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 .
| Application | Standard psi (kg/cm 2 ) | Minimum psi (kg/cm 2 ) | Minimum RPM |
|---|---|---|---|
| 2.7L (1) | 171 (12.0) | 142 (10.0) | 250 |
| (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 oxygen sensor (O2S) or 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. |
All Models
Remove negative battery terminal. Loosen fuel tank filler cap. Locate 6-mm service bolt on fuel filter. Place clean shop rag around service bolt. To relieve system pressure, slowly loosen service bolt one complete turn. Always replace washer under 6-mm service bolt after loosening.
FUEL PRESSURE
Note. If vehicle starts and runs, fuel pump main relay is okay.
Spark
Check for spark at secondary coil wire and each spark plug wire using a spark tester. If spark is not present, continue with following tests. Check spark plug wire resistance on suspect wires. Resistance should be less than 25,000 ohms.
Ignition Coil Power Source
- On Civic, remove distributor cap to check power source directly at coil. On all models, disconnect ignition coil primary leads. Turn ignition on. Using voltmeter, check voltage between ground and Black/Yellow wire terminal of ignition coil harness.
- Battery voltage should be present. If battery voltage is not present, check for open in Black/Yellow wire between coil and ignition switch.
Ignitor Power Source
Turn ignition off. Disconnect harness connector at distributor. Turn ignition on. Using voltmeter, check for battery voltage between ground and Yellow wire of harness. If voltage is not present, check for open in Black/Yellow or Yellow wire between ignition coil and harness connector. If wire is okay, check ignition coil resistance (for internal short to ground).
Ignitor Check
Check TDC/Crank/CYL sensor resistance values. See TACH PULSE SIGNAL . Check power sources. If no problems are found and spark is not present, replace ignitor.
Scheme 133
- Remove primary and secondary leads from ignition coil. Using an ohmmeter, check resistance between primary terminals "A" and "B" of ignition coil. (Scheme 133) Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-15919-S36964057302000122900000).
- Check resistance between terminals "B" and "D" of ignition coil (tachometer circuit). Resistance should be as specified. See «IGNITION COIL RESISTANCE»(ref-15919-S36964057302000122900000).
- Check secondary resistance between terminal "A" and secondary output terminal (coil tower). See «IGNITION COIL RESISTANCE»(ref-15919-S36964057302000122900000). Check for continuity between terminals "A" and "B". Continuity should exist. If readings are not within specification, replace coil. IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C) Application Primary Secondary C27A4 Engine.3 -.4 14,000-22,000
Scheme 134
- Timing control and triggering of fuel injectors are based upon input signals from TDC/CRANK/CYL sensors. These sensors are simple Permanent Magnet (PM) generator pick-up coils.
- Using a DVOM on low voltage scale (preferably with a bar-graph function), check for a pulsed low-voltage signal at proper Engine Control Module (ECM) harness terminals with engine cranking. Refer to the «WIRING HARNESS & SENSOR RESISTANCE TEST»(ref-15919-S23843326992000122900000). Also (Scheme 134) If a pulsed signal is present, fault does not exist. If pulsed signal is not present, check sensor and wiring integrity.
- To test sensor and wiring integrity, turn ignition off. Disconnect connectors from ECM. Lightly probe appropriate ECM harness terminals to check for proper winding resistance of each sensor. See «WIRING HARNESS & SENSOR RESISTANCE TEST»(ref-15919-S23843326992000122900000). If resistance is within specification, go to step 5). If resistance is not within specification, go to next step.
- Check resistance of TDC/CRANK/CYL sensor directly at sensor connector. See «TDC/CRANK/CYL SENSOR RESISTANCE TEST»(ref-15919-S18595901402000122900000). If sensor resistance is within specification, repair open, short or corrosion in wire harness between sensor(s) and ECM. If resistance is not within specification, replace sensor.
- Check continuity to ground at each ECM sensor terminal. If continuity is not present, replace distributor housing. If continuity is present, go to next step.
- Disconnect sensor(s) and recheck for continuity to ground at ECM harness sensor terminals. If continuity no longer exists, go to next step. If continuity to ground is still present, repair short to ground in ECM harness between ECM and sensor(s).
- Check continuity to ground on each sensor connector terminal. See «TDC/CRANK/CYL SENSOR RESISTANCE TEST»(ref-15919-S23843326992000122900000). Continuity should not exist. If continuity to ground exists, replace sensor. WIRING HARNESS & SENSOR RESISTANCE TEST Application Terminals Ohms CRANK B8 & B16 1800-2500 CYL B6 & B14 1500-3000 TDC B7 & B15 1500-3000 TDC/CRANK/CYL SENSOR RESISTANCE TEST (1) Application Terminals Wire Color CRANK Sensor Wire 1 Of 2 1 Blue 2 Of 2 2 White CYL Sensor Wire Term. No. 3 B6 Yellow Term. No. 4 B14 Black TDC Sensor Wire Term. No. 1 B7 Green Term. No. 2 B15 Red (1) CRANK sensor is located behind crankshaft pulley and CYL/TDC sensor is located behind front camshaft pulley.
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 - 2.7L article.
| Application | RPM |
|---|---|
| 2.7L | 500-600 |
| (1) With Electronic Air Control Valve (EACV) or Idle Air Control (IAC) valve disconnected, headlights and cooling fan off, and transmission in Neutral or Park. | |
| (1) | With Electronic Air Control Valve (EACV) or Idle Air Control (IAC) valve disconnected, headlights and cooling fan off, and transmission in Neutral or Park. |
IDLE SPEED SPECIFICATIONS (1)
| Application | Specification |
|---|---|
| 2.7L | 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 - OBD-II (2.7L) article. If no hard codes are found in self-diagnostics, refer to the appropriate TESTS W/O CODES - 2.7L article for diagnosis by symptom (i.e., ROUGH IDLE, NO-START, etc.), or intermittent diagnostic procedures.
