Isuzu N 2008 Series Workshop Manual page 87

1A-84 Engine Control System (4JJ1)
Step
1. Inspect the high pressure side between the
fuel supply pump and the fuel injectors for fuel
leakage. The following components may
contain an external leak.
• Fuel supply pump
• Fuel rail
• Pressure limiter valve
• Fuel rail pressure (FRP) sensor
• Fuel pipe between the fuel supply pump
and fuel rail
• Fuel pipe between the fuel rail and fuel
injectors
2
• Each fuel pipe sleeve nuts
Notice: Fuel may leak under the cylinder head
cover from the inlet high pressure line. In such
case, the engine oil level will rise. Inspect for
fuel leakage into the engine oil.
Notice: Remove and inspect the inlet high
pressure joint to the fuel injectors for fuel
leaking from the sleeve nut(s). Replace the
fuel injector and injection pipe when foreign
material was in contact.
2. Repair any fuel system leaks as necessary.
Did you find and correct the condition?
1. Remove each glow plug from the cylinder
head.
2. Inspect for fuel leakage into the combustion
3
chamber.
Is there a cylinder that fuel leakage into the
combustion chamber?
1. Install a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4
4. Monitor the DTC Information with a scan tool.
Is DTC P0087, P0091, P0092, P0192, P0193,
P0201 - P0204, P2146 or P2149 set?
1. Turn OFF the ignition.
2. Wait 1 minute for the fuel pressure to bleed
down from the fuel rail.
3. Turn ON the ignition, with the engine OFF.
5
4. Observe the FRP Sensor parameter with the
scan tool.
Does the scan tool indicate within the specified
value?
1. Place the transmission in Neutral and set the
parking brake.
2. Start the engine.
3. Perform the Cylinder Balance Test with a scan
tool.
6
4. Command each injector OFF and verify an
engine speed change for each injector.
Is there an injector that does not change engine
speed when commanded OFF?
Action Value(s)
—
Go to Step 19
—
Go to Step 16
—
Go to Applicable
0.9 to 1.0 volt
Go to Step 6
—
Go to Step 17
Yes No
Go to Step 3
Go to Step 4
DTC Go to Step 5
Go to Step 13
Go to Step 7