Nissan Altima (L32) 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:
P1778 step motor - function
Description
• The step motor's 4 aspects of ON/OFF change according to the signal from
TCM. As a result, the flow of line
pressure to primary pulley is changed and pulley ratio is controlled.
• This diagnosis item is detected when electrical system is OK, but mechanical
system is NG.
...
Front tweeter (coupe)
Description
The audio unit sends audio signals to the BOSE speaker amp. The BOSE speaker
amp. amplifies the audio
signals before sending them to the front tweeters using the audio signal
circuits.
Diagnosis Procedure
1.HARNESS CHECK
1. Disconnect BOSE speaker amp. connector B122 and suspe ...
Center speaker
Description
The audio unit sends audio signals to the BOSE speaker amp. The BOSE speaker
amp. amplifies the audio
signals before sending them to the center speaker using the audio signal
circuits.
Diagnosis Procedure
1.HARNESS CHECK
1. Disconnect BOSE speaker amp. connector B121 and cente ...