Compression
Check engine mechanical condition using a compression gauge, vacuum gauge or engine analyzer. See engine analyzer manual for specific instructions. Check engine compression with engine at normal operating temperature at specified cranking speed, all spark plugs removed and throttle wide open.
| WARNING | DO NOT use ignition switch during compression tests on fuel injected vehicles. 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 or contaminate engine oiling system. |
| Application | Specification | ||
|---|---|---|---|
| Compression Ratio | |||
| Accent (1.5L) | 10:1 | ||
| Elantra (1.8L) | 10.0:1 | ||
| Sonata | |||
| 2.0L | 9.0:1 | ||
| 3.0L | 8.9:1 | ||
| Tiburon (2.0L) | 10.3:1 | ||
| Compression Pressure | |||
| Accent (1.5L) | 234 psi (16 kg/cm 2 ) | ||
| Elantra (1.8L) | 213 psi (15 kg/cm 2 ) | ||
| Sonata | |||
| 2.0L | 170 psi (12 kg/cm 2 ) | ||
| 3.0L | 170 psi (12 kg/cm 2 ) | ||
| Tiburon (2.0L) | 213 psi (15 kg/cm 2 ) | ||
| Maximum Variation Between Cylinders (All Models) | 14 psi (.9 kg/cm 2 ) | ||
COMPRESSION SPECIFICATIONS
Exhaust System Backpressure
Exhaust system can be checked with a vacuum or pressure gauge. If using a pressure gauge, remove HO2S sensor. Connect a 1-5 psi (.07-.35 kg/cm 2 ) pressure gauge and run engine at 2500 RPM. If exhaust system backpressure is greater than 2 psi (.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 gauge reading 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 PRESSURE RELEASE
Disconnect fuel pump harness connector located under rear seat. Start engine. After engine stalls, turn ignition off. Disconnect negative battery cable. Reconnect fuel pump harness connector.
Accent, Elantra & Tiburon
- Remove SFI control relay located under left side of instrument panel, near fuse panel. Apply battery voltage across relay terminals No. 2 (negative) and No. 4 (positive). (Scheme 10) Using ohmmeter, check continuity between terminals No. 1 and No. 5. Continuity should exist until voltage is disconnected.
- Reapply battery voltage between terminals No. 2 and 4. Check continuity between terminals No. 3 and 5. Continuity should exist until voltage is disconnected. Replace relay if it fails any test.
Sonata
- Remove control relay. Relay is located behind right kick panel, near ECM. Apply battery voltage across terminals No. 6 (positive) and No. 8 (negative) while checking voltage on terminal No. 1. (Scheme 11) Battery voltage should exist.
- Apply battery voltage across terminals No. 7 (positive) and No. 10 (negative) while checking continuity between terminals No. 3 and 4. Continuity should exist until voltage is disconnected. Apply battery voltage across terminals No. 3 (positive) and No. 9 (negative) while checking voltage at terminal No. 4. Battery voltage should exist. Replace relay if it fails any test.
Scheme 10
Scheme 11
DIRECT IGNITION SYSTEM (DIS - 1.5L, 1.8L & 2.0L)
Note. Accent, Elantra and Tiburon are not equipped with a power transistor.
Spark (Spark Plug)
Connect spark plug to a high tension cable. Ground outer electrode (main body of spark plug), and crank engine. Spark should occur in discharge gap between electrodes. Ensure spark plug gap is .039-.043" (1.0-1.1 mm).
Ignition Coil Power Source
Disconnect ignition coil connector. Turn ignition on. Using voltmeter, check voltage between terminal No. 3 and ground. (Scheme 12)or (Scheme 13). Battery voltage should exist.
Ignition Coil Resistance
- Using an ohmmeter, check primary coil resistance for cylinders No. 1 and 2 between coil connector terminals No. 1 and No. 3. Check resistance for cylinders No. 3 and No. 4 between connector terminals No. 2 and No. 3. (Scheme 12)or (Scheme 13). See DIS IGNITION COIL RESISTANCE table.
- To check secondary coil resistance, disconnect ignition coil connector. Check resistance between coil towers No. 1 and No. 4 and between coil towers No. 2 and No. 3. See DIS IGNITION COIL RESISTANCE table. Replace coil if readings are not within specification.
| Application | Primary | Secondary |
|---|---|---|
| Accent (1.5L) | .45-.55 | 10,300-13,900 |
| Elantra (1.8L) | .45-.55 | 10,300-13,900 |
| Sonata (2.0)L | .77-.95 | 10,300-13,900 |
| Tiburon | .45-.55 | 10,300-13,900 |
DIS IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)
Scheme 12
Scheme 13
Power Transistor (Sonata 2.0L)
Connect negative terminal of a 3-volt power source (equivalent to 2 flashlight batteries connected in series) to terminal No. 2 of power transistor. Check for continuity between terminals No. 2 and 3 with positive terminal of power source connected to terminal No. 1. (Scheme 14) If continuity exists only when 3 volts is applied, power transistor is okay. If continuity does not exist, replace power transistor
Scheme 14
Spark (Coil)
- Check for spark at coil wire. Hold wire about 1/4" from an engine ground, and crank engine. If spark is produced, coil is okay. If spark is not produced, use a voltmeter to check voltage at negative side of coil (tach signal) while cranking engine.
- If voltage does not exist, see IGNITION COIL POWER SOURCE. If voltage does not fluctuate, check coil wiring, power transistor, ECU and distributor assembly. If voltage fluctuates, check coil resistance, coil wire and connections.
Connect spark plug to a high tension cable. Ground outer electrode (main body of spark plug) and crank engine. Spark should occur in discharge gap between electrodes. Ensure spark plug gap is .039-.043" (1.0-1.1 mm).
Disconnect coil primary connector. Turn ignition on. Using voltmeter, check voltage between positive terminal and ground. Battery voltage should exist.
- Remove primary and secondary leads from ignition coil. Using an ohmmeter, check primary resistance between positive and negative terminals of coil. See EIS IGNITION COIL RESISTANCE table.
- Check secondary resistance between ignition coil positive terminal (Black/White wire) and ignition coil tower. See EIS IGNITION COIL RESISTANCE table. Replace coil if readings are not within specification.
| Application | Primary | Secondary |
|---|---|---|
| Sonata 3.0L | .72-.88 | 10,300-13,900 |
EIS IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)
Power Transistor
Connect negative terminal of a 3-volt power source (equivalent to 2 flashlight batteries connected in series) to terminal No. 2 of power transistor. Check for continuity between terminals No. 2 and 3 with positive terminal of power source connected to terminal No. 1. (Scheme 14) If continuity exists only when 3 volts is applied, power transistor is okay. If continuity does not exist, replace power transistor
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specification. For adjustment procedures, see ADJUSTMENTS article.
SUMMARY
If no faults were found while performing BASIC TESTING proceed to appropriate TESTS W/CODES article; For Accent see TESTS W/CODES article, for Elantra and Tiburon see TESTS W/CODES article, for Sonata 2.0L see TESTS W/CODES article, for Sonata 3.0L see 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.