1996 SUBARU LEGACY Fuel system

1. Engine Trouble in General
Numbers shown in the chart refer to the possibility of reason for the
trouble in order (“Very often”to“Rarely”)
1—Very often
2—Sometimes
3—Rarely
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.
POSSIBLE CAUSE
STARTER
2Defective battery-to-starter harness
3Defective starter switch
3Defective inhibitor switch
23Defective starter
BATTERY
1Poor terminal connection
1Run-down battery
2Defective charging system
1111111111 1Fuel injection system Diagnostics II System.>
75
2-3bDIAGNOSTICS
1. Engine Trouble in General

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
2-3bDIAGNOSTICS
1. Engine Trouble in General

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.
LUBRICATION SYSTEM
22 3 3Incorrect oil pressure
2Loosened oil pump attaching bolts and defective
gasket
2Defective oil filter seal
2Defective crankshaft oil seal
32Defective rocker cover gasket
2Loosened oil drain plug or defective gasket
2Loosened oil pan fitting bolts or defective oil pan
COOLING SYSTEM
33221Overheating
333Over cooling
OTHERS
113 3Malfunction of Evaporative Emission Control
System
21Stuck or damaged throttle valve
322 2Accelerator cable out of adjustment
77
2-3bDIAGNOSTICS
1. Engine Trouble in General

If noise still exists, conduct diagnostics procedures in
accordance with the following table.
CAUTION:
Do not disconnect spark plug cord while engine is run-
ning.
Type of sound Condition Possible cause
Regular clicking soundSound increases as engine
speed increases.Valve mechanism is defective.
Broken lash adjuster
Worn camshaft
Broken valve spring
Worn valve lifter hole
Heavy and dull clankOil pressure is low.Worn crankshaft main bearing
Worn connecting rod bearing (big end)
Oil pressure is normal.Loose flywheel mounting bolts
Damaged engine mounting
High-pitched clank
(Spark knock)Sound is noticeable when
accelerating with an overload.Ignition timing advanced
Accumulation of carbon inside combustion chamber
Wrong spark plug
Improper gasoline
Clank when engine speed is
medium (1,000 to 2,000 rpm).Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn crankshaft main bearing
Worn bearing at crankshaft end of connecting rod
Knocking sound when engine
is operating under idling speed
and engine is warm.Sound is reduced when fuel
injector connector of noisy
cylinder is disconnected.
(NOTE*)Worn cylinder liner and piston ring
Broken or stuck piston ring
Worn piston pin and hole at piston end of connecting rod
Sound is not reduced if each
fuel injector connector is
disconnected in turn. (NOTE*)Unusually worn valve lifter
Worn cam gear
Worn camshaft journal bore in crankcase
Squeaky sound—Insufficient generator lubrication
Rubbing sound—Defective generator brush and rotor contact
Gear scream when starting
engine—Defective ignition starter switch
Worn gear and starter pinion
Sound like polishing glass with
a dry cloth—Loose drive belt
Defective engine coolant pump shaft
Hissing sound—Loss of compression
Air leakage in air intake system, hoses, connections or
manifolds
Timing belt noise—Loose timing belt
Belt contacting case/adjacent part
NOTE*:
When disconnecting fuel injector connector, Malfunction Indicator Light (CHECK ENGINE light) illuminates and trouble code is stored in
ECM memory.
Therefore, carry out the CLEAR MEMORY MODE and INSPECTION MODE after connecting fuel injector connector. (Ref. to 2-7 On-Board
Diagnostics II System.)
79
2-3bDIAGNOSTICS
2. Engine Noise

1. Engine Cooling System
Trouble Possible cause Corrective action
Over-heatinga. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt Repair or replace timing belt tensioner.
c. Oil on drive belt Replace.
d. Malfunction of thermostat Replace.
e. Malfunction of engine coolant pump Replace.
f. Clogged engine coolant passage Clean.
g. Improper ignition timingInspect and repair ignition control system.

h. Clogged or leaking radiator Clean or repair, or replace.
i. Improper engine oil in engine coolant Replace engine coolant.
j. Air/fuel mixture ratio too leanInspect and repair fuel injection system.

k. Excessive back pressure in exhaust system Clean or replace.
l. Insufficient clearance between piston and cylinder Adjust or replace.
m. Slipping clutch Repair or replace.
n. Dragging brake Adjust.
o. Improper transmission oil Replace.
p. Defective thermostat Replace.
q. Malfunction of electric fanInspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-coolinga. Atmospheric temperature extremely low Partly cover radiator front area.
b. Defective thermostat Replace.
Engine coolant
leaks.a. Loosened or damaged connecting units on hoses Repair or replace.
b. Leakage from engine coolant pump Replace.
c. Leakage from engine coolant pipe Repair or replace.
d. Leakage around cylinder head gasket Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crankcase Repair or replace.
f. Damaged or cracked thermostat case Repair or replace.
g. Leakage from radiator Repair or replace.
Noisea. Defective drive belt Replace.
b. Defective radiator fan Replace.
c. Defective engine coolant pump bearing Replace engine coolant pump.
d. Defective engine coolant pump mechanical seal Replace engine coolant pump.
20
2-5DIAGNOSTICS
1. Engine Cooling System

FUEL INJECTION SYSTEM2-7
Page
C COMPONENT PARTS....................................................................................2
1. Intake Manifold.........................................................................................2
2. Air Intake System.....................................................................................3
3. Air Cleaner ...............................................................................................4
W SERVICE PROCEDURE...............................................................................5
1. Air Cleaner and Air Intake Duct ...............................................................5
2. Mass Air Flow Sensor ..............................................................................6
3. Throttle Body............................................................................................7
4. Intake Manifold.........................................................................................8
5. Engine Coolant Temperature Sensor ....................................................18
6. Crankshaft Position Sensor ...................................................................18
7. Front Oxygen Sensor.............................................................................19
8. Rear Oxygen Sensor .............................................................................21
9. Throttle Position Sensor ........................................................................24
10. Camshaft Position Sensor .....................................................................25
11. Pressure Sensor (AT model)..................................................................25
12. Idle Air Control Solenoid Valve ..............................................................26
13. Pressure Sources Switching Solenoid Valve (AT model) ......................27
14. Fuel Injector ...........................................................................................28
15. Engine Control Module ..........................................................................28
16. Main Relay .............................................................................................30
17. Fuel Pump Relay ...................................................................................31

FUEL SYSTEM2-8
Page
S SPECIFICATIONS AND SERVICE DATA....................................................2
1. Fuel System .............................................................................................2
C COMPONENT PARTS..................................................................................3
1. Fuel Tank ................................................................................................3
2. Fuel Line ..................................................................................................7
W SERVICE PROCEDURE...........................................................................10
1. Precautions ...........................................................................................10
2. On-Car Services ....................................................................................12
3. Fuel Tank ...............................................................................................13
4. Fuel Filler Pipe .......................................................................................16
5. Fuel Filter ..............................................................................................18
6. Fuel Pump ............................................................................................19
7. Fuel Meter Unit .....................................................................................20
8. Fuel Delivery, Return and Evaporation Lines ........................................22
9. Roll Over Valve ......................................................................................25
10. Fuel Sub Meter Unit (AWD model only) ................................................25
11. Fuel Cut Valve (AWD model only) .........................................................26
K DIAGNOSTICS...........................................................................................27
1. Fuel System ...........................................................................................27

1. Fuel System
A: SPECIFICATIONS
Fuel tankCapacity 60
(15.9 US gal, 13.2 Imp gal)
Location Under rear seat
Fuel pumpType Impeller
Discharge pressure 250.1 kPa (2.55 kg/cm
2, 36.3 psi)
Discharge flowAWD: More than 80
(21.1 US gal, 17.6 Imp gal)/h
FWD: More than 65
(17.2 US gal, 14.3 Imp gal)/h
[12 V at 300 kPa (3.06 kg/cm
2, 43.5 psi)]
Fuel filterCartridge type
2
2-8SPECIFICATIONS AND SERVICE DATA
1. Fuel System