Isuzu 4JA1 Workshop Manual page 303

Step
7 1. Disconnect the fuel hose that connects to the
fuel injection pump suction side. In order to
measure the discharged fuel amount, put the
hose into a bottle or a container.
2. Pump the priming pump on the fuel filter.
Notice: If there is a leak on the suction side of the
fuel system, the fuel from the disconnected hose will
not flow out sufficiently and fuel leakage may occur.
Also if there is a restriction on the suction side of the
fuel system, the fuel from the disconnected hose will
not flow out sufficiently that is most likely caused by
clogged fuel filter or kinked fuel hose or pipe.
3. Draw fuel from the fuel tank at the fuel line (as
close to the fuel tank as possible) going to the
fuel pickup tube to verify a clean stream of fuel
comes out (use the hand-held vacuum pump 5-
8840-0279-0/J-23738-A with a clear hose or
equivalent). This will ensure the fuel pickup tube
is not cracked drawing air into the fuel line.
4. Repair any fuel system leaks and restrictions as
necessary.
Did you find and correct the condition?
8 1. Other possible causes for the no-start condition:
•
Fuel injection pump mechanical timing
incorrect
•
Flywheel installed incorrectly causing the
crankshaft position (CKP) sensor to be
incorrectly timed to the engine. Disconnect
sensor and attempt to start engine to verify
•
Heavily
catalytic converter plugged solid
•
Poor engine compression
•
Water or gasoline contamination in fuel
2. Repair or replace as necessary.
Did you find and correct the condition?
9 Important: The fuel injection pump must be timed to
the engine.
Replace the fuel injection pump. Refer to Fuel
Injection Pump Replacement in engine mechanical
section.
Did you complete the replacement?
10 1. Reconnect all previously disconnected harness
connector(s).
2. Turn OFF the ignition for 30 seconds.
3. Attempt to start the engine.
Does the engine start and continue to run?
11 Observe the DTC Information with the scan tool.
Are there any DTCs that you have not diagnosed?
Action
restricted intake, exhaust
Engine Control System (4JH1) 6E-49
Value(s)


or


Go to Diagnostic

Trouble Code (DTC)
Yes
Go to Step 10 Go to Step 8
Go to Step 10 Go to Step 9
Go to Step 10
Go to Step 11 Go to Step 2
List System OK
No
