2nd Apr 2015, 13:45

What could be the problem with my Isuzu Wizard failing to start?

13th May 2015, 21:32

Mine is cutting out when I change from reverse to drive, and then the check trans light comes on.

30th Jul 2015, 10:02

I have Isuzu Wizard 3.0 4JX1 turbo diesel from 1998, which is not responding very well. Sometimes it just cuts itself. Sometimes the accelerator won't respond even when I'm driving. When I took it to the agency to see, they told me that the problem is with the oil pressure sensor. Please, where can I buy an OIL PRESSURE SENSOR with this reference: 3CP16-1 / TI7278C?

Email me on: sergiotaibo@Yahoo.com.br

Thank you!

28th Jun 2016, 03:35

Mark Cromie Motors Whangarei. Very good parts & they have good knowledge of the Wizard. Mine was the oil sensor causing a hard start & cutting out while driving!

7th Jul 2016, 20:12

Hello there,

I have Isuzu Wizard 3.0 4JX1 turbo diesel from 1998, which is not responding very well. Sometimes it just cuts itself. Sometimes the accelerator won't respond even when I'm driving. But shortly after you can start it well again, but it will repeat this.

Your help will really be appreciated. Please email me on akkintu@gmail.com or on whatsapp +256792111000.

Thanks so much.

3rd Aug 2016, 23:42

Hi there, I have the Bighorn 30td 1999 on a T plate. Had a problem with the starter motor clicking; it would start one time out of ten turns, so got another one, went to change it, but forgot to take the live off the battery and got a spark off the starter motor. Anyway, done it how it should have been done, changed it over, put everything back, turns over as it should, but now won't start at all. Can anybody help please?

20th Sep 2016, 10:14

Got an Isuzu Wizard diesel 4jx1. After the replacement of the o-rings it started to smoke - white smoke. Previously was getting diesel in the radiator. Please help.

27th Oct 2016, 10:06

I have a similar problem. Have discovered oil coming out of the delivery from the pump to the injectors. Is this the o-rings on the injectors?

27th Jun 2017, 13:15

Hi, has the problem of mixing diesel and coolant, and draining coolant to the fuel tank been solved?

I have the same problem; I don't know how it can be solved.

3rd Jul 2017, 00:15

Hi, the same thing happening to me; did you manage to find out the problem?

6th Aug 2017, 06:58

Hi, I have a 2000 Isuzu Wizard 4jx1. When I first bought it, it had 2 injector failures so I had them replaced and it ran smoothly for a few days until I started hearing an unusual sound from the engine. Turned out to be a broken valve.

I had that fixed as well, now the car runs somewhat smoothly, but during long distances it loses power after some 200km and starts emitting a cloud of black smoke as I try to accelerate; what could be the cause of this?

And how many times does coolant needs to be topped up? The need seems to be arising once or twice every week.

13th Oct 2017, 08:10

Most problems with the CAT HEUI 4JX1 are due to just a few things.

Oil must be 5w30 or 40 replaced every 5k with a large filter and a small one every 10k.

Use ISUZU filters, especially for the high pressure circuit (small one).

When engine oil rises, it is either the internal injector seals (injectors only good for 80 to 100k) or the upper injector to sleeve O-ring gone. When diesel is mixed with coolant, the sleeve to head O-rings have gone, coolant will also be returning with fuel to the fuel tank.

The injector to sleeve and sleeve to head O-rings should be replaced every 50 to 80k. Valve clearances should be done every 80k, so while the injectors and rail are off to do these, it's a simple job to do the sleeve seals.

If it is hard to start cold, or doesn't start at all, it will likely be one of three things (excluding glow plugs):

The Oil Rail Pressure Sensor (ORPS). This can be tested by disconnecting the 'white' signal wire of the injector harness, between the sensor and ECU; if she fires up within a few seconds when cold and having sat idle overnight, the sensor is playing up.

Or it could be the Oil Rail Pressure Control Valve (ORPCV); this can get clogged with carbon, metal filings, bits of gasket etc and not allow sufficient pressure in the rail to allow the ECU to fire the injectors.

Alternatively there are two oil pickups in the oil pan; the seals on these deteriorate with age and allow air to be sucked in bypassing the oil, especially when the oil is cold and thick. The pipes of these pickups are prone to cracking if you do a lot of offroading.

Another sensor that wears and causes strange behaviors is the Throttle Position Sensor (TPS) They should be replaced every 50k if not before as preventative maintenance.

Once you get these things sorted, and keep an eye on your fluids, the 4JX1 is a reliable grunty workhorse you can rely on.

I learnt most of the above from this site.


I've done my own sleeves and have full confidence in our old truck now, even to continue venturing deep off road on mountain tracks. We just love our old girl to bits.

9th Sep 2018, 10:26

I have the same problem; can you help me?