Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 128

FU(w/o STI)-39

Knock Sensor

FUEL INJECTION (FUEL SYSTEMS)

7. Knock Sensor

A: REMOVAL

1) Disconnect the ground cable from battery.

2) Remove the intercooler. <Ref. to IN(w/o STI)-12,

REMOVAL, Intercooler.>

3) Disconnect the connector from the knock sen-

sor.

4) Remove the knock sensor from cylinder block.

B: INSTALLATION

1) Install the knock sensor to the cylinder block.
NOTE:

The portion of the knock sensor cord that is pulled

out must be positioned at a 60° angle relative to the

engine rear.
Tightening torque:

24 N·m (2.4 kgf-m, 17.7 ft-lb)

2) Connect the connector to the knock sensor.

3) Install the intercooler. <Ref. to IN(w/o STI)-12,

INSTALLATION, Intercooler.>

4) Connect the battery ground terminal.

IN-00203

FU-05716

FU-05750

(A) Front side of vehicle

FU-05751

(A)

60

FU-05716

IN-00203

FU(w/o STI)-40

Knock Sensor

FUEL INJECTION (FUEL SYSTEMS)

C: INSPECTION

1) Check that the knock sensor has no deforma-

tion, cracks or other damages.

2) Measure the resistance between knock sensor

terminals.

Terminal No.

Standard

1 and 2

560±28 kΩ

2 1

EC-02426

FU(w/o STI)-41

Throttle Position Sensor

FUEL INJECTION (FUEL SYSTEMS)

8. Throttle Position Sensor

A: SPECIFICATION

Throttle body is a non-disassembled part, so do not

remove the throttle position sensor from throttle

body.

Refer to “Throttle Body” for removal and installation

procedure. <Ref. to FU(w/o STI)-15, REMOVAL,

Throttle Body.> <Ref. to FU(w/o STI)-16, INSTAL-

LATION, Throttle Body.>

FU(w/o STI)-42

Mass Air Flow and Intake Air Temperature Sensor

FUEL INJECTION (FUEL SYSTEMS)

9. Mass Air Flow and Intake Air

Temperature Sensor

A: REMOVAL

1) Disconnect the ground cable from battery.

2) Disconnect the connector (A) from the mass air

flow and intake air temperature sensor, and re-

move the mass air flow and intake air temperature

sensor.

B: INSTALLATION

Install in the reverse order of removal.
Tightening torque:

1 N·m (0.1 kgf-m, 0.7 ft-lb)

C: INSPECTION

1. CHECK THE MASS AIR FLOW SENSOR

UNIT

1) Connect the battery positive terminal to terminal

No. 3 and the battery ground terminal to terminal

No. 4, the circuit tester positive terminal to terminal

No. 5 and the circuit tester ground terminal to termi-

nal No. 4.

2) Check the voltage changes when air is blown to

the mass air flow sensor unit in arrow direction.

2. CHECK THE INTAKE AIR TEMPERA-

TURE SENSOR UNIT

Measure the resistance between intake air temper-

ature sensor terminals.

3. OTHER INSPECTIONS

1) Check that the mass air flow and intake air tem-

perature sensor has no deformation, cracks or oth-

er damages.

2) Check that the mass air flow and intake air tem-

perature sensor has no dirt.

IN-00203

FU-05798

(A)

5 4 3 2 1

FU-04062

V

Temperature

Terminal No.

Standard

–20°C (–4°F)

1 and 2

16.0±2.4 kΩ

20°C (68°F)

2.45±0.24 kΩ

60°C (140°F)

0.580±0.087 kΩ

FU-04063

FU-04064

5 4 3 2 1