Isuzu KB P190. Manual - part 420

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-63

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.

Test Description

The number below refers to the step number on the
Circuit/ System Testing.
5. If the fuel rail pressure (FRP) regulator low side
circuits between the ECM and the FRP regulator are
shorted to ground, FRP Regulator Feedback will be
approximately 400mA lower as compared with normal.

Schematic Reference: Engine Controls Schematics

Connector End View Reference: Engine Controls
Connector End Views or ECM Connector End Views

Circuit/ System Testing Engine Cranks but Does Not Run (1of 2)

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

Install a scan tool.

Turn OFF the ignition for 30 seconds.

Crank the engine for the specified amount of
time.

Monitor the DTC Information with a scan tool.

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

15 seconds

Go to Applicable

DTC

Go to Step 3

Turn OFF the ignition.

Wait 1 minute for the fuel pressure to bleed
down from the fuel rail.

Turn ON the ignition, with the engine OFF. DO
NOT start the engine.

Observe the Fuel Rail Pressure parameter
with a scan tool.

Does the scan tool indicate the specified value?

0 MPa (0 psi)

Go to Step 4

Go to Step 6

Notice: If the vehicle has run out of fuel, air may
be trapped in the fuel system.

Make sure the fuel tank have adequate fuel
and the fuel quality is good (take a sample).

Observe the Fuel Rail Pressure parameter on
the scan tool while cranking over the engine
for 5 seconds.

Does the scan tool indicate more than the specified
value during crank?

20 MPa (2,900

psi)

Go to Step 9

Go to Step 5

Observe the FRP Regulator Feedback parameter
on the scan tool while cranking over the engine for
5 seconds.

Does the scan tool indicate more than the specified
value during crank?

1500 mA

Go to 2 of 2 Step 1

Go to Step 8

6E-64 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Turn OFF the ignition.

Disconnect the FRP sensor harness
connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the FRP sensor (pins 1, 2 and 3
of E-48).

Disconnect the ECM harness connector.

Inspect for an intermittent, for poor
connections and corrosion at the harness
connector of the ECM (pins 47, 48, 68 and 69
of E-90).

Test for high resistance on each circuit.

Repair the connection(s) or circuit(s) as
necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 7

Replace the FRP sensor. Refer to FRP Sensor
Replacement.

Did you complete the replacement?

—

Go to Step 11

—

Repair the short to ground between the ECM (pins
50 and 70 of E-90) and the FRP regulator (pin 2 of
E-50).

Did you compete the repair?

—

Go to Step 11

—

Check for normal readings at key up for the
following sensor inputs: Use the Scan Tool
Data List or a known good vehicle to
determine nominal values.

• Engine Coolant Temperature Sensor

• Barometric Pressure (BARO) Sensor

• Boost Pressure Sensor

• Intake Throttle Position Sensor

Repair the circuit(s) or replace the sensor as
necessary.

Did you find and correct the condition?

—

Go to Step 11

Go to Step 10

Other possible causes for the no-start
condition:

• Engine mechanical timing

• Heavily restricted intake or exhaust

plugged solid.

• Poor engine compression.

• Water or gasoline contamination in fuel.

Repair as necessary.

Did you find and correct the condition?

—

Go to Step 11

—

Reconnect all previously disconnected
harness connector(s).

Turn OFF the ignition for 30 seconds.

Attempt to start the engine.

Does the engine start and continue to run?

—

Go to Step 12

Go to Step 2

Observe the DTC Information with a scan tool.

Are there any DTCs that you have not diagnosed?

—

Go to DTC List

System OK

Step

Action

Value(s)

Yes

ENGINE CONTROL SYSTEM (4JK1/4JJ1) 6E-65

Circuit/ System Testing Engine Cranks but Does Not Run (2 of 2)

Step

Action

Value(s)

Yes

Remove the engine cover.

Perform the Injector Force Drive with a scan
tool.

Command each injector ON and verify clicking
noise (solenoid operating noise).

Is there an injector that does not create a clicking
noise (solenoid operating noise), contains an
interrupted noise or abnormal noise when
commanded ON?

—

Go to Step 8

Go to Step 2

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

• 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.

Repair any fuel system leaks as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 3

Check 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.

Repair or replace as necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 4

6E-66 ENGINE CONTROL SYSTEM (4JK1/4JJ1)

Notice: Make sure the in-tank fuel pump operation
before performing the following procedures. Refer
to In-tank Fuel Pump System Check in this section.

Turn OFF the ignition.

Disconnect the fuel hose from the fuel supply
pump suction side. In order to measure the
discharged fuel amount, put the hose into a
bottle or a container with a scale. (The inlet of
a bottle or a container must be larger than the
diameter of hose.)

Turn ON the ignition for 20 seconds, with the
engine OFF.

Turn OFF the ignition for 10 seconds.

Perform 3 and 4 three times. The accumulated
fuel of three ignition cycles must be more than
300 cc. (Normal amount is more than 100 cc
per one ignition cycle.)

Notice: If there is a leak or a restriction on the
suction side, the fuel from the hose will not flow out
sufficiently that is most likely caused by fuel
leakage, clogged fuel filter, kinked or crushed fuel
hose or pipe. Also inside the fuel tank for any
foreign materials may be getting drawn into the fuel
line pickup.

Repair fuel system leaking or restrictions as
necessary.

Did you find and correct the condition?

—

Go to Step 12

Go to Step 5

Turn OFF the ignition.

Remove the Fuel Pump (10A) fuse from the
engine room fuse block in order to disable in-
tank fuel pump.

Disconnect each fuel injector harness
connector from all fuel injectors in order to
disable injection.

Remove the rubber fuel hose from the leak-off
pipe. Then, remove the leak-off pipe assembly
from the engine that is jointed to the fuel
supply pump and the pressure limiter valve.
Use a pan to catch the fuel from the removed
fuel line.

Crank over the engine while observing the fuel
leak from the pressure limiter valve.

Important: Safety glasses must be worm. Fuel
may splash if the pressure limiter valve is faulty.

Is there fuel leak from the pressure limiter valve?

—

Go to Step 11

Go to Step 6

Step

Action

Value(s)

Yes

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