This manual is provided by SHENZHEN TAI TRADE LTD.
The ISUZU 4JB1 is a 4-cylinder, naturally aspirated, water-cooled, in-line direct injection engine equipped with a VE rotary injection pump, featuring high-revving and high-output capabilities. The industrial version has a horsepower of 90 ps, and the torque reaches 135 lb.-ft. at 2000 rpm. The light version of the 4JB1 adopts a gear-type oil pump and Bosch "A" type mechanical injection. It has a dry weight of 230 kg (510 lb). Before the early 1990s, this engine was widely used in vehicles such as the Isuzu Bighorn (Trooper), Mu (Rodeo), Wizard (LWB Rodeo), Rodeo Pickup, and Holden Jackaroo sold in most markets around the world except North America. It was also installed in the Isuzu Elf 150 and other light trucks.
Oil Check
Regularly check the oil level. It is recommended to do this after the engine has cooled down. Park the vehicle on a flat surface and pull out the dipstick. The oil level should be within the normal range marked on the dipstick.
Replace the engine oil according to the cycle specified in the vehicle user manual. Generally, it is every 5000 - 10000 km. Use oil that meets the specifications, such as diesel engine oil of API CD grade or higher.
Coolant Check
Check the coolant level to make sure it is between the "MIN" and "MAX" marks on the expansion tank. If the level is too low, add coolant in time. Note that you should use the same type of coolant mixture as the original to prevent chemical reactions.
Replace the coolant every two years or about 40,000 km to ensure the good performance of the cooling system.
Air Filter Cleaning and Replacement
Regularly take out the air filter element and gently tap it or use compressed air to blow from the inside to the outside of the filter element to remove dust and impurities.
Replace the air filter element every 20,000 - 30,000 km to avoid power reduction and increased fuel consumption caused by poor air intake.
Fuel System Maintenance
For engines equipped with a VE rotary injection pump, regularly check the tightness of the injection pump to see if there are any signs of fuel leakage.
Clean the fuel injectors every about 30,000 km to ensure good fuel atomization. Professional fuel injector cleaners or ultrasonic cleaning equipment can be used.
For the Bosch "A" type mechanical injection device used in the light version, also pay attention to the adjustment of its injection pressure and calibrate it according to the specified cycle, generally every 20,000 km.
Lubrication System Maintenance
Besides oil replacement, check the oil filter every 10,000 km. If it is found to be clogged or damaged, replace it in time to ensure the cleanliness of the engine oil.
Check the lubrication points of various parts of the engine, such as the crankshaft oil seal and camshaft oil seal. If there is oil leakage, replace the oil seal in time.
Timing System Inspection
Check the tension of the timing belt or timing chain every 40,000 - 50,000 km. If it is too loose or too tight, it will affect the timing accuracy of the engine, leading to performance degradation or even engine damage. The timing belt is generally replaced every 80,000 - 100,000 km, and the timing chain is replaced when necessary according to the Wear condition.
Difficult to Start
Causes: It may be due to insufficient battery power, clogged fuel filter, faulty fuel injector, or starter failure, etc.
Troubleshooting: First, check the battery voltage with a multimeter. If the voltage is lower than 12V, charge or replace the battery. If the battery is normal, check the fuel filter and clean or replace the clogged filter element. If the problem persists, check the fuel injection condition of the fuel injector and clean or replace it if necessary. Finally, if the starter rotates weakly, repair or replace the starter.
Engine Vibration
Causes: Poor spark plug ignition, abnormal operation of individual cylinders, uneven fuel supply, etc.
Troubleshooting: Check the spark plugs. If there is carbon deposition or erosion, replace them in time. Use a cylinder pressure gauge to measure the pressure of each cylinder. If the pressure difference is large, it may be due to worn piston rings, poor valve sealing, etc., and further disassembly and repair are required. Check the pulse and injector to ensure even fuel supply and repair or replace the faulty parts.
Lack of Power
Causes: Clogged air filter, turbocharger system failure (if equipped), fuel injection system failure, etc.
Troubleshooting: Clean or replace the air filter element. If it is a turbocharged engine, check the impeller, bearing and other components of the turbocharger to see if there are any damages or looseness and replace them if necessary. Conduct a comprehensive inspection of the fuel injection system, including the injection pump and injector, adjust the injection pressure, and clean or replace the faulty parts.
Before disassembling engine components, be sure to disconnect the negative terminal of the battery to prevent short circuits and damage to electronic components.
During the maintenance process, use appropriate tools and tighten bolts and nuts strictly according to the torque values specified in the maintenance manual to avoid component damage or poor sealing caused by improper tightening force.
For precision components, such as injection pump and injector, the maintenance operations should be carried out in a clean environment to prevent impurities from entering and affecting performance.
When replacing parts, be sure to select original factory parts or reliable aftermarket parts to ensure the reliability and stability of the engine.
Maintenance personnel should strictly follow the requirements of this manual when maintaining and repairing the ISUZU 4JB1 engine to ensure that the engine is always in good operating condition.
This manual is provided by SHENZHEN TAI TRADE LTD.
The ISUZU 4JB1 is a 4-cylinder, naturally aspirated, water-cooled, in-line direct injection engine equipped with a VE rotary injection pump, featuring high-revving and high-output capabilities. The industrial version has a horsepower of 90 ps, and the torque reaches 135 lb.-ft. at 2000 rpm. The light version of the 4JB1 adopts a gear-type oil pump and Bosch "A" type mechanical injection. It has a dry weight of 230 kg (510 lb). Before the early 1990s, this engine was widely used in vehicles such as the Isuzu Bighorn (Trooper), Mu (Rodeo), Wizard (LWB Rodeo), Rodeo Pickup, and Holden Jackaroo sold in most markets around the world except North America. It was also installed in the Isuzu Elf 150 and other light trucks.
Oil Check
Regularly check the oil level. It is recommended to do this after the engine has cooled down. Park the vehicle on a flat surface and pull out the dipstick. The oil level should be within the normal range marked on the dipstick.
Replace the engine oil according to the cycle specified in the vehicle user manual. Generally, it is every 5000 - 10000 km. Use oil that meets the specifications, such as diesel engine oil of API CD grade or higher.
Coolant Check
Check the coolant level to make sure it is between the "MIN" and "MAX" marks on the expansion tank. If the level is too low, add coolant in time. Note that you should use the same type of coolant mixture as the original to prevent chemical reactions.
Replace the coolant every two years or about 40,000 km to ensure the good performance of the cooling system.
Air Filter Cleaning and Replacement
Regularly take out the air filter element and gently tap it or use compressed air to blow from the inside to the outside of the filter element to remove dust and impurities.
Replace the air filter element every 20,000 - 30,000 km to avoid power reduction and increased fuel consumption caused by poor air intake.
Fuel System Maintenance
For engines equipped with a VE rotary injection pump, regularly check the tightness of the injection pump to see if there are any signs of fuel leakage.
Clean the fuel injectors every about 30,000 km to ensure good fuel atomization. Professional fuel injector cleaners or ultrasonic cleaning equipment can be used.
For the Bosch "A" type mechanical injection device used in the light version, also pay attention to the adjustment of its injection pressure and calibrate it according to the specified cycle, generally every 20,000 km.
Lubrication System Maintenance
Besides oil replacement, check the oil filter every 10,000 km. If it is found to be clogged or damaged, replace it in time to ensure the cleanliness of the engine oil.
Check the lubrication points of various parts of the engine, such as the crankshaft oil seal and camshaft oil seal. If there is oil leakage, replace the oil seal in time.
Timing System Inspection
Check the tension of the timing belt or timing chain every 40,000 - 50,000 km. If it is too loose or too tight, it will affect the timing accuracy of the engine, leading to performance degradation or even engine damage. The timing belt is generally replaced every 80,000 - 100,000 km, and the timing chain is replaced when necessary according to the Wear condition.
Difficult to Start
Causes: It may be due to insufficient battery power, clogged fuel filter, faulty fuel injector, or starter failure, etc.
Troubleshooting: First, check the battery voltage with a multimeter. If the voltage is lower than 12V, charge or replace the battery. If the battery is normal, check the fuel filter and clean or replace the clogged filter element. If the problem persists, check the fuel injection condition of the fuel injector and clean or replace it if necessary. Finally, if the starter rotates weakly, repair or replace the starter.
Engine Vibration
Causes: Poor spark plug ignition, abnormal operation of individual cylinders, uneven fuel supply, etc.
Troubleshooting: Check the spark plugs. If there is carbon deposition or erosion, replace them in time. Use a cylinder pressure gauge to measure the pressure of each cylinder. If the pressure difference is large, it may be due to worn piston rings, poor valve sealing, etc., and further disassembly and repair are required. Check the pulse and injector to ensure even fuel supply and repair or replace the faulty parts.
Lack of Power
Causes: Clogged air filter, turbocharger system failure (if equipped), fuel injection system failure, etc.
Troubleshooting: Clean or replace the air filter element. If it is a turbocharged engine, check the impeller, bearing and other components of the turbocharger to see if there are any damages or looseness and replace them if necessary. Conduct a comprehensive inspection of the fuel injection system, including the injection pump and injector, adjust the injection pressure, and clean or replace the faulty parts.
Before disassembling engine components, be sure to disconnect the negative terminal of the battery to prevent short circuits and damage to electronic components.
During the maintenance process, use appropriate tools and tighten bolts and nuts strictly according to the torque values specified in the maintenance manual to avoid component damage or poor sealing caused by improper tightening force.
For precision components, such as injection pump and injector, the maintenance operations should be carried out in a clean environment to prevent impurities from entering and affecting performance.
When replacing parts, be sure to select original factory parts or reliable aftermarket parts to ensure the reliability and stability of the engine.
Maintenance personnel should strictly follow the requirements of this manual when maintaining and repairing the ISUZU 4JB1 engine to ensure that the engine is always in good operating condition.
