Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual - part 25

2014 IMPREZA WRX STI SERVICE MANUAL

QUICK REFERENCE INDEX

FUJI HEAVY INDUSTRIES LTD.

G1180BE2

ENGINE 1 SECTION

This service manual has been prepared
to  provide  SUBARU  service  personnel
with the necessary information and data
for  the  correct  maintenance  and  repair
of SUBARU vehicles.
This  manual  includes  the  procedures
for  maintenance,  disassembling,  reas-
sembling, inspection and adjustment of
components  and  diagnostics  for  guid-
ance of experienced mechanics.
Please  peruse  and  utilize  this  manual
fully to ensure complete repair work for
satisfying  our  customers  by  keeping
their  vehicle  in  optimum  condition.
When  replacement  of  parts  during
repair  work  is  needed,  be  sure  to  use
SUBARU genuine parts.

All  information,  illustration  and  specifi-
cations  contained  in  this  manual  are
based on the latest product information
available  at  the  time  of  publication
approval.

FUEL INJECTION (FUEL SYSTEMS)

FU(STI)

EMISSION CONTROL 
(AUX. EMISSION CONTROL DEVICES)

EC(STI)

INTAKE (INDUCTION) 

IN(STI)

MECHANICAL

ME(STI)

EXHAUST

EX(STI)

COOLING

CO(STI)

LUBRICATION

LU(STI)

SPEED CONTROL SYSTEMS

SP(STI)

IGNITION

IG(STI)

STARTING/CHARGING SYSTEMS

SC(STI)

FUEL INJECTION (FUEL SYSTEMS)

FU(STI)

Page

1.

General Description  ...................................................................................2

2.

Throttle Body ............................................................................................15

3.

Intake Manifold .........................................................................................17

4.

Engine Coolant Temperature Sensor .......................................................34

5.

Crankshaft Position Sensor ......................................................................35

6.

Camshaft Position Sensor ........................................................................37

7.

Knock Sensor ...........................................................................................40

8.

Throttle Position Sensor ...........................................................................41

9.

Mass Air Flow and Intake Air Temperature Sensor  .................................42

10.

Manifold Absolute Pressure Sensor .........................................................43

11.

Fuel Injector  .............................................................................................45

12.

Tumble Generator Valve Assembly  .........................................................48

13.

Tumble Generator Valve Actuator ............................................................49

14.

Oil Flow Control Solenoid Valve ...............................................................50

15.

Wastegate Control Solenoid Valve  ..........................................................52

16.

Front Oxygen (A/F) Sensor  ......................................................................54

17.

Rear Oxygen Sensor ................................................................................56

18.

SI-DRIVE (SUBARU Intelligent Drive) Selector  .......................................58

19.

Engine Control Module (ECM)  .................................................................59

20.

Main Relay  ...............................................................................................60

21.

Fuel Pump Relay ......................................................................................62

22.

Electronic Throttle Control Relay  .............................................................64

23.

Fuel Pump Control Unit ............................................................................66

24.

Fuel  ..........................................................................................................67

25.

Fuel Tank  .................................................................................................70

26.

Fuel Filler Pipe  .........................................................................................77

27.

Fuel Pump ................................................................................................80

28.

Fuel Level Sensor  ....................................................................................82

29.

Fuel Sub Level Sensor .............................................................................83

30.

Fuel Filter  .................................................................................................85

31.

Pulsation Damper Assembly  ....................................................................89

32.

Pressure Regulator & Damper Assembly  ................................................90

33.

Purge Damper ..........................................................................................92

34.

Fuel Delivery, Return and Evaporation Lines ...........................................93

35.

Fuel System Trouble in General  ..............................................................98

FU(STI)-2

General Description

FUEL INJECTION (FUEL SYSTEMS)

1. General Description

A: SPECIFICATION

Fuel tank

Capacity

64 L (16.9 US gal, 14.1 Imp gal)

Location

Under rear seat

Fuel pump

Type

Impeller

Shutoff discharge pressure

900 kPa (9.18 kg/cm

2

, 130.5 psi), or less

Discharge rate

175 L (46.2 US gal, 38.5 Imp gal)/h or more

[12 V at 300 kPa (3.06 kg/cm

2

, 43.5 psi)]

Fuel filter

In-tank type

FU(STI)-15

Throttle Body

FUEL INJECTION (FUEL SYSTEMS)

2. Throttle Body

A: REMOVAL

1) Disconnect the ground cable from battery.

2) Lift up the vehicle.

3) Remove  the  under  cover.  <Ref.  to  EI-28,  RE-

MOVAL, Front Under Cover.>

4) Drain approximately 3.0 L (3.2 US qt, 2.6 Imp qt)

of  coolant.  <Ref.  to  CO(STI)-13,  DRAINING  OF

ENGINE  COOLANT,  REPLACEMENT,  Engine

Coolant.>

5) Remove  the  intercooler.  <Ref.  to  IN(STI)-12,

REMOVAL, Intercooler.>

6) Disconnect  the  connector  (A)  from  the  throttle

position  sensor,  and  the  connector  (B)  from  the

manifold pressure sensor.

7) Disconnect the engine coolant hose from throttle

body.

8) Remove the throttle body from the intake mani-

fold.

B: INSTALLATION

Install in the reverse order of removal.
NOTE:

Use a new gasket.
Tightening torque:

8 N·m (0.8 kgf-m, 5.9 ft-lb)

C: INSPECTION

1. THROTTLE SENSOR INSPECTION 

(METHOD WITH CIRCUIT TESTER)

1) Remove  the  lower  inner  trim  of  passenger’s

side.  <Ref.  to  EI-57,  REMOVAL,  Lower  Inner

Trim.>

2) Turn over the floor mat of passenger’s seat.

3) Remove the protect cover.

4) Remove the nuts and bolts which hold the ECM

to the bracket.

5) Turn the ignition switch to ON. (engine OFF)

IN-00203

FU-05759

(B)

(A)

FU-05760

FU-05691

FU-03416

FU-03417