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Recent Posts

Fuel leak front of engine

Hello my Jackaroo is leaking a lot of diesel under the engine and when I get underneath it I am having trouble locating exactly where it is coming from.It does not go as far up as the priming pump but is after the section in the fuel line in the front end of the body.Is […]

Funny oil pressure woes

J5, the Blue Jack has been noisy of late, with #4 manifold gasket blown and lots of noise.

But before that, J5 had been stalling as I went around corners. Not every time, but quite often and the last time, I could not get it to start and the dash oil light remained on.

ORPS, […]

Gearbox sensors

Recently with J5, I had to clean underneath and remove the accumulated oil etc. Not a nice job, but went to the manual to check what all the plugs (full of oil) actually did:

Injectors fail to fire

This is a hard one to be sure about, without resorting to a TECH-2.

However, it must be remembered that for a “start” to occur, there are a series of pre-existing conditions:

There is fuel to the front of the oil-rail; There is oil at full pressure to the oil-rail; The oil does not smell […]

Complex problem

In April 2016, I had a well running machine, with a very good fuel consumption – 11.0l/100km with a 850kg trailer in tow and no issues, except for a come and go problem of an engine warning which said that the ECU was “cactus”.

I had replaced #1 injector twice in the previous 4000km, as […]


Fuel supply for 4JX1 motor:


Is fuel through to banjo at the front of head? [17mm ring spanner and loosen, don’t remove]; Is there fuel at filter head?? [10-mm spanner loosen before pushing bleed knob, then tighten before releasing to ensure fuel not dropped back to the tank]; If fuel there, engine […]

Fuel supply problems

I believe that the fuel uptake is a real unknown problem for the 4JX1 motors. As we know, fuel supply is critical to the cooling of the head, with fuel being by-passed to the rear of the head, then into the fuel tank.

There is a fuel temperature sender at the rear and those with […]

Jackaroo 4JX1

A great machine, but needs careful care. There have been some horror stories out in Jackaroo land, with people left stranded with large bills, which trace back to poor understanding of what is, a complex machine.

The engine, which is a common rail with a HUEI system [see below]


Suggested Actions for […]

4JX1 Engine and some useful references

The following are useful references for the Jackaroo [4JX1 – Diesel UBS-73]

1. Alternate to the OBD-II

Quality source of tuning materials, which relpace the TECH-II instrument and can be read on a lap-top through the Jackaroo’s UBD-II port.

You need a Universal OBD-II Scan Tool w/Bluetooth Wireless Interface to use immediately. This one […]

Welcome to 2016, the New year and the Jackaroo 4JX1

Welcome to the Blog site for the Jackaroo – 4JX1 4WD


UBS-13 and UBS-73