Engine Controls - System/component Tests Subaru Justy I рестайлинг

INTRODUCTION

Before testing separate components or systems, perform procedures in BASIC TESTING article in the ENGINE PERFORMANCE Section. Since many computer controlled and monitored components set a trouble code if they malfunction, also perform procedures in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Note. Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.

HIGH BOOST PRESSURE

If turbocharger fails, excessive boost pressures can cause engine knock and overheating. Check wastegate operation, electrical circuits between wastegate duty solenoid and ECU and ECU problems.

LOW BOOST PRESSURE

Low boost pressure can cause the following: lack of power, poor acceleration, and increased fuel consumption. Check for leaks in the intake and exhaust system, incorrect ignition timing, electrical circuits between wastegate duty solenoid and ECU and ECU problems.

OIL LEAKS

1. Worn turbocharger oil seals can cause excessive oil consumption and White smoke from the exhaust. Remove center exhaust pipe and examine the turbocharger from the exhaust side. If there is excessive carbon deposits on the turbine exhaust side, oil is leaking from the turbine.
2. The turbocharger is not necessarily defective when oil is present on the blower side. Oil most likely has come from oil vapors contained in blow-by gases present in the intake system or defective PCV system.
3. If intake side contains oil and a rattle is present, remove the turbocharger. Check the end play and side play.

TURBOCHARGER COMPONENT TESTING

Note. No provision has been made for turbocharger disassembly or adjustment. Replace turbocharger if found to be defective.

BOOST PRESSURE TESTING

1. Disconnect wastegate duty solenoid connector. Engine must be at normal operating temperature. Disconnect rubber hose from pressure switch. Using a "T" fitting, connect an air pressure gauge. Use enough hose so that gauge may be carried inside passenger compartment.
2. Boost pressure should be checked at 2400 RPM with a wide open throttle. Normal pressure is 14.5-17 in Hg. (7.3-8.3 psi). Reconnect wastegate duty solenoid.
3. If boost pressure is too high, check the rubber hose that connects the intake manifold to the wastegate valve. Replace if defective. If wastegate valve is not operating and remains closed, replace the turbocharger. If boost pressure is too low, replace the turbocharger.

WASTEGATE DUTY SOLENOID TESTING

Disconnect wastegate duty solenoid connector. Using an ohmmeter, measure solenoid resistance. If resistance is not 17-21 ohms, replace solenoid. Check solenoid terminals for a short to ground. Also see TESTS W/CODES article in the ENGINE PERFORMANCE Section.

END PLAY & SIDE PLAY TESTING

The maximum end play on the turbine shaft is .0035" (.09 mm). Maximum side play is .0067" (.17 mm). Side play is checked by moving intake and exhaust side of shaft at the same time.

A/C SWITCH TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

AIRFLOW METER TESTING

Remove rubber cover from electrical connector on airflow meter. Leave connector connected. Connect volt/ohmmeter between terminals and record readings. See AIRFLOW METER SPECIFICATIONS table. If readings are not to specifications, check electrical wiring. If wiring is okay, replace airflow sensor.

Note. DO NOT start engine unless specified. Place the ignition switch in the OFF or ON position as indicated.

Note. Airflow meter test specifications for Justy not available from manufacturer.

AIRFLOW METER SPECIFICATIONS

ATMOSPHERIC PRESSURE SENSOR (JUSTY & LEGACY) TESTING

See HIGH ALTITUDE COMPENSATOR in this article.

BLOWER MOTOR SWITCH (JUSTY) TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

CLUTCH SWITCH (JUSTY) TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

COOLANT TEMPERATURE SENSOR TESTING

Disconnect coolant temperature sensor connector. Connect ohmmeter leads between sensor terminals. See COOLANT TEMPERATURE SENSOR RESISTANCE table.

COOLANT TEMPERATURE SENSOR RESISTANCE

CRANK ANGLE SENSOR TESTING

For testing information, see TESTS W/CODES article in the ENGINE PERFORMANCE Section.

EGR TEMPERATURE SENSOR (LOYALE - CALIF.) TESTING

See TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

ELECTRICAL LOAD SENSORS (JUSTY) TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

LIGHT SWITCH (JUSTY) TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

OXYGEN SENSOR TESTING

For testing procedures, see appropriate trouble code(s) for rich or lean running in TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

P/N SWITCH (EXCEPT JUSTY) TESTING

See TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section and test switch and circuits as necessary.

STARTER SWITCH TESTING

See WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section and test switch and related circuits as necessary.

THROTTLE POSITION SENSOR (OR SWITCH) TESTING

For testing and adjustments, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

PRESSURE SENSOR TESTING

For testing, see TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

VEHICLE SPEED SENSOR TESTING

For testing, see TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

EGR SOLENOID

See EGR SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in this article and TESTS W/CODES article in the ENGINE PERFORMANCE Section for appropriate trouble code.

FLOAT BOWL CONTROL SOLENOID

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in this article.

FUEL PUMP RELAY

For testing procedures, see BASIC TESTING and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

HIGH ALTITUDE COMPENSATOR SOLENOIDS

See HAC SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in this article and TESTS W/CODES article in the ENGINE PERFORMANCE Section for appropriate trouble code.

MAIN RELAY

For testing procedures see BASIC TESTING and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

PURGE CONTROL SOLENOID

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in this article.

VACUUM LINE CONTROL (VLC) SOLENOID (JUSTY CARBURETED)

See HAC SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in this article and TESTS W/CODES article in the ENGINE PERFORMANCE Section for appropriate trouble code(s).

See EGR SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in this article and TESTS W/CODES article in the ENGINE PERFORMANCE Section for appropriate trouble code.

FUEL INJECTOR(S)

1. Connect tachometer to engine. Start engine and run at idle. Remove harness connector from injectors one at a time. Engine idle speed should drop 100-300 RPM as each injector is disconnected. If engine idle speed does not drop, check the wiring connector, injector resistance or injection signal from the computer.
2. Disconnect electrical connector from each injector. Measure injector resistance. See INJECTOR RESISTANCE SPECIFICATIONS table. If injector is not to specification, replace injector.

INJECTOR RESISTANCE SPECIFICATIONS

FUEL INJECTOR RESISTORS

Disconnect resistor block. Measure resistance between terminal "W" and "B". If reading is not 5.8-6.5 ohms, replace resistor block.

KICKDOWN RELAY CONTROL (LOYALE TBI)

For testing procedures, see TESTS W/CODES article in the ENGINE PERFORMANCE Section.

For testing procedures on all models, see BASIC TESTING and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

For testing procedures see BASIC TESTING and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

See FUEL EVAPORATION under EMISSION SYSTEMS & SUB-SYSTEMS in this article and TESTS W/CODES article in the ENGINE PERFORMANCE Section for appropriate trouble code.

FUEL DELIVERY

Note. For fuel system pressure testing, see BASIC TESTING article in the ENGINE PERFORMANCE Section.

DUTY SOLENOID (JUSTY)

Disconnect harness and measure resistance between solenoid terminals. Ensure resistance is 10-100 ohms. If not, replace solenoid(s). Also see appropriate trouble code(s) in BASIC TESTING article in the ENGINE PERFORMANCE Section.

FEEDBACK SYSTEM

Manufacturer recommends complete inspection of self-diagnostic system be performed. This would also include checking mechanical condition of engine, available fuel to carburetor or injectors and ignition. Repair or replace components as required and test drive vehicle.

SYSTEM INSPECTION

Ensure self-diagnostic system is checked for any trouble codes. See appropriate article in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

AUXILIARY AIR VALVE (1.2L PFI & 1.8L)

1. With engine running, pinch hose between Auxiliary Air Valve (AAV) and intake manifold. Engine speed should drop (about 100 RPM with engine warm, more with engine cold). Release hose. Ensure engine speed returns to previous speed.
2. If RPM is not as specified, turn ignition off. Check AAV resistance. If reading is either zero or infinity, replace AAV. Check AAV solenoid for any short to ground. If present, replace solenoid.
3. Check for voltage at harness connector. Ensure 12 volts are available at Blue wire of AAV electrical connector. If not, check main relay, fuses and power source.

BY-PASS AIR CONTROL VALVE (2.7L PFI)

1. Disconnect By-Pass Air Control Valve (BACV) harness connector. Connect ohmmeter leads between terminals No. 1 (Yellow/Red wire) and No. 2 (Black/White wire). Resistance should be 9.5-11.5 ohms.
2. Measure resistance between terminals No. 2 (Black/White wire) and No. 3 (Yellow/Blue wire). Resistance should be 8.5-10.5 ohms. Ensure terminals are not shorted to ground. If BACV does not test as described, replace BACV.

BY-PASS AIR CONTROL VALVE (TBI)

1. With engine running, disconnect electrical connector. Engine speed should drop (a little with engine warm, a lot with engine cold). Reconnect electrical connector. Ensure engine speed returns to previous speed.
2. If not, turn engine off. Turn ignition switch to ON position. Ensure 10-12 volts are available at Black/White wire of air control valve electrical connector.
3. Turn ignition off. Ensure resistance of Air Control Valve (ACV) is 7.3-13 ohms at -4 to 176°F (-20 to 80°C). If not, replace ACV. Check ACV solenoid for any short to ground. If present, replace ACV.
4. Attach electrical connector to ACV. Disconnect connector at ECU. Turn ignition on. Ensure 10-12 volts are present at terminal No. 45 (Green/Red wire) of ECU. If not, check harness between ACV and ECU.
5. Turn ignition off and reconnect ECU connector. Turn ignition on. Backprobe terminal No. 45 (Green/Red wire) of ECU. There should be one volt or less for about one minute after ignition switch is turned to ON position. After one minute, there should be at least 10 volts. If not, check for a bad ground, problem with ECU circuits (sensors) or ECU.

DASHPOT (JUSTY PFI & XT)

To check and adjust dashpot, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

FAST IDLE & IDLE-UP CONTROL DEVICE (JUSTY PFI)

Using a hand vacuum pump, check to see if control device will hold vacuum. On models equipped with A/C, ensure idle speed increases when A/C is turned on. On models without A/C, idle speed should increase when headlights, rear defogger or heater blower is turned on. (Scheme 14)

Scheme 14

IDLE COMPENSATOR (JUSTY CARBURETED)

Remove top of air cleaner. With engine running, apply a source of heated air to warm up idle compensator. Ensure idle compensator opens and idle speeds up. Allow idle compensator to cool (should close). If idle compensator does not test as described, replace.

IDLE-UP SOLENOID (JUSTY)

Disconnect harness and measure resistance between solenoid terminals. Ensure resistance is 33-40 ohms. (Scheme 15) If not, replace solenoid. Also see appropriate trouble code(s) in TESTS W/CODES article in the ENGINE PERFORMANCE Section.

Scheme 15

IGNITION SYSTEM

Note. For basic ignition checks (coil, wires, crank angle sensor), see TESTS W/CODES article in the ENGINE PERFORMANCE Section.

ELECTRONIC ADVANCE

For testing, see ADJUSTMENTS article in the ENGINE PERFORMANCE Section.

KNOCK SENSOR (LEGACY, LOYALE TURBO & XT6)

For testing, see TESTS W/CODES and WIRING DIAGRAMS articles in the ENGINE PERFORMANCE Section.

Suction Valve

1. Blow air through suction valve air inlet section. Air should flow smoothly through to valve outlet. (Scheme 16)and (Scheme 17). If air does not flow through smoothly, reed valve is stuck closed. Replace reed valve.
2. Blow air through valve outlet. If air flows out inlet, reed valve is broken or stuck open. Replace reed valve.
3. Open suction valve. Inspect gasket, inlet case and outlet case for damage (cracks). Clean reed valve with gasoline and inspect for waves, cracks or dents in reed valve seat. Inspect for broken or cracked point of reed valve, or rusted stopper. Replace as required. (Scheme 18)

Scheme 16

Scheme 17

Scheme 18

EGR System (Justy Carbureted & Loyale TBI)

1. Apply about 8 in. Hg to EGR valve with hand vacuum pump. With engine warmed up, either rough idling or engine stall should occur. (Scheme 19)and (Scheme 20).
2. If engine idle does not change, check EGR pipe and gas passages for clogging and leaks. Clean or replace if necessary. When cleaning, inspect exhaust gas inlet to intake manifold for presence of deposits. Inspect EGR inlet pipe for exhaust deposits.

Scheme 19

Scheme 20

EGR Valve

1. Look through opening in EGR valve body. Warm engine to normal operating temperature. Increase engine speed and check if valve shaft moves when engine reaches 3500-4000 RPM under no-load condition.
2. If shaft does not move, remove valve and manually check valve movement. If valve appears okay, check vacuum lines for leaks. If valve does not operate, clean or replace. NOTE: When cleaning EGR valve, DO NOT wash in solvent or degreaser, or permanent damage to the valve diaphragm will result.
3. Depress valve diaphragm and inspect valve seat area. Inspect valve inlet and outlet for deposits and clean as necessary. Blow clean with compressed air. Recheck valve operation by applying 8 in. Hg with a hand vacuum pump. Install unit using a new gasket.

EGR Solenoid Valve (Justy Carbureted & Loyale TBI)

1. Remove connector from solenoid valve. Measure resistance of solenoid valve. Resistance should be 33-40 ohms. If resistance is not 33-40 ohms, replace solenoid valve.
2. Measure resistance between solenoid valve terminal leads and body ground. If solenoid is shorted, replace solenoid valve.
3. Check vacuum passage for opening and closing operation. When EGR solenoid is not energized, passage between "A" and "B" should be closed and passage between "B" and "C" should be open. (Scheme 21) When solenoid is energized, passage between "A" and "B" should be open and passage between "B" and "C" should be closed.

Scheme 21

FUEL EVAPORATION

System Test

Remove fuel filler cap. Disconnect vent hose between charcoal canister and fuel tank. Blow air toward canister. Ensure air flows freely into canister. Blow air toward fuel tank. Ensure air flows into tank with a slight resistance from 2-way valve. (Scheme 22)- (Scheme 27).

Scheme 22

Scheme 23

Scheme 24

Scheme 25

Scheme 26

Scheme 27

Charcoal Canister

1. Remove vacuum hose from canister purge vent port (main purge vent on turbo). (Scheme 28) Blow air into canister purge vent port. Airflow will be blocked if valve is operating properly.
2. Remove hoses from canister's fuel tank and carburetor ports. Blow air into each port. Check that air flows into canister.
3. On Turbo models, remove secondary purge hose. Blow into hose. Air should flow with a slight resistance.

Scheme 28

2-Way Valve

Remove valve from hoses. Mark hoses for reinstallation. Blow air into each valve port. Ensure air flows through valve with light resistance. Visually inspect valve for cracks.

Bowl Vent Or Purge Control Solenoid Valve

1. Connect ohmmeter leads between terminals of solenoid. See BOWL VENT OR PURGE CONTROL SOLENOID VALVE RESISTANCE table. If resistance is not as specified, replace solenoid valve.
2. Using an ohmmeter, ensure windings are not grounded. Apply battery voltage to valve terminals. Ensure passage opens and closes as voltage is applied and removed. (Scheme 29)

BOWL VENT OR PURGE CONTROL SOLENOID VALVE RESISTANCE

Scheme 29

Atmospheric Pressure Sensor (Justy PFI & Legacy)

Atmospheric pressure sensor is located in ECU. If appropriate trouble code appears, replace ECU.

High Altitude Compensator Solenoids (Justy Carbureted)

1. Connect ohmmeter leads between terminals of Black/White and White/Red wires of solenoid. If resistance is not 33-40 ohms, replace solenoid valve.
2. Ensure windings are not grounded. Apply battery voltage to valve terminals. Ensure vacuum passage opens and closes as voltage is applied and removed.
3. When solenoid is not energized, passage between "A" and "B" should be closed. (Scheme 30) When solenoid is energized, passage between "A" and "B" should be open. If solenoid valve does not operate properly, replace solenoid valve.

Scheme 30

Vacuum Line Control Solenoid Valve (Justy Carbureted)

1. Connect ohmmeter leads between terminals of solenoid. If resistance is not 10-100 ohms, replace solenoid valve.
2. Using an ohmmeter, ensure windings are not grounded. Apply battery voltage to valve terminals. Ensure passage opens and closes as voltage is applied and removed.
3. When solenoid is not energized, passage between "A" and "B" should be closed and open between "B" and "C". (Scheme 30) When solenoid is energized, passage between "A" and "B" should be open and closed between "B" and "C". If solenoid valve does not operate properly, replace solenoid valve.

PCV

Note. For information on PCV systems (Scheme 31)- (Scheme 35).

Scheme 31

Scheme 32

Scheme 33

Scheme 34

Scheme 35

Air Control Diaphragm & Valve

1. In warm weather, it may be difficult to find a malfunction in hot air control system. In cold weather, vacuum leaks or faulty air control valve will result in engine stalling or hesitation, increased fuel consumption and/or lack of power.
2. Check vacuum hoses for cracks and proper connections. Inspect air control diaphragm (vacuum motor) with engine stopped. (Scheme 36)
3. Disconnect vacuum hose from air control diaphragm. Apply vacuum to diaphragm. Valve should rise to open position (hot air inlet uncovered, fresh air inlet blocked).
4. If diaphragm does not hold vacuum, replace it. With valve in open position, pinch hose to trap vacuum. Valve should remain open for at least 30 seconds. If valve closes too soon, replace air control diaphragm.

Scheme 36

Note. Engine must be cold before performing following test. Check hoses, air control diaphragm and valve first.

Temperature Sensor Valve

1. Start engine, allow to idle. Observe position of air control valve. Valve should be open (hot air inlet uncovered, fresh air inlet blocked).
2. Continue to observe valve as engine warms up. Air control valve should gradually move to closed position (hot air inlet blocked). If valve does not move to closed position, replace temperature sensor valve assembly.