Isuzu KB P190. Manual - part 601

6E–234

ENGINE DRIVEABILITY AND EMISSIONS

12

Visually/physically inspect the secondary ignition
wires. Check for the following conditions:

• Verify that all ignition wire resistance are less than

the specified value.

• Verify that ignition wires are correctly routed to

eliminate cross-fitting.

• Verify that ignition wires are not arcing to ground.

Spraying the secondary ignition wires with a light
mist of water may help locate an intermittent
problem.

Was a problem found?

#1 cyl. 4.4k

Ω

#2 cyl. 3.6k

Ω

#3 cyl. 3.1k

Ω

#4 cyl. 2.8k

Ω

Verify repair

Go to Step 13

13

1. Disconnect the spark plug high tension cable from

No.1 spark plug.

2. Install a spark tester at the end of the

disconnected ignition coil.

3. Clip the spark tester to a good ground.

4. Observe the spark tester while the engine is

cranking.

Was a crisp blue spark observed? (Only one or two
sparks followed by no result is considered the same
as “No Spark”.)

—

Go to Step 21

Go to Step 14

14

1. Disconnect the ignition coil harness connector.

2. Check for an open or short circuit between the

ignition coil and the ECM.

Was a problem found?

—

Verify repair

Go to Step 15

15

1. Ignition “On”.

2. Using a Digital Voltmeter (DVM) check the ignition

wire coil at the ignition coil harness connector.

Was the voltage equal to the specified value?

Battery 
voltage

Go to Step 16

Verify repair

16

1. Ignition “Off”.

2. With DVM, check for an open in the ground wire at

the ignition coil harness connector.

Was the ground wire OK?

—

Go to Step 17

Verify repair

17

Replace the ignition coil, verify the repair.
Attempt to start the engine.
Is there still a problem?

—

Go to Step 18

Verify repair

18

Use an ohmmeter to check the ignition coil primary
winding resistance.
Was the primary winding resistance approximately
equal to the specified value?

0.8-18k

Ω

Go to Step 19

Go to Step 20

19

Use an ohmmeter to check the ignition coil secondary
winding resistance.
Was the primary winding resistance hear around the
to the specified value?

2.5k

Ω

Go to Step 21

Go to Step 20

20

Replace the ignition coil.

—

Verify repair

—

21

1. Remove the spark plugs from all cylinders.

2. Visually inspect the spark plug electrodes.

3. Replace any spark plugs with loose or missing

electrodes or cracked insulators.

Did your inspection reveal any spark plugs exhibiting
excessive fouling?

—

Correct the 

fouling 

condition

Go to Step 22

Step

Action

Value(s)

Yes

No

ENGINE DRIVEABILITY AND EMISSIONS

6E–235

22

Perform the procedure in Fuel System Pressure Test
(Refer to 6E-108  “Fuel System Diagnosis”) to
determine if there is a problem with fuel delivery.
Was a problem found?

—

Verify repair

Go to Step 23

23

Refer to 6E-108 page  “Fuel System Diagnosis”

 to

determine if there is a problem with fuel delivery.
Was a problem found?

—

Verify repair

Go to Step 24

24

Check for the following engine mechanical problems
(refer to Engine Mechanical):

• Low compression

• Leaking cylinder head gaskets

• Worn camshaft

• Camshaft drive belt slipped or stripped
Was a problem found?

—

Verify repair

Go to Step 25

25

1. Review all diagnostic procedures within this table.

2. If all procedures have been completed and no

malfunctions have been found, review/inspect the
following:

• Visual/physical inspection

• Tech 2 data

• All electrical connections within a suspected

circuit and/or system

Was a problem found?

—

Verify repair

Go to Step 26

26

Is the ECM programmed with the latest software
release? 
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”. 
Was the problem solved?

—

Verify repair

Go to Step 27

27

Replace the ECM. 
Is the action complete? 
IMPORTANT:  The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual. 
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.

—

Verify Repair

—

Step

Action

Value(s)

Yes

No

6E–236

ENGINE DRIVEABILITY AND EMISSIONS

HARD START SYMPTOM

DEFINITIONS: Engine cranks, but does not start for a long time. Does eventually start, of may start and then
immediately stall.

Step

Action

Value(s)

Yes

No

1

Was the “On-Board Diagnostic (OBD) System Check”
performed?

—

Go to Step 2

Go to OBD 

System Check

2

1. Perform a bulletin search.

2. If a bulletin that addresses the symptom is found,

correct the condition as instructed in the bulletin.

Was a bulletin found that addresses the symptom?

—

Verify repair

Go to Step 3

3

Was a visually/physical check performed?

—

Go  to  Step 4

Go to Visual / 

physical Check.

4

1. Visually/physically inspect for the following

conditions:

• Restriction of air intake system. Check for a

restricted air filter element, or foreign objects
blocking the air intake system

• Check for objects blocking the IAC passage or

throttle bore, excessive deposits in the throttle
bore and on the throttle plate

• Check for a condition that causes a large

vacuum leak, such as an incorrectly installed or
faulty crankcase ventilation hose/brake booster
hose.

Was a problem found?

—

Verify repair

Go to Step 5

5

1. Using a Tech 2, display the IAC value.

2. Check for a faulty, plugged, or sticking IAC

operation.

Was the problem found?

—

Verify repair

Go to Step 6

6

Check engine coolant temperature (ECT) sensor for
shift in value.

1. After 8 hours with hood up and the engine not

running, connect the Tech 2.

2. Ignition On, engine not running.

3. Using Tech 2, compare Engine Coolant

Temperature to Intake Air Temperature.

Are ECT and IAT within the specified value of each
other?

 

±5°C

Go to Step 8

Go to Step 7

ENGINE DRIVEABILITY AND EMISSIONS

6E–237

7

1. Using a Tech 2, display the engine coolant

temperature and note the value.

2. Check the resistance of the engine coolant

temperature sensor.

Is the actual resistance near the resistance value in
the chart for the temperature that was noted?

—

Go  to  Step 8

Replace the 

ECT sensor. 

Verify repair

8

1. Using a Tech 2, display the MAP sensor value in

comparison with atmosphere temperature.

2. Check for a faulty, plugged, or incorrectly installed

MAP sensor.

Was the problem found?

—

Verify repair

Go to Step 9

9

Visually/physically inspect all spark plug high-tension
cables. Check for the following conditions: 

• Verify that the resistance of all spark plug high-

tension cables are less than the specified value. 

• Verify that the all spark plug high-tension cables are

correctly fitted to eliminate cross-fitting. 

• Verify that the all spark plug high-tension cables are

not arcing to ground. 
Spraying the spark plug high-tension cables with a
light mist of water may help locate an intermittent
problem. 

Was a problem found?

#1 cyl. 4.4k

Ω

#2 cyl. 3.6k

Ω

#3 cyl. 3.1k

Ω

#4 cyl. 2.8k

Ω

Verify repair

Go to Step 10

10

Check for proper ignition voltage output with a spark
tester.
Was the problem found?

—

Verify repair

Go to Step 11

11

1. Remove the spark plugs and check for gas or oil

fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.

2. If spark plugs are fouled, the cause of fouling must

be determined before replacing the spark plugs.

Was a problem found?

—

Verify repair

Go to Step 12

12

Check for a loose ignition control module ground.
Was a problem found?

—

Verify repair

Go to Step 13

13

1. Check the ignition coil secondary resistance.

2. Replace the coil if it is greater than the specified

resistance.

Did the coil require replacement?

2.5k

Ω

Verify repair

Go to Step 14

Step

Action

Value(s)

Yes

No

Temperature (°C)

Resistance (

Ω) (Approximately)

-20

26740

0

9120

20

3500

40

1464

60

664

80

333

100

175

120

102