1995 SUBARU LEGACY spark plugs

3. Engine Idle Speed
A: MEASUREMENT
1) Before checking idle speed, check the following:
(1) Ensure that air cleaner element is free from
clogging, ignition timing is correct, spark plugs are in
good condition, and that hoses are connected properly.
(2) Ensure that malfunction indicator light (CHECK
ENGINE light) does not illuminate.
2) Warm-up the engine.
G2M0096
3) Connect Subaru Select Monitor or the OBD-II general
scan tool to data link connector.
CAUTION:
When connecting Subaru Select Monitor, turn ignition
switch to OFF.
4) Start the engine and measure engine speed.
NOTE:
Engine speed is indicated on Subaru Select Monitor by
selecting “MODE F04”.
G2M0097
NOTE:

When using the OBD-II general scan tool, carefully read
its operation manual.

When Subaru Select Monitor is not used, attach the
pickup sensor on tachometer (Secondary pickup type) to
#1 cylinder spark plug cord.

This ignition system provides simultaneous ignition for
#1 and #2 plugs. It must be noted that some tachometers
may register twice that of actual engine speed.
3
2-2
3. Engine Idle Speed

4. Engine Compression
A: MEASUREMENT
1) After warming-up the engine, turn ignition switch to
OFF.
2) Make sure that the battery is fully charged.
3) Remove all the spark plugs.
4) Disconnect connectors from fuel injectors.
5) Fully open throttle valve.
6) Check the starter motor for satisfactory performance
and operation.
G2M0098
7) Hold the compression gauge tight against the spark
plug hole.
CAUTION:
When using a screw-in type compression gauge, the
screw (put into cylinder head spark plug hole) should
be less than 18 mm (0.71 in) long.
8) Crank the engine by means of the starter motor, and
read the maximum value on the gauge when the pointer is
steady.
9) Perform at least two measurements per cylinder, and
make sure that the values are correct.
Compression (200—300 rpm and fully open throttle):
Standard
1,079—1,275 kPa
(11.0—13.0 kg/cm
2, 156—185 psi)
Limit
883 kPa (9.0 kg/cm
2, 128 psi)
Difference between cylinders
196 kPa (2.0 kg/cm
2, 28 psi)
5
2-2
4. Engine Compression

TROUBLE
Engine will not start.
Rough idle and engine stall
Low output, hesitation and poor acceleration
Surging
Engine does not return to idle.
Dieseling (Run-on)
After burning in exhaust system
Knocking
Excessive engine oil consumption
Excessive fuel consumption Starter does not turn.
Initial combustion does not occur.
Initial combustion occurs.
Engine stalls after initial combustion.
INTAKE SYSTEM
2111 3Loosened or cracked intake air pipe
3111 3 1Loosened or cracked blow-by hose
31211 2Loosened or cracked vacuum hose
22222Defective intake manifold gasket
22222Defective throttle body gasket
322 2 2Defective PCV valve
222 323Loosened oil filler cap
3312 1Dirty air cleaner element
FUEL LINE
13 322Defective fuel pump and relay
33322Clogged fuel line
222233Lack of or insufficient fuel
BELT
222Defective
222322 22 2Defective timing
FRICTION
3Seizure of crankshaft and connecting rod bearing
3Seized camshaft
3Seized or stuck piston and cylinder
COMPRESSION
333222 23 2Defective hydraulic lash adjuster
333223 3 3Loosened spark plugs or defective gasket
333223 3 3Loosened cylinder head bolts or defective gasket
333223 2 2Improper valve seating
333333 3 13Defective valve stem
222223 3 3Worn or broken valve spring
333233 3 12Worn or stuck piston rings, cylinder and piston
222111 12 2Incorrect valve timing
222222Improper engine oil (low viscosity)
76
2-3DIAGNOSTICS
1. Engine Trouble in General

3. Spark Plug
A: REMOVAL AND INSTALLATION
CAUTION:
All spark plugs installed on an engine, must be of the
same heat range.
Spark plug:
CHAMPION: RC10YC4
(Alternate)
NGK: BKR6E-11
NIPPONDENSO: K20PR-U11
1) Remove spark plug cords by pulling boot, not cord itself.
2) Remove spark plugs.
3) When installing spark plugs on cylinder head, use spark
plug wrench.
Tightening torque (Spark plug):
20.6±2.9 N⋅m (2.10±0.30 kg-m, 15.19±2.14 ft-lb)
CAUTION:
The above torque should be only applied to new spark
plugs without oil on their threads.
In case their threads are lubricated, the torque should
be reduced by approximately 1/3 of the specified
torque in order to avoid their over-stressing.
4) Connect spark plug cords.
G6M0086
B: INSPECTION
Check electrodes and inner and outer porcelain of plugs,
noting the type of deposits and the degree of electrode
erosion.
G6M0087
1) Normal
Brown to grayish-tan deposits and slight electrode wear
indicate correct spark plug heat range.
22
6-1SERVICE PROCEDURE
3. Spark Plug

G6M0088
2) Carbon fouled
Dry fluffy carbon deposits on insulator and electrode are
mostly caused by slow speed driving in city, weak ignition,
too rich fuel mixture, dirty air cleaner, etc.
It is advisable to replace with plugs having hotter heat
range.
G6M0089
3) Oil fouled
Wet black deposits show excessive oil entrance into com-
bustion chamber through worn rings and pistons or exces-
sive clearance between valve guides and stems. If same
condition remains after repair, use a hotter plug.
G6M0090
4) Overheating
White or light gray insulator with black or gray brown spots
and bluish burnt electrodes indicate engine overheating.
Moreover, the appearance results from incorrect ignition
timing, loose spark plugs, wrong selection of fuel, hotter
range plug, etc. It is advisable to replace with plugs having
colder heat range.
G6M0091
C: CLEANING AND REGAPPING
Clean spark plugs in a sand blast type cleaner.
Avoid excessive blasting. Clean and remove carbon or
oxide deposits, but do not wear away porcelain.
If deposits are too stubborn, discard plugs.
After cleaning spark plugs, recondition firing surface of
electrodes with file. Then correct the spark plug gap using
a gap gauge.
Spark plug gap: L
1.0—1.1 mm (0.039—0.043 in)
B6M0160
4. Ignition Coil
A: REMOVAL AND INSTALLATION
1) Disconnect battery ground cable.
2) Disconnect connector from ignition coil.
3) Remove ignition coil.
4) Installation is in the reverse order of removal.
CAUTION:
Be sure to connect wires to their proper positions.
Failure to do so will damage unit.
23
6-1SERVICE PROCEDURE
3. Spark Plug - 4. Ignition Coil

G6M0088
2) Carbon fouled
Dry fluffy carbon deposits on insulator and electrode are
mostly caused by slow speed driving in city, weak ignition,
too rich fuel mixture, dirty air cleaner, etc.
It is advisable to replace with plugs having hotter heat
range.
G6M0089
3) Oil fouled
Wet black deposits show excessive oil entrance into com-
bustion chamber through worn rings and pistons or exces-
sive clearance between valve guides and stems. If same
condition remains after repair, use a hotter plug.
G6M0090
4) Overheating
White or light gray insulator with black or gray brown spots
and bluish burnt electrodes indicate engine overheating.
Moreover, the appearance results from incorrect ignition
timing, loose spark plugs, wrong selection of fuel, hotter
range plug, etc. It is advisable to replace with plugs having
colder heat range.
G6M0091
C: CLEANING AND REGAPPING
Clean spark plugs in a sand blast type cleaner.
Avoid excessive blasting. Clean and remove carbon or
oxide deposits, but do not wear away porcelain.
If deposits are too stubborn, discard plugs.
After cleaning spark plugs, recondition firing surface of
electrodes with file. Then correct the spark plug gap using
a gap gauge.
Spark plug gap: L
1.0—1.1 mm (0.039—0.043 in)
B6M0160
4. Ignition Coil
A: REMOVAL AND INSTALLATION
1) Disconnect battery ground cable.
2) Disconnect connector from ignition coil.
3) Remove ignition coil.
4) Installation is in the reverse order of removal.
CAUTION:
Be sure to connect wires to their proper positions.
Failure to do so will damage unit.
23
6-1SERVICE PROCEDURE
3. Spark Plug - 4. Ignition Coil

B: INSPECTION
1. BATTERY
1) External parts
Check for the existence of dirt or cracks on the battery
case, top cover, vent plugs, and terminal posts. If
necessary, clean with water and wipe with a dry cloth.
Apply a thin coat of grease on the terminal posts to prevent
corrosion.
2) Electrolyte level
Check the electrolyte level in each cell. If the level is below
MIN LEVEL, bring the level to MAX LEVEL by pouring dis-
tilled water into the battery cell. Do not fill beyond MAX
LEVEL.
WARNING:

Electrolyte has toxicity; be careful handling the
fluid.

Avoid contact with skin, eyes or clothing. Especially
at contact with eyes, blush with water for 15 minutes
and get prompt medical attention.

Batteries produce explosive gasses. Keep sparks,
flame, cigarettes away.

Ventilate when charging or using in enclosed space.

For safety, in case an explosion does occur, wear
eye protection or shield your eyes when working near
any battery. Never lean over a battery.

Do not let battery fluid contact eyes, skin, fabrics, or
paint-work because battery fluid is corrosive acid.

To lessen the risk of sparks, remove rings, metal
watch-bands, and other metal jewelry. Never allow
metal tools to contact the positive battery terminal and
anything connected to it while you are at the same time
in contact with any other metallic portion of the vehicle
because a short circuit will be caused.
5
6-2SERVICE PROCEDURE
2. Battery

4
CHECK MISFIRE SYMPTOM.
NOTE:

Perform diagnosis according to the items listed below.

Use the MAX. misfire rate values read in step 2-4).
DTC MAX. misfire rate Next
Only one cylinder—Go to step1.
P0301 and P0302 Both rate are at 100 %, or more. Go to step
2.
P0303 and P0304 Both rate are at 100 %, or more. Go to step
3.
P0301 and P0303 Both rate are at 100 %, or more. Go to step
4.
P0302 and P0304 Both rate are at 100 %, or more. Go to step
5.
Others—Go to step
6.
1ONLY ONE CYLINDER
: Check the following items for that cylinder.

Spark plug

Spark plug cord

Fuel injector

Compression ratio

2GROUP OF #1 AND #2 CYLINDERS
: Check the following items for #1 and #2 cyl-
inders.

Spark plugs

Fuel injectors
NOTE:
If no abnormal is discovered, check for“9. F: IGNITION
SYSTEM”of #1 and #2 cylinders side.

3GROUP OF #3 AND #4 CYLINDERS
: Check the following items for #3 and #4 cyl-
inders.

Spark plugs

Fuel injectors
NOTE:
If no abnormal is discovered, check for“9. F: IGNITION
SYSTEM”of #3 and #4 cylinders side.

4GROUP OF #1 AND #3 CYLINDERS
: Check the following items for #1 and #3 cyl-
inders.

Spark plugs

Fuel injectors

Skipping timing belt teeth
215
2-7ON-BOARD DIAGNOSTICS II SYSTEM
11. Diagnostics Chart with Trouble Code