and it seems like someone used some sort of glue to seal up the vacuum line leading to it... any ideas why this might have been done? and how much are the valves? any help is appreciated.

Check it out man

Link

ok thats good to know because i definitely wanna replace that... thanks...

Cheaper than I thought it was

superchrger is not working feels like a doggy non-supercherged 3800 all the vacumelines are hooked up everything is where it belongs! anybody know wut might be going on?

are the rotors turning? maybe your BBV is stuck open

When did you first notice this?

could be that the coupler has crapped out. Was there any noise under the hood that suddenly went away?

How many miles on the car? Did this happen all of a sudden?

make sure all your wires are hooked up to your plugs. i had a wire come off of one of the plugs one time. Can you still hear the supercharger whine?

yes the wine is still there everything is pluged in and one day it just had no power there is play in the supercharger wheel the motor and supercharger is supose to have 88,000 on them it worked good when i picked it up from the shop there is no skiping or anything its smooth just no power

Then it may be the Boost control solenoid. When they go they tend to just dump boost. They leave you with like 2 or 3 pounds of boost and just dump everything else.

i will check that where is it located?

How'd you make out with this? Any new info?

The BCS/BCA are the black can and black electrical solenoid on the SC right next to the thermostat housing. (top radiator hose).

Deek.. with the alignment if you lost a coupler competely the pins would hit and still turn the charger. I doubt it would be good though.

have not done anything with it its been shitty out so i have not been drivin it

Today I hooked up boost gauge and so it was, no boost. Max 3psi at WOT!

I suspect control solenoid, but I would appreciate tips on troubleshooting.

In the picture below is control solenoid, and one port is open, WHY? May it be the culprit? Please help!



The car is 1997 Riviera.

Btw, I already replaced supercharger coupler and nose bearings, and I hear supercharger whine at WOT, so its not stuck or anything. I also checked that boost valve is moving, when I start the car.

that port should be open. and it is suposed to have a little filter on it but w/e.
still sounds like it could be the control valve or a vac line. does the arm on the BBV fully open/close?

mine did that the other day.
dont know what it was. Just chalked it up to the PCM cutting boost off because of a fueling problem. Normal boost now.

Well, I checked that BBV lever is going up when car is started and when it shut down, lever resting on intake plenum. So it is moving.

What's the good place to shop around for new boost control solenoid? I checked rockauto.com but they doesn't seem to have one...

Find one from other members for $10-15. GM wants about $30-40 IIRC.

mine is only getting about 7psi at WOT

is my BCS going out? Or do you really lose that much boost with a ported SC?

Well, 7psi would be normal. According to 1997 Riviera/Aurora shop manual it should be around 7-9psi, so its ok. Mine is only about 2-3psi at WOT, so its not charging. My PA Ultra is Series I SC engine, and it feels much more quicker than 97 Riv with Series II SC motor, because of low boost.


I tried to eliminate bypass solenoid and even disconnected vacuum line from bypass valve, but its still 2-3psi. I'm hearing some "hissing" sound maybe from under blower, I guess it may be faulty plenum to supercharger gasket or something? I dunno yet.

is the vac line under the blower snout connected?

arttu80 wrote:

Well, 7psi would be normal. According to 1997 Riviera/Aurora shop manual it should be around 7-9psi, so its ok. Mine is only about 2-3psi at WOT, so its not charging. My PA Ultra is Series I SC engine, and it feels much more quicker than 97 Riv with Series II SC motor, because of low boost.


I tried to eliminate bypass solenoid and even disconnected vacuum line from bypass valve, but its still 2-3psi. I'm hearing some "hissing" sound maybe from under blower, I guess it may be faulty plenum to supercharger gasket or something? I dunno yet.

well 7-9 is normal for a 3.8 pulley on a stock motor. I got a 3.25" Sorry, didn't mean to hijack your thread. What was the theory behind bypassing the BCS?

Mr.Riviera wrote:

is the vac line under the blower snout connected?

yes. All my vac lines now run from that one port since I got the newer type SC housing.