Tech Tip No. 15

Ned Ritchie

Originally published in the quattro quarterly

Copyright 1996

Engine Stalling - Leaking Bypass Valve

This valve is found on all 20-valve turbo engines beginning in 1991.

The valve reduces the peak pressure spike when the throttle plate slams closed during each gear shift, saving the intercooler from rupturing, and keeps the turbo spinning during the shift. In some cases it even reduces turbo lag.

However when the valve leaks or the hose from the intake manifold which operates the valve with vacuum and pressure is pinched, or cracked maximum boost pressure is reduced.  In addition when the valve leaks the engine will stall after pushing the car hard when you come up to a traffic stop.

Replacing this valve will return maximum power and eliminate the stalling problem.

INTENDED ACCELERATION ^®

© Copyright 1997-2000 by Ned Ritchie