supercharger has lost its whine :(

**ck1racer** · 09-04-2010

Hello to everyone here at GPforums, this is my 1st post. I have a 99 GTP with 152,000 miles, its had a recent tune up, plugs, wires, fuel filter ect....My wife normaly drives this car and i am just finding out after a 600 mile round trip that the supercharger isnt working. the boost guage only goes up a 1\4 of the way at full throttle, no whine and the motor feels dead. Just had the converter and resinator replaced before our trip and got an average of 27 to 28 mpg. I need help diagnosing this problem? Please help!!

**Sandman** · 09-04-2010

How's your belt? Assuming no codes?

**CTKGP09** · 09-04-2010

check the belt and pulley to make sure they are all working, after that take the supercharger belt off and spin the pulley and see what you hear/feel

**Dragon1972** · 09-04-2010

I agree, but also pay attention to any "slop" in the pulley and rotors, sounds to me that your couplers are badly worn out. ZZP has replacements with the oil needed after you are done replacing.

**01gpgt01** · 09-05-2010

BBV valve Would be where id start

**Dragon1972** · 09-05-2010

Real simple, just take off the vac hose, plug it and test run. BBV is manually set to 10 psi.

**ck1racer** · 09-05-2010

BBV? Is that like a blow off valve or a boost cut cut off? If was stuck open would there be any boost at all? Because there is some, just not very much.

**SDGTP99** · 09-05-2010

Check for vacuum leaks or a griding noise in the supercharger. Are you throwing any codes?

**Sandman** · 09-05-2010

Originally Posted by ck1racer

BBV? Is that like a blow off valve or a boost cut cut off? If was stuck open would there be any boost at all? Because there is some, just not very much.

It's a bypass valve that doesn't let the blower build boost constantly. It's vacuum controlled so when you give it more throttle it closes more. If it's starting to go out it won't close all the way and you'll only get partial boost. I went through the same thing a year ago, could only build like 4lbs peak on stock pulley.

**ck1racer** · 09-05-2010

Thanks to everyone who has posted. I have a place to start now, all of you have been very informative. Thank You!!

**CTKGP09** · 09-05-2010

now get your whine back!

**ck1racer** · 09-05-2010

I went to ZZP and was reading their tech article on the boost bypass valve. I loosened the nuts on the valve, pushed it down and tightened. I test drove it and i got boost! I wounldnt say its 100% but definatly made a difference. I thought i would share that with everyone. Thanks again!

**CTKGP09** · 09-05-2010

interesting

**matt5112** · 09-05-2010

its just going to deteriorate more then you'll still need a new one...

**Bio248** · 09-05-2010

you just screwed up how the valve works. AWESOME.

**blueguy** · 09-06-2010

Put it back to the factory place and buy a new one...cheapo...don't ghetto rig sh1t. Go read my Safely Modding thread if you want good info on these cars jeeves.

**ck1racer** · 09-06-2010

Ghetto? Its not ghetto, its a temporary fix for now. Its not like Jo Blow at the local used car lot told me to do this, its on zzperformance's website. The blower needs to come off i know but not now. Thanks for your help!