Engine Intake System - Intake (Induction) (Sti): Diagnosis Subaru Impreza GH

INSPECTION

Replace if excessively damaged or dirty.

Scheme 39

Scheme 40

1. Disconnect the ground cable from battery.
2. Remove the air intake duct. REMOVAL, Air Intake Duct.
3. Disconnect the connector (A) from air flow and intake air temperature sensor.
4. Loosen the clamp (B) which holds the air intake boot.
5. Remove the clip (C) from the air cleaner case (front).
6. Remove the air cleaner case (rear) and air intake boot.
7. Remove the air cleaner element.
8. Remove the bolt (A) and nut (B) which secure the air cleaner case (front) to the body.
9. Remove the air cleaner case (front).

Scheme 41

Scheme 42

1. Install the bolt (A) and nut (B) which secure the air cleaner case (front) to the body. Tightening torque: Bolt (A) 6 N.m (0.6 kgf-m, 4.4 ft-lb) Nut (B) 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)
2. Install the air cleaner element.
3. Install the air cleaner case (rear) and air intake boot. NOTE: When installing the air cleaner case (rear), align the protrusion of the air cleaner case (rear) to the hole on the air cleaner case (front) to install. Tightening torque: 2.5 N.m (0.3 kgf-m, 1.8 ft-lb)
4. Install the clip (B) to the air cleaner case (front).
5. Connect the connector (A) to the mass air flow and intake air temperature sensor.
6. Install the air intake duct. INSTALLATION, Air Intake Duct.
7. Connect the ground cable to battery.

Check for cracks or loose connections.

1. Check for cracks or loose connections.
2. Inspect that no foreign objects in the air intake duct.

Scheme 43

1. Disconnect the ground cable from battery.
2. Remove the intake manifold. Ref. to «REMOVAL»(ref-357081-S32531544052010030800000) , Intake Manifold.
3. Remove the sensor, engine harness and fuel pipe attached to the intake manifold. Ref. to «DISASSEMBLY»(ref-357081-S32495806972010030800000) , Intake Manifold.
4. Remove the intake duct from intake manifold.

Check for cracks or loose connections.

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Scheme 51

1. Set the vehicle on a lift.
2. Disconnect the ground cable from battery.
3. Lift up the vehicle.
4. Drain approximately 3.0 l (3.2 US qt, 2.6 lmp qt) of coolant. Ref. to «DRAINING OF ENGINE COOLANT»(ref-357080-S30342819572010030800000) , REPLACEMENT, Engine Coolant.
5. Lower the vehicle.
6. Remove the intercooler. REMOVAL, Intercooler.
7. Remove the intercooler stay.
8. Remove the center exhaust pipe. Ref. to «REMOVAL»(ref-357090-S31053857072010030800000) , Center Exhaust Pipe.
9. Lower the vehicle.
10. Remove the joint pipe from the turbocharger.
11. Disconnect the engine coolant hose from the upper side of the water pipe.
12. Disconnect the air control hose (A), and loosen the clamp holding the intake duct to the turbocharger.
13. Remove the oil inlet pipe from the turbocharger.
14. Disconnect the engine coolant hose from the lower side of the water pipe.
15. Disconnect the oil outlet hose from the oil outlet pipe, and remove the turbocharger.
16. Remove the turbocharger stay.

Scheme 52

Scheme 53

1. Install the turbocharger stay. Tightening torque: T1: 33 N.m (3.4 kgf-m, 24.3 ft-lb) T2: 42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
2. Connect the oil outlet hose to the oil outlet pipe.
3. Connect the engine coolant hose to the lower side of the water pipe.
4. Install the oil inlet pipe to turbocharger. NOTE: Use a new gasket. When tightening, never rotate the part indicated as (A) in the figure. Tightening torque: T1: 16 N.m (1.6 kgf-m, 11.8 ft-lb) T2: 20 N.m (2.0 kgf-m, 14.8 ft-lb)
5. Connect the air control hose (A), and install the intake duct to the turbocharger. Tightening torque: 3 N.m (0.3 kgf-m, 2.2 ft-lb)
6. Connect the engine coolant hoses to the upper side of the water pipe.
7. Install the joint pipe to turbocharger. NOTE: Use a new gasket. Tightening torque: 42.5 N.m (4.3 kgf-m, 31.3 ft-lb)
8. Lift up the vehicle.
9. Install the center exhaust pipe. Ref. to «INSTALLATION»(ref-357090-S07931192752010030800000) , Center Exhaust Pipe.
10. Lower the vehicle.
11. Install the intercooler stay. Tightening torque: 16 N.m (1.6 kgf-m, 11.8 ft-lb)
12. Install the intercooler. INSTALLATION, Intercooler.
13. Connect the ground cable to battery.
14. Fill engine coolant. Ref. to «FILLING OF ENGINE COOLANT»(ref-357080-S19402554772010030800000) , REPLACEMENT, Engine Coolant.

Scheme 54

Scheme 55

1. Remove the intercooler. REMOVAL, Intercooler.
2. Remove the turbocharger upper cover.
3. Remove the boost hose (B) from the waste gate actuator (A) of the turbocharger, and connect the Mighty Vac to the waste gate actuator (A).
4. Pressurize slowly with the Mighty Vac, and measure the pressure when the control rod stroke (D) becomes 2 mm (0.08 in). If it is not within the standard, replace the turbocharger assembly. CAUTION: Do not pressurize over 89.9 kPa (0.92 kgf/cm 2 , 13.0 psi) to prevent damaging the waste gate actuator. Operating pressure (Control rod stroke 2 mm (0.08 in)): Standard 74.7 - 80.8 kPa (0.76 - 0.82 kgf/cm 2 , 10.8 - 11.7 psi)
5. After inspection, install the related parts in the reverse order of removal. Tightening torque: 7.5 N.m (0.8 kgf-m, 5.5 ft-lb)

Check for cracks or loose connections.