Nissan Frontier D40. Manual - part 601

EM-136

< ON-VEHICLE MAINTENANCE >

[VQ40DE]

COMPRESSION PRESSURE

COMPRESSION PRESSURE

Compression Pressure

INFOID:0000000005274324

CHECKING COMPRESSION PRESSURE

1.

Warm up engine thoroughly. 

2.

Release fuel pressure. Refer to 

EC-954, "Fuel Pressure Check"

.

3.

Disconnect fuel pump fuse to avoid fuel injection during mea-
surement.

4.

Remove intake manifold collector. Refer to 

EM-140, "Removal and Installation"

.

5.

Remove spark plug from each cylinder. Refer to 

EM-130, "Removal and Installation"

.

6.

Connect engine tachometer (not required in use of CONSULT-III).

7.

Install compression tester with adapter onto spark plug hole.

• Use compression gauge whose pick up end inserted to spark

plug hole is smaller than 20 mm (0.79 in) in diameter. Other-
wise, it may be caught by cylinder head during removal.

8.

Turn ignition switch to “START” for cranking. When the gauge pointer stabilizes, read the compression
pressure and engine rpm. Perform these steps to check each cylinder.

Compression pressure:

Unit: kPa (kg/cm

2

, psi) /rpm

CAUTION:

Always use a fully charged battery to obtain specified engine speed.
• If the engine speed is out of the specified range, check the battery liquid for proper gravity. Check the

engine speed again with normal battery gravity. 

BBIA0534E

PBIC0900E

SBIA0533E

Standard

Minimum

Differential limit between cylinders

 1,275 (13.0, 185) / 300

981 (10.0, 142) / 300

98 (1.0, 14) / 300

COMPRESSION PRESSURE

EM-137

< ON-VEHICLE MAINTENANCE >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

• If the compression pressure is below the minimum value, check the valve clearances and parts associ-

ated with the combustion chamber (valve, valve seat, piston, piston ring, cylinder bore, cylinder head,
cylinder head gasket). After the checking, measure the compression pressure again.

• If some cylinders have low compression pressure, pour a small amount of engine oil into the spark plug

hole of the cylinder to re-check it for compression.

• If the added engine oil improves the compression, piston rings may be worn out or damaged. Check the

piston rings and replace if necessary.

• If the compression pressure remains at low level despite the addition of engine oil, the valves may be

malfunctioning. Check the valves for damage. Replace the valve or valve seat accordingly.

• If two adjacent cylinders have respectively low compression pressure and their compression remains

low even after the addition of engine oil, cylinder head gaskets may be leaking, or a valve in adjacent
cylinders may be damaged. Inspect and repair as required.

9.

Install the components in the reverse order of removal.

10. Start the engine, and confirm that it runs smoothly.

11. Perform trouble diagnosis. If DTC appears, erase it. Refer to 

EC-538, "Description"

.

EM-138

< ON-VEHICLE REPAIR >

[VQ40DE]

ENGINE ROOM COVER

ON-VEHICLE REPAIR

ENGINE ROOM COVER

Removal and Installation

INFOID:0000000005274325

CAUTION:

Do not damage or scratch cover when installing or removing. 

REMOVAL

1.

Remove the engine room cover bolts using power tool.

2.

Lift up on engine cover firmly to dislodge snap fit mounts.

INSTALLATION

Installation is in the reverse order of removal.

WBIA0622E

AIR CLEANER AND AIR DUCT

EM-139

< ON-VEHICLE REPAIR >

[VQ40DE]

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

AIR CLEANER AND AIR DUCT

Exploded View

INFOID:0000000005274326

Removal and Installation

INFOID:0000000005274327

CAUTION:

Handle mass air flow sensor with care.
• Do not shock it.
• Do not disassemble it.
• Do not touch its sensor.
NOTE:
Add marks as necessary for easier installation.

REMOVAL

1.

Remove the engine room cover using power tool. Refer to 

EM-138, "Removal and Installation"

.

2.

Disconnect the harness connector from air cleaner case (upper).

3.

Remove the air duct and resonator assembly and air cleaner case (upper).

4.

Remove air cleaner filter and air cleaner case (lower).

INSPECTION AFTER REMOVAL

Inspect air duct and resonator assembly for cracks or tears.
• If anything found, replace air duct and resonator assembly.

INSTALLATION

Installation is in the reverse order of removal.

1.

Air cleaner case (lower)

2.

Air cleaner filter

3.

Air cleaner case (upper)

4.

Air duct and resonator assembly

Front

AWBIA0133GB