Isuzu 2008MY N Series Workshop Manual page 95

1A-92 Engine Control System (4HK1)
Step
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?
1. Inspect the fuel system line connections
between the fuel tank and the fuel supply
pump for tightness and all fuel hoses for cuts,
cracks and for the use of proper clamps.
Notice: The fuel system from the fuel tank(s)
to the fuel supply pump is under a slight
vacuum with the engine running. As a result,
air can enter the fuel system if these
connections are not tight. Air in the fuel
system
fluctuations especially at high engine speed
and load, which may set this DTC.
7
2. Pump the priming pump until it becomes firm.
If there is a leak on the suction side of the fuel
system between the priming pump and the
fuel supply pump, the priming pump will not
build up sufficient firmness and fuel leakage
may occur.
3. Start the engine and check for high side fuel
system leaks at the fuel supply pump and fuel
rail.
4. Repair any fuel system leaks as necessary.
Did you find and correct the condition?
Action
will cause fuel rail
Value(s)
—
pressure
—
Yes
Go to Step 17 Go to Step 7
Go to Step 19 Go to Step 8
No