Isuzu 4JB1TC User Manual

SERVICE INFORM
ATION 00 – 3
1.
HARD STARTING
1. STARTER INOPERATIVE
Checkpoint Possible cause Correction
Loos
e battery cable terminal poor
connections due to rusting
Clean and/or retighten the battery
cable terminal
Batter
y discharged or weak Recharge or replace the battery
Battery
F
an belt loose or broken Adjust or replace the fan belt
F
usible link Fusible link shorted Replace the fusible link
Star
ter switch Defective starter switch or starter relay Replace the starter switch or the
Starter relay
Def
ective magnetic switch or starter relay Repair or replace the magnetic switch
Starter m
otor
Defective starter motor Repair or replace the starter motor
2. STARTER MOTOR OPERATES BUT ENGINE DOES NOT TURN OVER
Loos
e battery cable terminal Clean and/or retighten the battery
cable terminal
Poor
connections due to rusting Recharge or replace the battery
Batter
y discharged or weak Recharge or replace the battery
Battery
F
an belt loose or broken Adjust or replace the fan belt
Def
ective pinion gear Replace the pinion gear
Def
ective magnetic switch Repair or replace the magnetic switch
Star
ter
Brush wear, Weak brush spring Replace the brush and/or the brush
spring
Engine
Piston, crank bearing seizure, or other
damage
Repair or replace the related parts

Isuzu 4JB1TC Specifications

General

Aspiration	Turbocharged
Displacement	2.8 L (2771 cc)
Fuel System	Direct injection
Bore x Stroke	93 mm x 102 mm
Cooling System	Water-cooled
Starting System	Electric starter
Max Power RPM	3600 rpm
Engine Type	4-Cylinder, In-Line, OHV

Summary

1. HARD STARTING

1. STARTER INOPERATIVE

Troubleshooting for a starter that fails to operate, covering battery, fusible link, and starter switch/motor.

2. STARTER MOTOR OPERATES BUT ENGINE DOES NOT TURN OVER

Troubleshooting steps when the starter motor runs but the engine doesn't engage.

3. ENGINE TURNS OVER BUT DOES NOT START

FUEL IS NOT BEING DELIVERED TO THE INJECTION PUMP

Diagnosing issues where fuel is not reaching the injection pump, covering tank, lines, and filter.

FUEL IS BEING DELIVERED TO THE INJECTION PUMP

Troubleshooting when fuel is delivered but the engine still won't start, focusing on fuel quality and injection components.

4. QUICK-ON START SYSTEM

GLOW PLUGS ARE RECEIVING POWER

Procedures for diagnosing glow plug system issues when power is supplied.

GLOW PLUGS ARE NOT RECEIVING POWER

Procedures for diagnosing glow plug system issues when no power is supplied.

6. OVERHEATING

Cooling System Components and Timing

Troubleshooting cooling water, radiator, pump, thermostat, and injection timing for overheating.

Airflow and Drive Belts

Diagnosing fan clutch, fan belt, and airflow issues causing engine overheating.

9. OIL PRESSURE DOES NOT RISE

Oil Supply and Filtration

Oil Pressure Monitoring and Relief Systems

Lubrication System Wear Points

10. ABNORMAL ENGINE NOISE

1. ENGINE KNOCKING

2. GAS LEAKAGE NOISE

3. CONTINUOUS NOISE

11. ENGINE COOLING TROUBLE

Engine Overheating

Procedures for diagnosing and resolving engine overheating issues.

Engine Overcooling and Warm-up Issues

12. ENGINE ELECTRICAL PART TROUBLE

Starter Does Not Run

Troubleshooting steps for a starter motor that fails to operate.

13. TURBOCHARGER

Engine Has Less Than Normal Power

Blue or Black Smoke

Excessive Oil Consumption

Excessive Turbocharger Noise

Excessive Rotating Part Wear

QUICK-ON START II SYSTEM (4JB1 / 4JB1T / 4JB1TC only)

QUICK-ON START III SYSTEM (4JG2 only)

Quick-On Start System Inspection Procedure