Isuzu KB P190. Manual - part 270

6E-46 Engine Control System (4JH1)

Step Action

Value(s)

Yes

1.  Turn OFF the ignition.
2.  Reconnect all disconnected connectors.
3.  Turn the ignition ON with the engine OFF.
4.  Attempt to establish scan tool communications

with the ECM.

Does the scan tool communicate with the ECM?



System OK

Go to Step 3

Engine Control System (4JH1) 6E-47

Engine Cranks but Does Not Run

Description
The Engine Cranks but Does Not Run diagnostic table
is an organized approach to identifying a condition that
causes an engine to not start. The diagnostic table
directs the service technician to the appropriate system
diagnosis. The diagnostic table assumes the following
conditions are met:

• The battery is completely charged and terminals

are cleaned and tight.

•  The engine cranking speed is normal.
•  There is adequate fuel in the fuel tank.
•  There is no fuel leak in the fuel line.
•  There is no air in the fuel line.
•  Filters (Air, Fuel) are clean.
•  Fuse and slow blow fuse are normal.

Diagnostic Aids

• If an intermittent condition is suspected, refer to

Intermittent Conditions in this section.

Step Action

Value(s)

Yes

Did you perform the Diagnostic System Check-
Engine Controls?



Go to Step 2

Go to Diagnostic

System Check-

Engine Controls

1.  Install the scan tool.
2.  Turn OFF the ignition for 30 seconds.
3.  Crank the engine for specified amount of time.
4. Monitor the Diagnostic Trouble Code (DTC)

Information with the scan tool.

Does the scan tool display any DTCs that failed this
ignition?

15 seconds

Go to Diagnostic

Trouble Code (DTC)

List

Go to Step 3

1. Check for normal readings at key up for the

following inputs and output: Refer to the scan
tool Data List or a known good vehicle to
determine normal values.

•  System Voltage
•  Engine Coolant Temperature (ECT)
•  Intake Air Temperature (IAT)
•  Mass Air Flow (MAF) Sensor
•  Barometric Pressure
•  Desired Injection Quantity

2. Repair or replace as necessary.
Did you find and correct the condition?



Go to Step 10

Go to Step 4

6E-48 Engine Control System (4JH1)

Step Action

Value(s)

Yes

1. Inspect the high pressure side between the fuel

injection pump and the fuel injection nozzles for
fuel leakage. The following components may
contain an external leak.

•  Fuel injection pump
•  Fuel injection pump control unit (PCU)
•  Fuel injection solenoid valve
•  Timing control valve (TCV)
•  Constant pressure valve (CPV)
•  Fuel pipe between the fuel injection pump

and fuel injection nozzles

• Each fuel pipe sleeve nuts
• Each fuel pipe connectors
• Each

gaskets

Notice: Fuel may leak into the engine from the fuel
injection pump. In such case, the engine oil level will
rise. Inspect for fuel leakage into the engine oil.
2. Repair any fuel system leaks as necessary.
Did you find and correct the condition?



Go to Step 10

Go to Step 5

1. Turn OFF the ignition.
2. Check the fuel system line connections between

the fuel tank and the fuel injection pump for
tightness and all fuel hoses for cuts, cracks and
for the use of proper clamps.

3. Pump the priming pump on the fuel filter until it

becomes firm. If there is a leak on the suction
side of the fuel system between the priming
pump and the fuel injection pump, the priming
pump will not build up sufficient firmness and fuel
leakage may occur.

4. Repair or replace as necessary.
Did you find and correct the condition?



Go to Step 10

Go to Step 6

1. Remove the fuel hose that connects to the fuel

injection pump suction side.

2. Remove the fuel pipe connector that connects to

the fuel injection pump suction side.

3. Inspect the eye bolt for any type of restriction or

collapsed gauze filter.

Notice: If any type of restriction found, check for a
condition that causes contaminated fuel, such as the
customer is using an aftermarket fuel filter or
extended maintenance interval.Also inspect fuel
waxing or icing that is caused by an incorrect fuel
type used in winter season or water intrusion in the
fuel system.
4. Repair or replace as necessary.
Did you find and correct the condition?



Go to Step 10

Go to Step 7

Engine Control System (4JH1) 6E-49

Step Action

Value(s)

Yes

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?



Go to Step 10

Go to Step 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 restricted intake, exhaust or

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?



Go to Step 10

Go to Step 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?



Go to Step 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?



Go to Step 11

Go to Step 2

Observe the DTC Information with the scan tool.
Are there any DTCs that you have not diagnosed?



Go to Diagnostic

Trouble Code (DTC)

List System

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