Isuzu engine C22NE / 22LE / 20LE. Manual — part 70

DRIVEABILITY AND EMISSIONS 6E1-109

Engine Cranks But Will Not Run (Cont'd)

Step

Action

Value(s)

Yes

No

7

1. Disconnect the ignition secondary wire at the No.1.

2. Install a spark tester (Use commercially available tool)

at the end of the disconnected ignition coil.

3. Clip the spark tester (Use commercially available tool)

to a good ground (not near the battery).

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 16

Go to Step 8

8

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?

-

Go to Step 9

Go to Step 10

9

Repair the faulty circuit.

-

Verify repair

-

10

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?

B+

Go to Step 12

Go to Step 11

11

Repair the open circuit.

-

Verify repair

-

12

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 14

Go to Step 13

13

Repair the faulty wire.

-

Verify Repair

-

14

Replace the ignition coil, verify the repair.

Attempt to start the engine.

Is there still a problem?

-

Go to Step 15

Verify repair

15

Replace the EPROM or ECM.

-

Verify repair

-

16

Use an ohmmeter to check the ignition coil primary

winding resistance.

Was the primary winding resistance approximately equal

to the specified value?

0.8-18

Ω

Go to Step 17

Go to Step 18

17

Use an ohmmeter to check the ignition coil secondary

winding resistance.

Was the secondary winding resistance hear arround the to

the specified value?

2.5k

Ω

Go to Step 19

Go to Step 18

18

Replace the ignition coil.

-

Verify repair

-

19

Test the resistance of the coil-to-spark plug secondary

ignition wire.

Was the resistance greater than the specified value?

#1 cyl. 4.7k

Ω

#2 cyl. 3.9k

Ω

#3 cyl. 3.4k

Ω

#4 cyl. 3.1k

Ω

Go to Step 20

Go to Step 21

20

Replace the coil-to-spark plug secondary ignition wire and

any other secondary wires which exceed the specified

value.

Is there still a problem?

#1 cyl. 4.7k

Ω

#2 cyl. 3.9k

Ω

#3 cyl. 3.4k

Ω

#4 cyl. 3.1k

Ω

Go to Step 21

Verify repair

6E1-110 DRIVEABILITY AND EMISSIONS

Engine Cranks But Will Not Run (Cont'd)

Step

Action

Value(s)

Yes

No

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

excessing fouling?

-

.

Correct the

fouling

condition

Go to Step 33

22

Verify repair.

Attempt to start the engine.

Is there still a problem?

-

Go to Step 23

Go to Step 22

23

1. Ignition OFF install a fuel pressure gauge at the test

fitting on the fuel supply line in the engine

compartment.

Caution: Use a shop cloth to absorb any fuel leakage

while making the connection.

2. Check the engine and observe the fuel pressure.

Is the fuel pressure within the specified values, and does it

hold steady for 2 seconds?

285-375 kPa

(43-55 psi)

Go to Step 25

Go to Step 24

24

Is any fuel pressure indicated?

-

Go to Fuel

System

Electrical

Test

Go to Fuel

System

Diagnosis

25

1. Install switch box Injector Adaptor Cable 5-8840-2589-

0 and Fuel Injector Tester 5-8840-2618-0 to the injector

connector.

2. Activate an injector.

Did the fuel pressure drop when the injector was

activated?

-

Go to Step 26

Go to Fuel

System

Diagnosis

26

Pressurize the fuel system using the ignition ON and

switch the injector connector to test pressure drop for

each injector.

Was there a pressure drop when each injector was

activated?

-

Go to Step 27

Go to Fuel

System

Diagnosis

27

1. Remove all SST and re-assemble the all connectors

and fuel hoses to original position.

2. Crank the engine.

Does the engine start smoothly?

-

Go to Step 33

Go to Step 28

28

1. Raise the vehicle and disconnect the CKP sensor

harness.

2. Ignition ON.

3. With a test light to ground, probe the CKP ignition feed

harness terminal.

Did the light illuminate?

-

Go to Step 29

Go to Step 30

29

1. Ignition ON.

2. At the CKP harness connector, connect a test lamp

between the ignition and ground terminals.

Did the lamp illuminate?

-

Go to Step 31

Go to Step 32

DRIVEABILITY AND EMISSIONS 6E1-111

Engine Cranks But Will Not Run (Cont'd)

Step

Action

Value(s)

Yes

No

30

Check the CKP High circuit between the sensor and the

ECM for a short to ground or open circuit.

Was a problem found?

-

Verify Repair

Go to Step 33

31

Replace the CKP position sensor.

Is there still a problem?

-

Go to Step 34

-

32

Check the CKP Low circuit between the sensor and the

ECM for: an open circuit, a short to ground, or short to

voltage. Was the problem found?

-

Verify Repair

Go to Step 33

33

Replace the EPROM or ECM.

Note) Refer to 6E-243

-

Verify Repair

-

34

1. Test the fuel for contamination.

2. If a problem is found, clean the fuel system and correct

the contaminated fuel condition as necessary. Replace

the fuel filter and replace any injectors that are not

delivering fuel (see Injector Balance Test).

Was a problem found?

-

Verify repair

Go to Step 35

35

Refer to Engine Mechanical Diagnosis to diagnose the

following conditions:
• Slipped camshaft drive belt.
• Leaking or sticky valves or rings.
• Excessive valve deposits.
• Loose or worn rocker arms.
• Weak valve springs.
• Leaking head gasket.
Is the action complete?

-

Verify repair

-

6E1-112 DRIVEABILITY AND EMISSIONS