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: 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 valve c ...

    Other materials:

    P0447 Evap canister vent control valve
    Description The EVAP canister vent control valve is located on the EVAP canister and is used to seal the canister vent. This solenoid valve responds to signals from the ECM. When the ECM sends an ON signal, the coil in the solenoid valve is energized. A plunger will then move to seal the ca ...

    B2555 stop lamp
    Description BCM detects the stop lamp status and confirms the stop lamp switch ON/OFF status. BCM confirms the engine start condition according to the stop lamp switch ON/OFF status. DTC Logic DTC DETECTION LOGIC DTC CONFIRMATION PROCEDURE 1.PERFORM DTC CONFIRMATION PROCEDURE 1. Depress ...

    P0506 ISC System
    Description The ECM controls the engine idle speed to a specified level through the fine adjustment of the air, which is let into the intake manifold, by operating the electric throttle control actuator. The operating of the throttle valve is varied to allow for optimum control of the engine ...