4JX1 diesel engine

4WD Truck – Izusu Trooper/ Jackaroo

Identification of Engine:
VIN-Code [a stamped-plate on the bulkhead below the windscreen]. The whole VIN is JACUBS73G17xxxxxx
Where ‘UBS’ means a 4×4 with SUV-type body and ‘G’ means Long Wheel Base, 4-Door Engine Codes 69 = 4JG2 73 = 4JX1 17 = 4ZE1 [2.5L Gas] 58 = V6 [4L Gas] 26 = 6VE1 [3.5L Gas]
UBS69 = 3.1 turbo diesel motor (4JG2) Trooper/Bighorn/Jackaroo
UBS73= 3 turbo diesel motor (4JX1) Trooper/Bighorn/Jackaroo [4JB1-T engine will replace 4JX1]

  1. Overall operation of the 4JX1 Engine:

Suggested Actions for Owners [Injector Article written by Red-one]
Ensure the correct type and grade of oil is being used in the engine. Correct operation of every part of the injector oil circuit is critical to the successful operation of this engine. The piston within the injector has to move exactly the correct distance to deliver the correct quantity of fuel, and operate at exactly the right moment in the engine cycle, for the engine to run correctly. Selection of a good quality oil, of suitable viscosity, clearly plays a vital part in this.
Check sump oil level regularly (at least once per week), and be aware that a rising oil level could be the start of other problems.
Keep a wary eye open for fluid loss or leaks such as oil leaks from engine seals, or the smell of diesel in the coolant.
Holden Jackaroo owners – contact Holden and enquire whether the Campaign 03-H-03 has been done on your vehicle. Note this Campaign relates to the injector sleeve sealing O-rings, which according Holden : “can deteriorate and cause fuel to leak into the crankcase”. If not, book it in – Holden should do this free of charge.
At each 80 k kms service interval, replace the O-rings between injectors and sleeves, and between sleeves and cylinder head, as a precaution. This will add little to the overall cost of the service, as the mechanic will already be working in this part of the engine, checking and adjusting the valve clearances.
If the oil level in the sump rises to the point that it enters the crankcase breather pipe, the engine may start to run on it’s own oil. In this situation, in Holdens words : “ this may result in an unintentional increase in engine speed, and possibly vehicle speed”.
If this happened, it would cause most people to get very alarmed, especially if it happened in heavy traffic, driving at high speed, etc.. The engine will no longer respond to normal throttle operation, and will continue to run even with the ignition switched off.
In extreme cases, engines have been known to red-line and self destruct. In the UK, there have been cases of engines being replaced free of charge by Isuzu.
If a motorist is unfortunate enough to experience a run away engine, the best advice is to immediately steer in a safe direction, engage the highest possible gear and jump on the footbrake and hand brake together to stall the engine. Only depress the clutch or engage neutral as a last resort as this will allow the engine to spin freely out of control.
This will be alien to most normal driving, and against normal instincts. Failure to stop the engine at this point may lead to a very expensive engine rebuild. Staying on a high traction surface eg bitumen would be better than driving onto loose sand – spinning wheels would have little braking effect on the engine. Do not turn off the ignition before the vehicle comes to rest, to avoid locking the steering wheel.

What is a Diesel engine and questions on operations??

A diesel alters engine speed by varying the amount of fuel to the injectors.
Disagree. By the amount of fuel and AIR. And air is as important as fuel
A diesel does not need a throttle plate. In fact all it would do is restrict airflow and reduce efficiency.
Disagree. Amount of air coming to intake manifold and staying there prepared to be pushed in the cylinders is calculated and controlled by MAP sensor and Throttle body sensor.
If we can replace this to by airflow metering sensor like at petrol cars – yes, we can eliminate the throttle (possibly) but at our conditions – we cannot.
The size of the pipe x pressure inside = amount of flow through
Normally fuel injector output by the ECM controls air/fuel ratios (the Lambda ratio).
This is by using the data from ALL sensors: Fuel temp, intake air temp, coolant temp, MAP, TPS
Can you feed the EGR system with clean filtered air instead of dirty combusted air – This part is easy, but how you will heat it to the same temperature?
That’s a question.
Another is a pressure of this pre-heated air and third is an oxygen concentration as well. Recycled air is used to reduce the burning temp in the cylinders by this I assume that oxygen concentration should be lower.
But it seems that Isuzu fitted a throttle plate mainly for the EGR, which means that throttle plate openings are timed to suit the EGR manifold vacuum requirement, so the system is well embedded in the ECM’s programming.
EGR system is secondary.
It uses some data from Temp sensors, Pedal sensor, TPS and Map, and operates controlled by software algorithm, limited by EGR pressure sensor as well.
About the picture of intake pipe and pressure.
A thought that a square box marked at the picture is a silencer.
The surface of air filter is many times higher that a surface of this small hole joining the silencer to the intake pipe. Incomparably smaller, so no dumping of vacuum.
Crankcase vapours goes out with a bit of pressure that’s the gas coming through the piston rings and accumulating inside the engine.
That’s why all you need – guide them into the catch can where they change direction of flow and leave oil particles at the walls of the can.
Please be careful with putting some membrane (or mesh) filters or anything else inside, because if you completely block the ventilation these gases could find another way to go by pressing out some seals. Just imagine that this could be a crankshaft seal at the back (near gearbox) and get the price of fixing these tuning results.
WBR Sergey