Engine Ignition System (sti) Subaru Impreza WRX STI GR

SPECIFICATION

ITEM SPECIFICATION

Scheme 6

Tightening torque: N.m (kgf-m, ft-lb)

T1: 21 (2.1, 15.5)

T2: 16 (1.6, 11.8)

CAUTION

1. Wear appropriate work clothing, including a cap, protective goggles and protective shoes when performing any work.
2. Remove contamination including dirt and corrosion before removal, installation or disassembly.
3. Keep the disassembled parts in order and protect them from dust and dirt.
4. Before removal, installation or disassembly, be sure to clarify the failure. Avoid unnecessary removal, installation, disassembly and replacement.
5. Vehicle components are extremely hot after driving. Be wary of receiving burns from heated parts.
6. Be sure to tighten fasteners including bolts and nuts to the specified torque.
7. Place shop jacks or rigid racks at the specified points.
8. Before disconnecting connectors of sensors or units, be sure to disconnect the ground cable from the battery.

REMOVAL

Spark Plug

Refer to "SPECIFICATION" for the spark plug. Ref. to SPECIFICATION , General Description.

Scheme 7

Scheme 8

1. Disconnect the ground cable from the battery.
2. Remove the air cleaner case. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/mechanical/#engine-intake-system-intake-induction-sti) , Air Cleaner Case.
3. Disconnect the connector from ignition coil.
4. Remove the ignition coil. NOTE: Turn #3 ignition coil by 180 degrees to remove it.
5. Remove the spark plug with a spark plug socket.

Scheme 9

Scheme 10

1. Remove the battery. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/charging-system/#starting-system-charging-system-sti) , Battery.
2. Remove the secondary air pump. Ref. to «REMOVAL»(/subaru/impreza-wrx-sti/gr-2007-2011/remont/fuel-system/#aux-emission-control-devices-sti) , Secondary Air Pump.
3. Remove the bolts that secure the air duct to the rocker cover LH, and lift the air duct.
4. Disconnect the connector from ignition coil.
5. Remove the ignition coil. NOTE: Turn #4 ignition coil by 180 degrees to remove it.
6. Remove the spark plug with a spark plug socket.

RH SIDE

Install in the reverse order of removal.

Tightening torque (Spark Plug)

21 N.m (2.1 kgf-m, 15.5 ft-lb)

Tightening torque (Ignition coil)

16 N.m (1.6 kgf-m, 11.8 ft-lb)

LH SIDE

Install in the reverse order of removal.

Tightening torque (Spark Plug)

21 N.m (2.1 kgf-m, 15.5 ft-lb)

Tightening torque (Ignition coil)

16 N.m (1.6 kgf-m, 11.8 ft-lb)

Tightening torque (air pump duct)

9 N.m (0.9 kgf-m, 6.6 ft-lb)

INSPECTION

Check the electrodes and inner and outer ceramic insulator of plugs, noting the type of deposits and the degree of electrode erosion.

Scheme 11

Scheme 12

Scheme 13

Scheme 14

Scheme 15

1. Normal: Brown to grayish-tan deposits and slight electrode wear indicate correct spark plug heat range.
2. Carbon fouled: Dry fluffy carbon deposits on insulator and electrode are mostly caused by slow speed driving in the city, weak ignition, too rich fuel mixture and dirty air cleaner.
3. Oil fouled: Wet black deposits show oil entrance into the combustion chamber through worn rings and excessive clearance between valve guides and stems.
4. Overheating: White or light gray insulator with black or brown spots and bluish burnt electrodes indicate engine overheating, incorrect ignition timing, use of improper fuel, and loose spark plugs.

ADJUSTMENT

Clean spark plugs with a nylon brush, etc. Clean and remove the carbon or oxide deposits. If deposits are too stubborn, replace the spark plugs. After cleaning the spark plugs, measure the spark plug gap using a gap gauge.

Note. Never use a plug cleaner. Never use a metal brush because it makes insulator worn.

Spark plug gap L

0.7 - 0.8 mm (0.028 - 0.031 in)

Scheme 16

Direct ignition type has been adopted. Refer to "Removing Spark Plugs" for removal procedure. Ref. to REMOVAL , Spark Plug.

INSTALLATION

Install in the reverse order of removal.

Tightening torque

16 N.m (1.6 kgf-m, 11.8 ft-lb)

For inspection procedure, refer to "Diagnostics for Engine Starting Failure". Ref. to IGNITION CONTROL SYSTEM , Diagnostics for Engine Starting Failure.

See also:
• REMOVAL
• REMOVAL
• REMOVAL
• IGNITION CONTROL SYSTEM
• SPECIFICATION
• REMOVAL