Boost Pressure

Ensure there is no leaks on intake or exhaust gas side. To test the turbocharging system, use a pressure gauge (VW 1397). The gauge is equipped with a valve which locks pressure measurement when closed.
CAUTION: When testing turbocharger, test time per measurement must not exceed 10 seconds.
Attach gauge to the boost pressure line at the fuel injection pump, using "T" fitting supplied with gauge. Use hose clamps at all connections.
Boost pressure can only be tested on a chassis dynamometer or through road testing. Carry the gauge inside car by routing the hose out right rear corner of hood and into passenger side vent wing window. Boost pressure to be measured with engine at full throttle during road test or on dynomometer.
Open gauge stop valve. On dynamometer, engine must be at 4000 RPM. Manual transmission must be in 3rd gear and automatic transmission in 2nd range. On road test, manual transmission must be in 2nd gear and automatic transmission in 1st range. Hold vehicle speed to 60 MPH using brake.
Boost pressure must be 9-10 psi (.6-.7 kg/cm² ). If boost pressure is too high, replace wastegate.
If pressure is too low, disconnect and plug blow-off valve hose from intake air hose. Repeat boost pressure test.
If pressure is okay, replace blow-off valve. If pressure is too low, replace wastegate. Repeat pressure test. If pressure specification is not obtained, replace turbocharger.