Engine Controls - Adjustments Subaru SVX I

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition system, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. All models except Justy are equipped with hydraulic lash adjusters. No adjustment is required for those models.

Justy

1. Position piston to cylinder to be adjusted at Top Dead Center (TDC) of compression stroke. Insert thickness gauge between valve and valve rocker arm to measure valve clearance. Adjust valves when engine is cold. Use Valve Clearance Adjuster (498767000) and adjust to specification. See «3-CYLINDER VALVE CLEARANCE SPECIFICATIONS»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table.
2. After adjustment, rotate crankshaft several turns and recheck valve clearance. Readjust if necessary.

3-CYLINDER VALVE CLEARANCE SPECIFICATIONS

1. Warm engine to normal operating temperature. Set transmission in Neutral. Turn off all accessories. Connect test mode connector. (Scheme 1)
2. Connect timing light. Start engine. Observe timing marks located on crankshaft pulley. Refer to the «3-CYLINDER IGNITION TIMING SPECIFICATIONS»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If necessary, loosen distributor hold-down bolt and adjust ignition timing by rotating distributor. After adjusting ignition timing, tighten distributor hold-down bolt.

3-CYLINDER IGNITION TIMING SPECIFICATIONS

Scheme 1

Impreza & Legacy

1. Ensure engine is at normal operating temperature and idle speed is correct. Set transaxle in Neutral (M/T) or Park (A/T) position. Connect timing light to No. 1 spark plug wire.
2. Observe timing marks, located on crankshaft pulley. See the «4-CYLINDER IGNITION TIMING SPECIFICATIONS»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If timing is not as specified, check self-diagnostic system for trouble codes. Repair as necessary. See appropriate G - TESTS W/ CODES article in this section.

Loyale

1. Ensure engine is at normal operating temperature and idle speed is correct. Set transaxle in Park (A/T) or Neutral (M/T) position.
2. Ensure throttle valve is closed and throttle position sensor is correctly adjusted. Connect 2 test mode connectors. (Scheme 2) NOTE: When checking timing, CHECK ENGINE warning light will come on. This is not an indication of a problem. Ignition timing cannot be set if idle contacts in TPS are open and test mode connectors are not connected.
3. Observe timing marks, located on crankshaft pulley. See the «4-CYLINDER IGNITION TIMING SPECIFICATIONS»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If necessary, adjust ignition timing by loosening distributor hold-down bolt and rotating distributor. After adjusting ignition timing, unplug test mode connectors.

Scheme 2

4-CYLINDER IGNITION TIMING SPECIFICATIONS

SVX

Warm engine to normal operating temperature. Turn A/C off. Connect Subaru Test Mode Monitor to test mode monitor connector, located under left side of dash. (Scheme 3) Using test mode monitor, select MODE 07 to determine ignition timing. Refer to the 6-CYLINDER IGNITION TIMING SPECIFICATION table. If ignition timing is not as specified, check self-diagnostic system for trouble codes. Repair as necessary. See appropriate G - TESTS W/ CODES article in this section.

Scheme 3

6-CYLINDER IGNITION TIMING SPECIFICATION

IDLE SPEED & MIXTURE

Note. Idle mixture is electronically controlled; adjustment procedure is not available from manufacturer.

COLD (FAST) IDLE

Note. Fast idle on TBI engines is controlled by air control valve. On PFI engines, fast idle is controlled by auxiliary air valve. Adjustment is not necessary on either system.

Justy PFI

1. While slowly returning throttle valve from fully open position, read engine RPM when dashpot lever comes in contact with dashpot.
2. Engine speed should be 2200-2400 RPM when dashpot lever contacts dashpot. If engine speed is not to specification, loosen lock nut and rotate adjuster screw to obtain correct adjustment.

1. Ensure ignition timing is correct. Ensure vacuum hoses, blow-by hoses, rocker arm cover, oil cap, and other components connected to intake system are securely attached.
2. Warm engine and oxygen sensor by operating engine at 2500 RPM for about one minute after engine reaches normal operating temperature. Disconnect and plug canister purge hose at check valve (near intake manifold).
3. Connect both ends of test mode and read memory connectors. (Scheme 1) Set transaxle in Neutral (M/T) or Park (A/T) position. Start engine. Rotate idle speed screw to adjust idle speed to specification. See the «3-CYLINDER IDLE SPEED SPECIFICATIONS»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. (Scheme 4) Unplug both test mode and read memory connector ends.

Scheme 4

3-CYLINDER IDLE SPEED SPECIFICATIONS

3-CYLINDER IDLE MIXTURE

Note. Idle mixture is electronically controlled; adjustment procedure is not available from manufacturer.

Impreza

1. Ensure air filter is clean, vacuum hoses are properly routed, spark plugs are in good condition, and timing is correct. Warm engine to normal operating temperature. Turn ignition off. Connect Select Monitor, following manufacturer's instructions.
2. Start and idle engine. Select MODE F04. Measure idle speed with accessories off, then with A/C on. See «IDLE SPEED SPECIFICATIONS (IMPREZA)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If idle speed is not as specified, check self-diagnostic system for trouble codes. Repair as necessary. See appropriate G - TESTS W/ CODES article in this section.

IDLE SPEED SPECIFICATIONS (IMPREZA)

Legacy

1. Ensure air filter is clean, vacuum hoses are properly routed, and timing is correct. Warm engine to operating temperature. Connect inductive pick-up tachometer to No. 1 spark plug wire. NOTE: Because spark plugs No. 1 and 2 fire simultaneously, some tachometers may register twice actual engine speed.
2. Measure idle speed with all accessories off, then with all accessories on. See the «IDLE SPEED SPECIFICATIONS (LEGACY)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If idle speed is not as specified, check self-diagnostic system for trouble codes. Repair as necessary. See appropriate G - TESTS W/ CODES article in this section.

IDLE SPEED SPECIFICATIONS (LEGACY)

1. Warm engine to normal operating temperature. Turn engine off. Unplug electrical connector for air control valve. Start engine.
2. Rotate idle adjustment screw to adjust idle speed to 500-600 RPM. (Scheme 5) Reconnect wiring for air control valve. Verify idle speed is within specification.

Scheme 5

1. Ensure air filter is clean, vacuum hoses are properly routed, and timing is correct. Warm engine to operating temperature. Connect Subaru Test Mode Monitor to test mode connector. (Scheme 3) Measure engine RPM (MODE F04).
2. Measure idle speed with all accessories off, then with all accessories on. See «IDLE SPEED SPECIFICATIONS (SVX)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. If idle speed is not as specified, check self-diagnostic system for trouble codes. Repair as necessary. See appropriate G - TESTS W/ CODES article in this section.

IDLE SPEED SPECIFICATIONS (SVX)

Justy (PFI)

1. With ignition off, unplug Throttle Position Switch (TPS) connector, located at throttle body. Measure and record resistance between terminals No. 2 and 3 with throttle fully closed, then with throttle fully open. (Scheme 6)
2. If necessary, loosen attaching screws and rotate TPS until correct resistance is obtained. Refer to the «3-CYLINDER THROTTLE POSITION SWITCH RESISTANCE (PFI)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. Replace TPS if resistance cannot be adjusted to specification.

3-CYLINDER THROTTLE POSITION SWITCH RESISTANCE (PFI)

Scheme 6

4-CYLINDER THROTTLE POSITION SENSOR

Note. All testing procedures are performed with engine at normal operating temperature.

1. Turn ignition on. With throttle fully closed, measure and record voltage to ground at specified ECM terminals. Open throttle fully. Repeat voltage measurements. Refer to the «TPS VOLTAGE SPECIFICATIONS (IMPREZA)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. TPS VOLTAGE SPECIFICATIONS (IMPREZA) Terminal Voltage Throttle Closed No. 4 0.4-0.5 No. 11 0 No. 15 4.4-5.5 Throttle Closed No. 4 3.5-4.3 No. 11 0 No. 15 4.4-5.5
2. If necessary, loosen retaining screws and rotate TPS until correct voltages are obtained. Replace TPS if voltage cannot be adjusted to specification.

With engine off, unplug TPS connector, located at throttle body. Measure and record resistance between terminals No. 2 and 3 with throttle fully closed. (Scheme 7) Measure and record resistance between terminals No. 2 and 4 with throttle fully closed, then with throttle fully open. If readings are not as specified, replace throttle position sensor. Refer to the 4-CYLINDER THROTTLE POSITION SENSOR RESISTANCE table.

Scheme 7

1. With ignition off, unplug TPS connector, located at throttle body. Measure and record resistance between terminals "B" and "D". (Scheme 8) Measure and record resistance between terminals "B" and "C" with throttle fully closed, then with throttle fully open.
2. If necessary, loosen retaining screws and rotate TPS until correct resistance is obtained. Refer to the «4-CYLINDER THROTTLE POSITION SENSOR RESISTANCE»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table. Replace TPS if resistance cannot be adjusted to specification.

4-CYLINDER THROTTLE POSITION SENSOR RESISTANCE

6-CYLINDER THROTTLE POSITION SENSOR

Note. All testing procedures are performed with engine at normal operating temperature.

1. With ignition off, unplug TPS electrical connector, located at throttle body. Measure and record resistance between TPS terminals No. 1 and 3 with throttle fully closed. (Scheme 8)
2. Measure and record resistance between terminals No. 2 and 3 with throttle fully closed, then fully open. If readings are not as specified, replace TPS. See «6-CYLINDER THROTTLE POSITION SENSOR RESISTANCE (SVX)»(/subaru/svx/i-1991-1997/remont/adjustments/#engine-controls-adjustments) table.

6-CYLINDER THROTTLE POSITION SENSOR RESISTANCE (SVX)

Scheme 8

See also:
• 3-CYLINDER VALVE CLEARANCE SPECIFICATIONS