Low or Nonexistant Boost Pressure

INITIAL DIAGNOSIS
1. Using a suitable clamp, pinch closed the charging pressure regulator actuator line (near oil fill tube).
2. Connect charge pressure gauge to intake manifold and test drive vehicle.
3. If charging pressure exceeds 10 psi (0.7 bar), the following components can be considered functional:

^ Charging pressure control valve.
^ Turbocharger.
^ Air circulation valve.

4. Probable defective timing valve.

TIMING VALVE
1. Start engine and quickly accelerate engine. At 60% of air flow sensor operation, the timing valve becomes active.
2. If a light clicking sound form the valve is audible, proceed to step 4.
3. Disconnect timing valve electrical connector.
4. Turn ignition on and measure voltage between red/green lead and ground.

Battery voltage, proceed to step 6.
No battery voltage, proceed to next step.

5. Check wiring between K/CP control unit and timing valve. If OK, replace control unit. End of test.
6. Connect ohmmeter across timing valve connectors.

18 - 45 ohms, proceed to next step.
Not 18 - 45 ohms, replace timing valve. End of test.

7. Apply battery voltage
8. Replace timing valve if it fails to click audibly when energized.
9. Check blue/red wire between K/CP control unit terminal 2 and timing valve.
10. If all tests OK but timing valve still does not function, replace K/CP control unit.
11. Visually check all connecting lines to timing valve, replace as required.
12. Visually inspect rubber air intake cowl, replace as required.


EXHAUST SYSTEM
1. Check exhaust system for leakage or obstructions.
2. Repair as necessary.


TURBOCHARGER
1. Remove air intake cowl from turbocharger.
2. Inspect compressor impeller for chips, cracks or other damage.
3. Check turbocharger shaft by hand for ease of motion and excessive play.
4. Replace as necessary.



BYPASS-AIR VALVE
1. Remove bypass-air valve from intake cowl.
2. Using a vacuum pump, apply 15" in.Hg to valve.

Valve should open and hold vacuum

3. Replace valve if result is not as specified.
4. Reinstall bypass-air valve.
5. Connect vacuum gauge to bypass-air vacuum line.
6. Start and idle engine.
7. If vacuum is not indicated, check line for breakage or obstruction. Repair as necessary.