Engine Controls - Basic Testing - 2.4L 4-CYL: Other Mitsubishi Eclipse II

Compression

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

COMPRESSION SPECIFICATIONS

Exhaust System Backpressure

Exhaust system can be checked with a vacuum or pressure gauge. Remove oxygen sensor or air injection check valve (if equipped). Connect a 0-5 psi pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 1 3/4 - 2 psi, exhaust system or catalytic converter is plugged.

If using a vacuum gauge, connect vacuum gauge hose to intake manifold vacuum port and start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, exhaust system should be checked for a restriction.

FUEL SYSTEM

Relieving Fuel Pressure

1. Remove rear seat cushion and remove access plate if required to disconnect fuel pump harness connector.
2. Start engine. Let engine run until it stops. Turn ignition off. Disconnect negative battery cable. Connect fuel pump harness connector. Reinstall rear seat (if necessary.) WARNING: Before disconnecting high pressure fuel hose at fuel delivery pipe, cover fuel hose connection with a rag. Some residual fuel pressure may still be in system.

Scheme 73

1. Disconnect high pressure fuel hose at fuel delivery pipe. Remove throttle body bracket (if necessary). Connect fuel pressure gauge with adapter between fuel delivery pipe and high pressure hose. (Scheme 73)
2. Connect negative battery cable. Operate fuel pump by connecting battery voltage to fuel pump test terminal. See «FUEL PUMP TEST TERMINAL LOCATION»(ref-19192-S25608967012000123000000) table. Ensure no fuel leaks are present. Disconnect battery voltage from fuel pump test terminal. FUEL PUMP TEST TERMINAL LOCATION Application Wire Color Location Eclipse Black/Blue (1) Galant Black/Blue (2) Pickup Black/Blue (3) Summit Wagon Black/Blue (2) (1) On main wiring harness, near wiper motor on firewall, behind battery. (2) On main wiring harness, near left center of firewall. (3) Near left rear corner of engine compartment, below cruise control actuator (if equipped).
3. 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-19192-S41245728422000123000000) table. Disconnect and plug vacuum hose from fuel pressure regulator. Record fuel pressure reading.
4. Check for fuel pressure in fuel return hose by gently pinching hose while increasing engine speed. If fuel volume is low, fuel pressure in return hose will not be felt. Increase engine speed to 2500-3000 RPM, 2-3 times. Return engine to idle. Fuel pressure should not drop when engine is returned to idle.
5. Turn ignition off. Ensure fuel pressure reading does not decrease within 2 minutes. If a decrease is noted, monitor speed of decrease.
6. If fuel pressure is lower than specification, fuel pressure drops at idle after increasing engine speed to 2500-3000 RPM, or no fuel pressure in fuel return hose can be felt, check for clogged fuel filter, or faulty fuel pressure regulator or fuel pump.
7. 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.
8. If fuel pressure decreases suddenly after engine is stopped, check valve in fuel pump is not seated. Replace fuel pump. If fuel pressure drops slowly, fuel injector is leaking or fuel pressure regulator valve seat is leaking. Check for faulty fuel injector or fuel pressure regulator. Repair as necessary.
9. 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 hose. Check for fuel leaks.

FUEL PUMP PERFORMANCE

MFI Control Relay

Multipurpose relay switches power to vehicle sensors and actuators including Volume Airflow (VAF) sensor, crankshaft position sensor, idle speed control, injectors and fuel pump. When ignition switch is turned to ON position, PCM energizes coils controlling injectors, VAF sensor and idle air control. When ignition switch is turned to START position, PCM energizes coils (through park/neutral position switch on A/T models) to supply power to fuel pump. Relay failure will cause a no-start condition. For testing procedure, see SYSTEM/COMPONENT TESTS - 2.4L 4-CYL article.

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.

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 22 k/ohms.

CAMSHAFT POSITION (CMP) SENSOR

For CMP sensor testing procedure, see TESTS W/CODES - 2.4L 4-CYL article.

CRANKSHAFT POSITION (CKP) SENSOR

For CKP sensor testing procedure, see TESTS W/CODES - 2.4L 4-CYL article.

Scheme 74

1. Disconnect ignition coil connector. Using a Digital Volt-Ohmmeter (DVOM), measure primary coil resistance between ignition coil connector terminals No. 2 and 3 (coil for cylinders No. 1 and 4) and terminals No. 1 and 3 (coil for cylinders No. 2 and 3). (Scheme 74)
2. Remove ignition wires from coil. Measure secondary coil resistance between coil towers for cylinders No. 1 and 4 and between coil towers for cylinders No. 2 and 3. Primary and secondary coil resistance should be within specification. See «ECLIPSE IGNITION COIL RESISTANCE»(ref-19192-S39087663342000123000000) table. Connect coil harness connector. Connect ignition wires to coil.

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

Scheme 75

1. To test the section of the power transistor that controls cylinders No. 1 and 4, disconnect power transistor connector. Using a 1.5-volt dry cell battery, connect negative end of battery to terminal No. 3 of power transistor and positive end to terminal No. 7. (Scheme 75)
2. Using an analog ohmmeter, check for continuity between terminals No. 3 and 8 of power transistor. 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 the section of the power transistor that controls cylinders No. 2 and 3, connect negative end of 1.5-volt dry cell battery to terminal No. 3 of power transistor and positive end to terminal No. 2.
4. Using an analog ohmmeter, check for continuity between terminals No. 1 and 3 of power transistor. Continuity should exist. With positive end of 1.5-volt battery disconnected, there should be no continuity. Replace power transistor if it fails test.

Ignition Coil Resistance

Using a DVOM, measure primary coil resistance between positive and negative terminals of coil. (Scheme 77) Measure secondary coil resistance between coil positive terminal and ignition coil tower. Primary and secondary coil resistance should be within specification. See IGNITION COIL RESISTANCE table.

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

Scheme 76

Scheme 77

Power Transistor (Pickup)

1. Disconnect power transistor connector. Using a 1.5-volt dry cell battery, connect negative end of 1.5-volt battery to terminal No. 2 of power transistor and positive end to terminal No. 1. (Scheme 78)
2. Using an analog ohmmeter, check for continuity between terminals No. 2 and 3 of power transistor. 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 78

Scheme 79

1. Disconnect power transistor connector. Using a 1.5-volt dry cell battery, connect negative end of 1.5-volt battery to terminal No. 5 of power transistor and positive end to terminal No. 6. (Scheme 78)
2. Using an analog ohmmeter, check for continuity between terminals No. 5 and 12 of power transistor. 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

Ensure idle speed and ignition timing are set to specification. See IGNITION TIMING SPECIFICATIONS table. For adjustment procedures, see ADJUSTMENTS - 2.4L 4-CYL article.

IGNITION TIMING SPECIFICATIONS (Degrees BTDC @ RPM)

SUMMARY

If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to TESTS W/CODES - 2.4L 4-CYL article. If no hard codes are found in self-diagnostics, proceed to TESTS W/O CODES - 2.4L 4-CYL article for diagnosis by symptom (i.e., ROUGH IDLE, NO START, etc.) or intermittent diagnostic procedures.