Compression
Check engine mechanical condition with a compression gauge, vacuum gauge, or an engine analyzer. See engine analyzer manufacturer's manual for specific instructions.
| WARNING | DO NOT use ignition switch during compression test. Use a remote starter to crank engine. Fuel injectors on many models are triggered by ignition switch during cranking mode, which can create a fire hazard, contaminate the engine's oiling system or cause damage to catalytic converter. |
Check compression pressure with engine at normal operating temperature, all spark plugs removed, throttle valves wide open and at specified cranking speed. Crank engine at least 6 revolutions to determine engine compression. See ENGINE COMPRESSION .
| Model | Standard psi (kg/cm 2 ) | Minimum psi (kg/cm 2 ) | Minimum RPM |
|---|---|---|---|
| Odyssey (1) | 178 (12.5) | 135 (9.5) | 200 |
| (1) Maximum variation between cylinders is 28 psi (2.0 kg/cm 2 ). | |||
| (1) | Maximum variation between cylinders is 28 psi (2.0 kg/cm 2 ). |
ENGINE COMPRESSION
Exhaust System Backpressure
Exhaust system can be checked using a vacuum or pressure gauge. Remove front (primary) heated oxygen sensor (HO2S). Connect a 0-5 psi pressure gauge, and run engine at 2500 RPM. If exhaust system backpressure exceeds 1 3/4 - 2 psi (.12-.14 kg/cm 2 ), 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 slowly drops after stabilizing, check exhaust system for restrictions.
FUEL SYSTEM
| WARNING | Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. |
FUEL SYSTEM PRESSURE RELEASE
Remove negative battery terminal. Remove fuel tank filler cap. Locate 6-mm service bolt on fuel rail. Place clean shop rag around service bolt. To relieve system pressure, slowly loosen service bolt one complete turn while holding banjo bolt with another wrench. Always replace washer under 6-mm service bolt after loosening.
FUEL PRESSURE
Note. If vehicle starts and runs, fuel pump main relay is okay.
IGNITION CHECKS
Note. For ignition system check information on Passport, refer to Rodeo in Isuzu BASIC TESTING article.
Spark
Check for spark at secondary coil wire and each spark plug wire using a spark tester. Check spark plug wire resistance on suspect wires. Resistance should be less than 25,000 ohms.
Scheme 1
- Turn ignition off. Remove primary and secondary leads from ignition coil. Using an ohmmeter, check primary resistance between ignition coil connector terminals "A" and "B". (Scheme 1) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-16061-S38222488992000122900000).
- Check secondary resistance between ignition coil connector terminal "A" and secondary output terminal (coil tower). See «IGNITION COIL RESISTANCE»(ref-16061-S38222488992000122900000). Check for continuity between terminals "A" and "C". Continuity should exist. If readings are not within specification, replace coil.
Scheme 2
- Turn ignition off. Remove distributor cap. Remove primary leads from ignition coil. Using an ohmmeter, check primary resistance between ignition coil terminals "A" (+) and "B" (-). (Scheme 2) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-16061-S38222488992000122900000).
- Check secondary resistance between ignition coil terminal "A" (+) and secondary output terminal (coil tower). See «IGNITION COIL RESISTANCE»(ref-16061-S38222488992000122900000). If readings are not as specified, replace ignition coil. IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C) Application Primary Secondary Odyssey.4-.6 22,000-34,000
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specification. See IDLE SPEED SPECIFICATIONS and IGNITION TIMING . For adjustment procedures, see ADJUSTMENTS article.
| Application | RPM |
|---|---|
| Odyssey | (1) 500-600 |
| (2) 650-750 | |
| (3) 720-820 | |
| (1) With Idle Air Control (IAC) valve disconnected, headlights and cooling fan off, and transmission in Neutral or Park. (2) With Idle Air Control (IAC) valve connected, headlights and cooling fan off, and transmission in Neutral or Park. (3) With headlights on low or heater fan on HI and A/C on. | |
| (1) | With Idle Air Control (IAC) valve disconnected, headlights and cooling fan off, and transmission in Neutral or Park. |
| (2) | With Idle Air Control (IAC) valve connected, headlights and cooling fan off, and transmission in Neutral or Park. |
| (3) | With headlights on low or heater fan on HI and A/C on. |
IDLE SPEED SPECIFICATIONS
| Application | Specification |
|---|---|
| Odyssey | 13-17 @ 650-750 |
IGNITION TIMING (Degrees BTDC @ RPM)
SUMMARY
If no faults were found while performing BASIC DIAGNOSTIC PROCEDURES, proceed to TESTS W/CODES article. If no hard codes are found in self-diagnostics, proceed to TESTS W/O CODES article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.), or intermittent diagnostic procedures.
