Compression
Check engine mechanical condition using a compression gauge, vacuum gauge or an engine analyzer. See engine analyzer manual for specific instructions.
| Application | Specification | ||
|---|---|---|---|
| Normal Compression Pressure | |||
| Altima | 178 psi (12.5 kg/cm 2 ) | ||
| NX & Sentra | |||
| 1.6L | 192 psi (13.5 kg/cm 2 ) | ||
| 2.0L | 178 psi (12.5 kg/cm 2 ) | ||
| Pickup | 192 psi (13.5 kg/cm 2 ) | ||
| 240SX | 179 psi (12.6 kg/cm 2 ) | ||
| Minimum Compression Pressure | |||
| Altima | 149 psi (10.5 kg/cm 2 ) | ||
| NX & Sentra | |||
| 1.6L | 164 psi (11.5 kg/cm 2 ) | ||
| 2.0L | 149 psi (10.5 kg/cm 2 ) | ||
| Pickup | 142 psi (10.0 kg/cm 2 ) | ||
| 240SX | 151 psi (10.6 kg/cm 2 ) | ||
| Maximum Variation Between Cylinders | |||
| All Models | 14 psi (1.0 kg/cm 2 ) | ||
4-CYLINDER COMPRESSION SPECIFICATIONS
| Application | Specification | ||
|---|---|---|---|
| Normal Compression Pressure | |||
| Maxima | |||
| VE30DE | 183 psi (12.9 kg/cm 2 ) | ||
| VG30E | 173 psi (12.2 kg/cm 2 ) | ||
| Pathfinder, Pickup & Quest | 173 psi (12.2 kg/cm 2 ) | ||
| 300ZX | |||
| Non-Turbo | 186 psi (13.1 kg/cm 2 ) | ||
| Turbo | 171 psi (12.0 kg/cm 2 ) | ||
| Minimum Compression Pressure (1) | |||
| Maxima | |||
| VE30DE | 142 psi (10.0 kg/cm 2 ) | ||
| VG30E | 128 psi (9.0 kg/cm 2 ) | ||
| Pathfinder, Pickup & Quest | 128 psi (9.0 kg/cm 2 ) | ||
| 300ZX | |||
| Non-Turbo | 142 psi (10.0 kg/cm 2 ) | ||
| Turbo | 128 psi (9.0 kg/cm 2 ) | ||
| Maximum Variation Between Cylinders | |||
| All Models | 14 psi (1.0 kg/cm 2 ) | ||
| (1) Minimum compression at 300-350 RPM. | |||
| (1) | Minimum compression at 300-350 RPM. |
V6 COMPRESSION SPECIFICATIONS
Exhaust System Backpressure
Exhaust system can be checked using a vacuum or pressure gauge. If using a pressure gauge, remove O2 sensor or air injection check valve (if equipped). Connect a 0-5 psi pressure gauge. Run engine at 2500 RPM. If exhaust system backpressure is greater than 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. Start engine. Observe vacuum gauge. Open throttle part way and hold steady. If vacuum gauge reading slowly drops after stabilizing, check exhaust system for a restriction.
FUEL PRESSURE
Begin basic diagnosis of fuel system by determining fuel system pressure. If fuel pump is inoperative, check fuel pump fuse. If fuse is okay, see FUEL SYSTEM in I - SYS/COMP TESTS article. See L -WIRING DIAGRAMS article for specific circuit or wire color.
| WARNING | Always relieve fuel pressure before disconnecting any fuel injection-related component. DO NOT allow fuel to contact engine or electrical components. If connecting fuel pressure gauge to fuel system without using a "T" connector, DO NOT operate fuel pump for more than a few seconds. Operating fuel pump longer than a few seconds under this condition can damage fuel pump. |
- To relieve fuel system pressure, remove fuel pump fuse (fuel pump relay on 300ZX). Start engine, and allow it to run until it stalls. Crank engine 2 or 3 more times to verify all pressure has dissipated.
- Turn ignition off. Install fuel pump fuse or relay. Connect fuel gauge between fuel filter outlet and fuel tube using a "T" connector. Disconnect electrical connector at fuel pressure regulator control solenoid valve (if equipped).
- Start engine. Check fuel line connections for leaks. Check fuel pressure with engine idling. Disconnect vacuum hose from pressure regulator. Recheck fuel pressure.
- Compare fuel pressure readings on pressure gauge with specifications in FUEL PRESSURE table. Release fuel system pressure as described in step 1). Disconnect fuel pressure gauge. Reconnect fuel lines. Start engine and check for fuel leaks.
| Application | At Idle W/O Vacuum psi (kg/cm 2 ) | At Idle W/ Vacuum psi (kg/cm 2 ) | |
|---|---|---|---|
| Altima, Quest & 240SX | 43 (3.0) | 34 (2.4) | |
| Maxima | 44 (3.1) | 36 (2.5) | |
| NX, Sentra & 300ZX | 43 (3.0) | 36 (2.5) | |
| Pathfinder & Pickup | |||
| 4-Cylinder | 43 (3.0) | 33 (2.3) | |
| V6 | 43 (3.0) | 34 (2.4) | |
FUEL PRESSURE
IGNITION CHECKS
Note. Maxima VE30DE and 300ZX use distributorless ignition system.
DISTRIBUTOR IGNITION
To determine cause of no-spark condition, perform following tests in order given. Deviation from this procedure may cause false diagnosis and replacement of non-defective components.
Spark
Check for spark at coil wire and each spark plug wire using spark tester. DO NOT crank engine continuously for more than 2 seconds. Inspect secondary coil wire for arcing while testing spark at plugs. Check electrical connections at Crankshaft Position (CKP) sensor, ignition coil and power transistor.
Ignition Coil Power Source
- Disconnect ignition coil 2-pin connector. Turn ignition on. Check for voltage at specified wire terminal. See IGNITION COIL POWER SOURCE TERMINAL IDENTIFICATION table.
- If voltage is present, go to POWER TRANSISTOR. If voltage is not present, check continuity of entire circuit between battery and ignition coil, including fuse link and ignition switch.
| Application | Wire Color |
|---|---|
| Altima | Black/Red |
| NX & Sentra | Green/Yellow |
| Maxima | White/Green |
| Pathfinder & Pickup | Black/White |
| Quest | Red |
| 240SX | Light Green/Black |
IGNITION COIL POWER SOURCE TERMINAL IDENTIFICATION
Power Transistor
For power transistor system testing, see appropriate CODE 21 (NO IGNITION REFERENCE) in TESTS W/CODES article. For power transistor component testing, see IGNITION SYSTEMS in appropriate I -SYS/COMP TESTS article.
Ignition Coil Resistance
- If ignition coil malfunction is suspected, carefully inspect external housing for burned spots indicating secondary circuit arcing to primary or ground circuits. Disconnect ignition coil primary 2-pin connector.
- Using an ohmmeter, check resistance between primary connector terminals. Check resistance between secondary tower and positive terminal of coil primary connector. Positive terminal is identified by wire color in IGNITION COIL POWER SOURCE TERMINAL IDENTIFICATION table. If either resistance is not as specified, replace ignition coil. See appropriate IGNITION COIL RESISTANCE table.
| Application | Primary | Secondary | |
|---|---|---|---|
| Altima & 240SX | 1.0 | 10,000 | |
| NX & Sentra | |||
| 1.6L | .9 | 13,000 | |
| 2.0L | 1.0 | 10,000 | |
| Pickup | .7 | (1) | |
| (1) Secondary resistance cannot be read on Pickup. | |||
| (1) | Secondary resistance cannot be read on Pickup. |
4-CYLINDER IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)
| Application | Primary | Secondary |
|---|---|---|
| Maxima (VG30E) | 1.0 | 8200-12,400 |
| Pathfinder, Pickup & Quest | 1.0 | 10,000 |
V6 IGNITION COIL RESISTANCE - Ohms @ 68°F (20°C)
Crankshaft Position (CKP) Sensor
- CKP sensor is located inside distributor. If a fault is present in CKP sensor, Code 11 may be set in ECM memory. If Code 11 is set, perform appropriate CODE 11 (CKP SENSOR) in TESTS W/CODES article.
- To test CKP sensor, remove distributor. Leave wiring harness connected. Using a voltmeter, connect negative lead to ground and alternately connect positive lead to 1-degree signal terminal and 120/180-degree signal terminal. See CKP SENSOR INPUT SIGNAL TERMINALS table. (Scheme 1)- (Scheme 3).
- Measure voltages at both terminals while rotating distributor by hand. Voltage should fluctuate 0-5 volts. If either voltage signal does not fluctuate 0-5 volts, check harness for short or open circuit. If no problems are found, replace CKP sensor.
| Application | 1-Degree Signal | 120/180-Degree Signal | |
|---|---|---|---|
| Altima & 240SX | Terminal No. 2 | Terminal No. 1 | |
| Maxima & Quest | Terminal No. 4 | Terminal No. 3 | |
| NX & Sentra | |||
| 1.6L | Terminal No. 2 | Terminal No. 1 | |
| 2.0L | Terminal "D" | Terminal "A" | |
| Pickup & Pathfinder | |||
| 2.4L | Terminal "D" | Terminal "A" | |
| 3.0L | Terminal No. 4 | Terminal No. 3 | |
CKP SENSOR INPUT SIGNAL TERMINALS
Scheme 1
Scheme 2
Scheme 3
DISTRIBUTORLESS IGNITION (EI) SYSTEM
To determine cause of no-spark condition, perform following tests in order given. Deviation from this procedure may cause false diagnosis and replacement of non-defective components.
Ignition Coil Power Source & Ground
- Disconnect 3-pin ignition coil connector. Turn ignition on. Check voltage between ground and terminal "B" of ignition coil connector. (Scheme 4)
- If battery voltage is not present, go to IGNITION COIL/POWER TRANSISTOR RELAY. If battery voltage exists, turn ignition off. Check continuity between ground and ignition coil connector terminal "A".
- If continuity does not exist, repair ground circuit between ignition coil connector terminal "A" and ground. Repeat test for remaining coils.
Ignition Coil/Power Transistor Relay
Connect 12-volt power source between relay connector terminals No. 1 and 2. (Scheme 5) Check continuity between terminals No. 3 and 5. If continuity does not exist, replace relay. Disconnect power source. Check continuity between relay connector terminals No. 3 and 5. If continuity exists, replace relay.
Scheme 4
Scheme 5
Disconnect ignition coil connector. Check primary resistance between terminals "B" and "C" of ignition coil connector. (Scheme 6) Resistance should be about 0.75 ohm. If resistance is not as specified, replace ignition coil.
Scheme 6
CKP Sensor
- If a fault is present in CKP sensor, Code 11 may be set in ECM memory. If Code 11 is set, perform appropriate CODE 11 (CKP SENSOR) in TESTS W/CODES article.
- To test CKP sensor, remove distributor. Leave wiring harness connected. Using a voltmeter, connect negative lead to ground and alternately connect positive lead to terminal "A" (120-degree signal) and terminal "B" (1-degree signal). (Scheme 7)
- Measure voltages while rotating distributor by hand. Voltage should fluctuate 0-5 volts. If either voltage signal does not fluctuate 0-5 volts, check harness for short or open circuit. If no problems are found, replace CKP sensor.
Power Transistor Circuits
Disconnect power transistor unit connector. Check continuity at each power transistor unit terminal. (Scheme 8)or (Scheme 9). If continuity is not as specified, replace power transistor.
Scheme 7
Scheme 8
Scheme 9
IDLE SPEED & IGNITION TIMING
Ensure idle speed and ignition timing are set to specification. Improper setting of ignition timing and idle speed may cause driveability problems and/or false setting of trouble codes. For adjustment procedures, see ADJUSTMENTS article.
| Application | (1) Idle RPM | (2) Idle RPM | (3) Maximum CO Level | ||
|---|---|---|---|---|---|
| Altima | (4) 650-750 | (4) 600-700 | 5.0% | ||
| NX & Sentra | |||||
| 1.6L | |||||
| A/T | (4) 750-850 | (4) 675-775 | 7.0% | ||
| M/T | 600-700 | 550-650 | 7.0% | ||
| 2.0L | (4) 750-850 | (4) 700-800 | 10.0% | ||
| Pickup | (4) 750-850 | (4) 700-800 | 5.0% | ||
| 240SX | (4) 650-750 | (4) 600-700 | 7.0% | ||
| (1) With throttle position sensor connected. (2) With throttle position sensor disconnected. (3) Measured in Self-Diagnostic Mode II. (4) Automatic transmission/transaxle in Neutral. | |||||
| (1) | With throttle position sensor connected. |
| (2) | With throttle position sensor disconnected. |
| (3) | Measured in Self-Diagnostic Mode II. |
| (4) | Automatic transmission/transaxle in Neutral. |
4-CYLINDER IDLE SPEED & CO LEVEL
| Application | (1) Idle RPM | (2) Idle RPM | (3) Maximum CO Level | ||
|---|---|---|---|---|---|
| Maxima | |||||
| VE30DE | (4) 650-750 | (4) 650-750 | 0.2-8.0% | ||
| VG30E | (4) 650-750 | (4) 700 | 0.2-8.0% | ||
| Pathfinder & Pickup | (4) 700-800 | (4) 700 | 0.2-8.0% | ||
| Quest | (4) 650-750 | (4) 700-800 | 0.2-8.0% | ||
| 300ZX | |||||
| A/T | |||||
| Non-Turbo | (4) 720-820 | (4) 720 | 0.2-8.0% | ||
| Turbo | (4) 700-800 | (4) 700 | 0.2-8.0% | ||
| M/T | 650-750 | 650 | 0.2-8.0% | ||
| (1) With Auxiliary Air Control (AAC) valve connected. (2) With Auxiliary Air Control (AAC) valve disconnected. (3) Measured in self-diagnostic Mode II. (4) Automatic transmission/transaxle in Neutral. | |||||
| (1) | With Auxiliary Air Control (AAC) valve connected. |
| (2) | With Auxiliary Air Control (AAC) valve disconnected. |
| (3) | Measured in self-diagnostic Mode II. |
| (4) | Automatic transmission/transaxle in Neutral. |
V6 IDLE SPEED & CO LEVEL
| Application | Man. Trans. | (1) Auto. Trans. | |
|---|---|---|---|
| Altima & 240SX | 18-22 @ 700-800 | 18-22 @ 700-800 | |
| NX & Sentra | |||
| 1.6L | 8-12 @ 600-700 | 8-12 @ 800-900 | |
| 2.0L | 13-17 @ 800-900 | 13-17 @ 800-900 | |
| Pickup | 8-12 @ 750-850 | 8-12 @ 750-850 | |
| (1) Automatic transmission/transaxle in Neutral. | |||
| (1) | Automatic transmission/transaxle in Neutral. |
4-CYLINDER IGNITION TIMING (Degrees BTDC @ RPM)
| Application | Man. Trans. | (1) Auto. Trans. | |
|---|---|---|---|
| Maxima, Pathfinder, Pickup & Quest | 13-17 @ 700-800 | 13-17 @ 700-800 | |
| 300ZX | |||
| Non-Turbo | 13-17 @ 650-750 | 13-17 @ 720-820 | |
| Turbo | 13-17 @ 650-750 | 13-17 @ 700-800 | |
| (1) Automatic transmission/transaxle in Neutral. | |||
| (1) | Automatic transmission/transaxle in Neutral. |
V6 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.