Compression
Check engine mechanical condition using a compression gauge, vacuum gauge or an engine analyzer. See engine analyzer manual for specific instructions.
| 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 the engine's oiling system. |
| Application | (1) Specification |
|---|
| Compression Ratio | 9.5:1 |
| Compression Pressure |
| Standard | 199 psi (14.0 kg/cm 2 ) |
| Limit | (2) 170 psi (11.9 kg/cm 2 ) |
| (1) Checked at 400 RPM. (2) Maximum variation between cylinders is 14.2 psi (.9 kg/cm 2 ). |
| (2) | Maximum variation between cylinders is 14.2 psi (.9 kg/cm 2 ). |
COMPRESSION SPECIFICATIONS
Exhaust System Backpressure
- Exhaust system backpressure can be checked with a vacuum or pressure gauge. If using a pressure gauge, remove oxygen sensor. 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 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
Note. See CIRCUIT TESTS for diagnosis of a no-start or rough running condition related to a fuel system problem.
| 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
| CAUTION | DO NOT perform this procedure when engine is hot. Doing so may have an adverse effect on catalytic convertor. |
- Place transmission in Neutral (M/T) or Park (A/T). Set parking brake and block drive wheels. Disconnect fuel pump relay. See «FUEL PUMP RELAY LOCATION»(ref-26216-S36440411102001010500000) table.
- Remove fuel filler cap to release fuel vapor pressure in fuel tank. Reinstall fuel filler cap. Start engine and run until engine dies. After engine dies, crank engine 2-3 times for about 3 seconds to dissipate fuel pressure in lines. To restore normal operation, reinstall fuel pump relay.
| Application | Location |
|---|
| X-90 | Passenger Compartment, Attached To Heater Case |
Fuel System Circuit
Turn ignition on, leaving engine off. Fuel pump should operate for 2 seconds. If fuel pump does not operate, check fuses, fuel pump relay, fuel pump, all electrical connections and PCM. See CIRCUIT TESTS .
IGNITION CHECKS
Note. To diagnose a no-spark condition, perform all procedures listed under IGNITION CHECKS .
IGNITOR (POWER UNIT)
- Disconnect distributor harness connector. Connect two 1.5 volt batteries together in series (3 volts). Using an ohmmeter, connect positive lead to terminal No. 4 of distributor and negative lead to terminal No. 6. (Scheme 5)
- Check continuity between terminals No. 4 and 6 as positive side of batteries is connected to terminal No. 5 of distributor and negative side is connected to terminal No 4. (Scheme 5) Continuity should only exist with voltage applied to terminal No. 5. Replace distributor if continuity is not as specified.
Scheme 5
IGNITION COIL RESISTANCE
Remove secondary coil wire and primary wire connector from coil. Using an ohmmeter, check coil primary and secondary resistances. (Scheme 6) Replace coil if resistance is not within specification. See IGNITION COIL RESISTANCE table.
| Application | Primary | Secondary |
|---|
| X-90 | 0.7-0.9 | 13,000-18,000 |
IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)
Scheme 6
CAMSHAFT POSITION (CMP) SENSOR
Note. Camshaft Position (CMP) sensor may also be known as a pick-up coil or Hall Effect sensor.
Note. Vehicles do not provide separate circuit testing for CMP sensor. See TESTS W/CODES article.
| Application | (2) Ohms Cold | (3) Ohms Hot |
|---|
| X-90 | (4) | (4) |
| (1) Also referred to as pick-up coil or Hall Effect sensor. (2) Cold is 14-122°F (-10-50°C). (3) Hot is 122-212°F (50-100°C). (4) Information not available. |
| (1) | Also referred to as pick-up coil or Hall Effect sensor. |
| (2) | Cold is 14-122°F (-10-50°C). |
| (3) | Hot is 122-212°F (50-100°C). |
| (4) | Information not available. |
CMP SENSOR RESISTANCE (1)
| Application | In. (mm) |
|---|
| X-90 | (2) |
| (1) Also referred to as pick-up coil or Hall Effect sensor. (2) Not adjustable. |
| (1) | Also referred to as pick-up coil or Hall Effect sensor. |
IDLE SPEED & IGNITION TIMING
Ensure idle speed and base ignition timing are set to specification. See IDLE SPEED SPECIFICATIONS and IGNITION TIMING tables. If necessary, see ADJUSTMENTS article for adjustment procedures.
| Application | Idle RPM |
|---|
| A/C Off | 750-850 |
| A/C On | 950-1050 |
| (1) Transaxle or transmission in Neutral or Park. |
| (1) | Transaxle or transmission in Neutral or Park. |
IDLE SPEED SPECIFICATIONS (1)
| Application | (2) Percent |
|---|
| X-90 | 50 |
| (1) See IDLE SPEED SPECIFICATIONS table. (2) With A/C turned off (if equipped). |
| (1) | See IDLE SPEED SPECIFICATIONS table. |
| (2) | With A/C turned off (if equipped). |
IAC DUTY AT SPECIFIED IDLE SPEED (1)
| Application | Man. Trans. | Auto. Trans. |
|---|
| X-90 | (2) 4-6 @ 800 | (2) 4-6 @ 800 |
| (1) See ADJUSTMENTS article for adjustment procedures. (2) With jumper wire installed between terminals "D" and "E" of test connector located near coolant recovery bottle. |
| (1) | See ADJUSTMENTS article for adjustment procedures. |
| (2) | With jumper wire installed between terminals "D" and "E" of test connector located near coolant recovery bottle. |
IGNITION TIMING (Degrees BTDC @ RPM) (1)
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.
CIRCUIT TESTS
| Application | Circuit Test |
|---|
| Fuel Injector Circuit | B-1 |
| Fuel Pump Circuit | B-2 |
| Fuel Pressure Inspection | B-3 |
Note. See PIN VOLTAGE CHARTS article and appropriate wiring diagrams in WIRING DIAGRAMS article for PCM connector and wire terminal identification.
