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les_garten les_garten is offline
Macht Schnell
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Join Date: Jun 2003
Location: PSL, FL
Posts: 861
Originally Posted by Dan89_930 View Post
Quick recap of the problem - the car sat in the seller's garage for the last 5 years - probably closer to 7 years. When 930's sit without being driven, belts, hoses, gaskets, seals, etc. can fail. At best, most will not function properly.

Until the motor was running nice and warm, I could not get charged air (boost) into the motor. Once the car was warm, boost was mostly normal.

The problem (no boost until the engine got really warm) wasn't the wastegate or the turbo. There is an aluminum alloy tube / pipe / housing that connects the turbo to the intercooler - it called the "valve housing". Inside the valve housing is a piston that slides up and down the housing - its purpose, as I understand it, is to regulate the amount of charged air into the intercooler before, during, and after the engine warms up. The warmer the engine, the more charged air is allowed into the intercooler (not sure this explanation made complete sense, but that's how my mechanic explained things).

At both ends of the housing are "O" rings / gaskets. Because the car had sat for so long, these "O" rings became brittle and cracked and failed. The mechanic took apart the valve housing, found lots of little pieces of those "O" rings and determined the little bits and pieces were causing the piston to not function properly. The mechanic clean up the housing, replaced the "O" rings, reassembled everything and the car now runs perfectly.

I had never heard of this before. I thought it was just a straight shot from the turbo to the intercooler. Interesting, eh?

That is the Shuttle valve, recirculating valve or blow off valve, whichever you want to call it. Makes sense now. Good one!
---Les Garten---85 930, Andial IC, GHL Headers, Fabspeed Dual, K-27 HF2, 3.4 JE Full Finned 7.5:1 CR, 964 CAM'd, Carerra 3.2 Manifold Cut/Flipped, Tec3r, Siemans 55#, GSF Fuel Rails, Clewett Crank Trigger, Clewett Cam Trigger,Dual Plugged, ARP Head Studs/Rod Bolts, Clewett Wires.Tial 46mm WG, Tial 50mm BOV, WEVO Shifter,934 Boost Gauge, Wideband EGO Sensor/Gauge, C2T Head Gaskets, '88 MB 300TE,BMW R100RT
Old 06-10-2008, 05:27 PM
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