Engine Controls - Basic Diagnostic Procedures: Other Mitsubishi Eclipse III

Compression

Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manual for specific instructions.

Disconnect Crankshaft Position (CKP) sensor to disable ignition and injectors. Check engine compression with engine at normal operating temperature, all spark plugs removed and throttle wide open. See COMPRESSION SPECIFICATIONS .

COMPRESSION PRESSURE

Exhaust System Backpressure

The exhaust system can be tested with a vacuum or pressure gauge. If using a pressure gauge, remove front Heated Oxygen Sensor (HO2S). Connect a 0-5 psi pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi, exhaust system or catalytic converter is plugged.

If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port. Start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge indication slowly drops after stabilizing, inspect exhaust system for restriction.

FUEL SYSTEM

Note. Manufacturer does not provide fuel pump maximum pressure or volume specifications.

RELIEVING FUEL PRESSURE

1. On all models except Montero, remove rear seat cushion, remove protector cover and disconnect fuel pump module harness connector. On Montero, fold down second seat, remove upper and lower service covers and disconnect fuel pump module harness connector.
2. Start engine. Let engine run until it stops. Turn ignition off. Reconnect fuel pump module harness connector. Install protector cover and seat cushion.

FUEL PRESSURE

1. Relieve fuel pressure. See «RELIEVING FUEL PRESSURE»(ref-135483-S16350548392002022200000). Disconnect high pressure fuel inlet line at fuel rail. Connect fuel pressure gauge with Adapters (MD998709 and MD998742) between fuel rail and high pressure fuel inlet line. (Scheme 1) Use scan tool to operate fuel pump. Ensure no fuel leaks are present.
2. Start engine and allow it to idle. Measure fuel pressure with vacuum hose connected to fuel pressure regulator. Record fuel pressure reading. See «FUEL PUMP PERFORMANCE»(ref-135483-S08507825862002022200000). Disconnect vacuum hose from fuel pressure regulator and plug vacuum hose end. Record fuel pressure reading. FUEL PUMP PERFORMANCE Application At Idle W/Vacuum - psi (kPa) At Idle W/O Vacuum - psi (kPa) All Models 38 (270) 47-50 (330-350)
3. Race engine several times. Fuel pressure should not drop. Check that fuel pressure is present in fuel return hose by gently squeezing hose while racing engine. If fuel volume is low, fuel pressure in return hose will not be felt.
4. If fuel pressure is lower than specification, fuel pressure drops when racing engine, or no fuel pressure in fuel return hose can be felt, check for clogged fuel filter, faulty fuel pressure regulator or fuel pump delivery pressure.
5. If fuel pressure is greater than specification, check for a faulty fuel pressure regulator or plugged fuel return line. If fuel pressure does not change when vacuum hose to regulator is connected or disconnected, check for a leaking or clogged vacuum hose to fuel pressure regulator, or faulty fuel pressure regulator.
6. Stop engine. Observe fuel pressure reading for 2 minutes. Pressure should hold steady. If pressure drops sharply immediately after engine is stopped, the check valve in fuel pump is stuck open. If fuel pressure gradually drops after engine is stopped, restart engine and bring fuel pressure back up.
7. Stop engine. While observing fuel pressure, squeeze fuel return line closed to check for fuel regulator as source of leak down. Squeeze high pressure fuel inlet line closed to check for fuel pump check valve as source of leak down. Squeeze both lines closed to check for injectors as source of leak down.
8. When fuel pressure test is complete, repeat fuel pressure release procedure before disconnecting fuel pressure gauge. Install NEW "O" ring at end of high pressure fuel inlet line. Connect high pressure fuel inlet line to fuel rail. Tighten bolts to 44 INCH lbs. (5 N.m). Use scan tool to operate fuel pump and check for fuel leaks.

Scheme 1

Diamante, Mirage, Montero & Montero Sport

1. Remove fuel pump relay. See «FUEL PUMP RELAY LOCATION»(ref-135483-S07263026522002022200000). Check continuity between relay terminals No. 2 and 4. (Scheme 11) Continuity should exist.
2. Connect fused jumper wire between battery positive terminal and relay terminal No. 4. Connect second jumper wire between battery negative terminal and fuel pump relay terminal No. 2.
3. With relay energized, continuity should exist between terminals No. 1 and 3. With power source removed, continuity should not exist between terminals No. 1 and 3. If relay does not test as specified, replace fuel pump relay.

Eclipse, Galant & Lancer

1. Remove fuel pump relay No. 2. See «FUEL PUMP RELAY LOCATION»(ref-135483-S07263026522002022200000). Check continuity between relay terminals No. 1 and 4. (Scheme 11) Continuity should exist.
2. Connect fused jumper wire between battery positive terminal and relay terminal No. 1. Connect second jumper wire between battery negative terminal and fuel pump relay terminal No. 4.
3. With relay energized, continuity should exist between terminals No. 2 and 3. With power source removed, continuity should not exist between terminals No. 2 and 3. If relay does not test as specified, replace fuel pump relay.

FUEL PUMP RELAY LOCATION

Scheme 2

Scheme 3

Scheme 4

Scheme 5

Scheme 6

Scheme 7

Scheme 8

Scheme 9

Scheme 10

Scheme 11

IGNITION CHECKS

Note. Perform all circuit tests with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless stated otherwise in test procedure.

MFI relay switches power to vehicle sensors and actuators including Volume Airflow (VAF) sensor, Crankshaft Position (CKP) sensor, Camshaft Position (CMP) sensor, Idle Air Control (IAC) motor and fuel injectors. Relay failure will cause a no-start condition.

1. Remove MFI relay. See «MULTIPORT FUEL INJECTION RELAY LOCATION»(ref-135483-S17335515192003043000000). Check continuity between relay terminals No. 2 and 4. (Scheme 11) Continuity should exist.
2. Connect jumper wire between battery positive terminal and relay terminal No. 4. Connect second jumper wire between battery negative terminal and MFI relay terminal No. 2.
3. With relay energized, continuity should exist between terminals No. 1 and 3. With power source removed, continuity should not exist between terminals No. 1 and 3. If relay does not test as specified, replace MFI relay.

MFI relay switches power to vehicle sensors and actuators including Volume Airflow (VAF) sensor, Crankshaft Position (CKP) sensor, Camshaft Position (CMP) sensor, Idle Air Control (IAC) motor and fuel injectors. Relay failure will cause a no-start condition.

1. Remove MFI relay. See «MULTIPORT FUEL INJECTION RELAY LOCATION»(ref-135483-S17335515192003043000000). Check continuity between relay terminals No. 2 and 3. (Scheme 11) Continuity should exist.
2. Connect jumper wire between battery positive terminal and relay terminal No. 2. Connect second jumper wire between battery negative terminal and MFI relay terminal No. 3.
3. With relay energized, continuity should exist between terminals No. 1 and 4. With power source removed, continuity should not exist between terminals No. 1 and 4. If relay does not test as specified, replace MFI relay.

MULTIPORT FUEL INJECTION RELAY LOCATION

SPARK

Check for spark at coil wire (if applicable) and at each spark plug wire using a high output spark tester. Check spark plug wire resistance on suspect wires. Wire resistance should not exceed 19,000 ohms.

CAMSHAFT POSITION (CMP) SENSOR

For CMP sensor testing procedure, see CAMSHAFT POSITION (CMP) SENSOR under SENSORS under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article.

CRANKSHAFT POSITION (CKP) SENSOR

For CKP sensor testing procedure, see CRANKSHAFT POSITION (CKP) SENSOR under SENSORS under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article.

DISTRIBUTORLESS IGNITION SYSTEM (DIS) - 4-CYLINDER

Ignition Coil With Built-In Power Transistor (Eclipse 2.4L, Eclipse Spyder 2.4L, Galant 2.4L, Lancer 2.0L & Mirage 1.8L)

1. Disconnect electrical connector and plug wire from ignition coil. Remove ignition coil. Check resistance between coil secondary terminals. Compare resistance to normal value. See «IGNITION COIL WITH BUILT-IN POWER TRANSISTOR SECONDARY RESISTANCE»(ref-135483-S21506504682002022200000). IGNITION COIL WITH BUILT-IN POWER TRANSISTOR SECONDARY RESISTANCE Application (1) Ohms 1.8L 14,000-21,000 2.0L 8500-11,500 2.4L 8500-11,500 (1) At 68°F (20°C).
2. Using a 1.5-volt dry cell battery, connect negative end of battery to coil terminal No. 2 and positive end to coil terminal No. 3. (Scheme 12)
3. Using an analog ohmmeter, check for continuity between coil terminals No. 1 and 2 (connect ohmmeter negative probe to terminal No. 1). Continuity should exist. With positive end of 1.5-volt battery disconnected, continuity should not exist. Replace coil if it fails test.

Scheme 12

Ignition Failure Sensor (Galant 2.4L & Mirage 1.8L)

Using analog ohmmeter, check resistance between ignition failure sensor terminals No. 3 and 4. (Scheme 13) Resistance should be 100 milliohms or less.

Scheme 13

Ignition Coil

Measure primary coil resistance between each individual coil connector terminals. To check secondary coil resistance, measure resistance between towers of each individual coil. Replace coil if primary and secondary coil resistances are not within specification. See V6 DIS IGNITION COIL RESISTANCE .

V6 DIS IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

Power Transistor

1. Disconnect power transistor 6-pin and 3-pin connectors. To test section of power transistor that controls cylinders No. 1 and 4 of ignition coil, connect negative end of 1.5-volt battery to terminal No. 4 of power transistor and positive end to terminal No. 3. (Scheme 14)
2. Using an analog ohmmeter, check for continuity between power transistor terminals No. 4 and 13 (connect negative ohmmeter probe to terminal No. 13). Continuity should exist. With positive end of 1.5-volt battery disconnected, there should be no continuity. Replace power transistor if it fails test.
3. To test section of power transistor that controls cylinders No. 2 and 5 of ignition coil, connect negative end of 1.5-volt battery to terminal No. 4 of power transistor and positive end to terminal No. 2.
4. Using an analog ohmmeter, check for continuity between power transistor terminals No. 4 and 12 (connect negative ohmmeter probe to terminal No. 12). Continuity should exist. With positive end of 1.5-volt battery disconnected, there should be no continuity. Replace power transistor if it fails test.
5. To test section of power transistor that controls cylinders No. 3 and 6 of ignition coil, connect negative end of 1.5-volt battery to terminal No. 4 of power transistor and positive end to terminal No. 1.
6. Using an analog ohmmeter, check for continuity between terminals No. 4 and 11 of power transistor (connect negative ohmmeter probe to terminal No. 11). Continuity should exist. With positive end of 1.5-volt battery disconnected, there should be no continuity. Replace power transistor if it fails test.

Scheme 14

Ignition coil is located in distributor. On Diamante, check primary coil resistance between distributor connector terminals No. 1 and 4. On Eclipse, Eclipse Spyder and Galant 3.0L and Mirage 1.5L, check primary coil resistance between distributor connector terminals No. 1 and 2. (Scheme 15) On Diamante, check secondary coil resistance between distributor tower and distributor assembly connector terminal No. 1 or 4. On Eclipse, Eclipse Spyder, Galant 3.0L and Mirage 1.5L, check secondary coil resistance between distributor assembly connector terminal No. 1 and ignition coil tower. Primary and secondary coil resistance should be within specification. See IGNITION COIL RESISTANCE.

IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)

Scheme 15

Scheme 16

1. Power transistor is located in distributor. Disconnect distributor connector. Using a 1.5-volt dry cell battery, connect negative end of 1.5-volt battery to distributor assembly connector terminal No. 4 and positive end to distributor assembly connector terminal No. 3. (Scheme 15)
2. On Diamante, check for continuity between distributor assembly connector terminals No. 1 and 4. On Eclipse 3.0L, Eclipse Spyder 3.0L, Galant 3.0L and Mirage 1.5L, check for continuity between distributor assembly terminals No. 2 and 4. Continuity should exist. With positive end of 1.5-volt battery disconnected, there should be no continuity. Replace power transistor if it fails test.

IDLE SPEED & IGNITION TIMING

Ignition timing and idle speed are controlled by the Engine Control Module (ECM) or Powertrain Control Module (PCM). Idle speed has been adjusted with the fixed Speed Adjusting Screw (SAS) by the manufacturer. SAS should not need readjusting unless it has been tampered with. For adjustment procedure, see BASIC IDLE SPEED and FIXED SPEED ADJUSTING SCREW (SAS) under IDLE SPEED & MIXTURE in ON-VEHICLE ADJUSTMENTS article.

IGNITION TIMING

1. Connect MUT-II Scan Tool (MB991502) to OBD-II Data Link Connector (OBD-II DLC) located below instrument panel. Start and idle engine. Ensure engine is warmed up, lights, accessories and cooling fan are off, and transmission is in Park or Neutral.
2. Using scan tool or tachometer, check that curb idle speed is within specifications. See «IGNITION TIMING SPECIFICATIONS»(ref-135483-S39201429132002022200000) .
3. Using scan tool, select actuator test No. 17 (base ignition timing). Compare timing with standard base value.
4. Cancel actuator test mode. Check actual timing and compare with standard values. If timing is not within specifications, check Crankshaft Position (CKP) sensor, timing belt cover and CKP sensor installation conditions, and CKP sensing blade condition.

IGNITION TIMING SPECIFICATIONS (Degrees BTDC @ RPM)

CURB IDLE SPEED

1. Connect MUT-II Scan Tool (MB991502) to OBD-II Data Link Connector (OBD-II DLC) located below instrument panel. Start and idle engine. Ensure engine is warmed up, lights, accessories and cooling fan are off, and transmission is in Park or Neutral.
2. Using scan tool or tachometer, check that base ignition timing is within specifications. See «IGNITION TIMING SPECIFICATIONS»(ref-135483-S39201429132002022200000) .
3. Run at idle for 2 minutes. Check curb idle speed. See «CURB IDLE SPEED SPECIFICATIONS»(ref-135483-S36093419472002022200000) .

CURB IDLE SPEED SPECIFICATIONS

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to appropriate SELF-DIAGNOSTICS article. If no Diagnostic Trouble Codes (DTCs) are found in self-diagnostics, proceed to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.