Supercharger or pulley died? Stalls/dies at low RPM/idle/neutral

Red '89 SC

Registered User
89 SC, just cleared 153K miles on a 9 hr road trip (1st extended drive in years...yah, I know). Boost gauge stopped working, stays in "VAC", barely goes into "HG" or boost when I jam the gas or lay off it. Loud whining noise (not the whine of the supercharger) when I am on the gas, car stutters at lower RPM (2-3K). When close to idle RPM or in neutral, car stalls fast, dies. When I re-start car, I have to rev RPMs and slip it into 1st real quick to get moving. Other than that, once in gear with good RPMs, runs smooth!

Is supercharger dead/dying or is it a dead pulley slowing down the serpentine belt or other belt causing car to stall/die when low RPM or in neutral/at a stop? Definitely no acceleration when I hit the gas and can't hear the air flowing thru the supercharger. Thought car would run and not stall even with supercharger disconnected/not working -- thoughts? Also looking for a good mechanic/shop in C Springs or Denver.

Wish I could divorce myself of this car but I'm hooked!
 
I would say you have a vacuum leak and sounds like its to the boost gauge is where it is leaking from

Ditto...classic signs of a vacuum leak. Not sure if it's the gauge hose because it's so small it doesn't usually cause enough of a leak to stall the motor. Since you mentioned a constant whining noise I would look at the vacuum hose attached to the bypass valve actuator. Sounds like the hose to it fell off or is leaking and the bypass valve is stuck in the closed position.

David
 
That would make more sense david I just thought the hose for gauge could be leaking as well because he said it barely moves. Hate those vacuum leaks either way big or small LOL
 
Extremely easy to rule out the blower. Take the belt off. It just takes an 18mm wrench (though an extra pair of hands would be helpful for slipping the belts back over the pulley when done).
 
Sounds exactly like when I goofed up the gasket on the return plenum and it was sucking air. Spit, cough, never get into boost yet a whine similar to the blower.
 
Thanks!

Thanks for the tips! Since you all mentioned a vac problem, I started by looking for loose hoses, etc. After 20min of looking, I noticed the obvious...the 'coupler' that connects the intercooler tube to the top of the supercharger was so loose that the tube was barely connected to the supercharger. Tightened it back up, she's back to normal - good idle, no stalls in neutral, no loud whining noise.

I assume there's really no way for that to come loose in normal driving if it's tightened...last thing I had done on the car was ABS work about 10 days ago, maybe the mechanic 'forgot' to tighten it down? Anyhow, thanks again for your tips and advice, saved me from atleast a $100 diagnostic.
 
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