Nissan Altima 2007-2012 Service Manual: Compression pressure

On-Vehicle Service

CHECKING COMPRESSION PRESSURE

1. Run the engine until it reaches normal operating temperature.

2. Turn the ignition switch to OFF.

3. Release fuel pressure and leave the fuel pump electrically disconnected.

Refer to EC-1579, "Inspection".

4. Remove all six spark plugs.

Refer to EM-119, "Removal and Installation".

5. Attach a compression tester to No. 1 cylinder.

6. Depress accelerator pedal fully to keep the electric throttle control actuator butterfly-valve wide open to maximize air intake flow.

7. Crank the engine and record the highest gauge indication

8. Repeat the measurement on each cylinder (steps 5 - 7).

• Always use a fully-charged battery to obtain specified engine speed.


9. If compression in one or more cylinders is low:


9. If compression in one or more cylinders is low: a. Pour a small amount of engine oil into cylinders through the spark plug holes.

b. Retest compression (steps 5 - 8).

• If adding oil helps raise compression pressure, then the piston rings may be worn or damaged. If so, replace piston rings after checking piston.

• If the pressure stays low, a valve may be sticking or is seating improperly. Inspect and repair the valve and/or valve seat. Refer to EM-229, "Camshaft". If the valve and/or valve seat is damaged excessively, replace as necessary.

• If compression stays low in two or more cylinders that are next to each other: - The cylinder head gasket may be leaking.

- Both cylinders may have valve component damage. Inspect and repair as necessary.

    Camshaft valve clearance
    Valve Clearance CHECKING • Perform inspection as follows after removal, installation or replacement of camshaft or valve related parts, or if there is unusual engine conditions regarding valv ...

    Other materials:

    Pre-inspection for diagnostic
    Basic Inspection The engine start function, door lock function, power distribution system and NATS-IVIS/NMS in the Remote Keyless Entry system are closely related to each other regarding control. Narrow down the functional area in question by performing basic inspection to identify which func ...

    P0461 fuel level sensor
    Description The fuel level sensor is mounted in the fuel level sensor unit. The sensor detects a fuel level in the fuel tank and transmits a signal to the combination meter. The combination meter sends the fuel level sensor signal to the ECM through CAN communication line. It consists of ...

    U1000 Can comm circuit
    Description Refer to AV-240, "System Description". DTC Logic DTC DETECTION LOGIC Diagnosis Procedure Symptom: Displays “CAN COMM CIRCUIT [U1000]” as a self-diagnosis result of AV control unit. 1.CHECK CAN COMMUNICATION Select “SELF-DIAG RESULTS” mode for †...