Isuzu Wizard - Starting Issues

02-01-2005, 08:39 PM
I have a 1998/99 Isuzu Wizard with a 4JX1 Engine (3.2l Diesel) which has done 38,000kms (I have only had it for 6 months - we have done about 3,000kms).

About 2 weeks ago my wife was unable to start it and it was taken to a specialist in Turbo's and Diesels. Unfortunately at this moment in time they have been unable to fix the problem (it has been scanned by 3 companies gear, all of whom are the respective agents for Isuzu/Holden). That is why I have turned to this forum (for help please)!

They state the 4JX1 Engine is too advanced for their scanning tools and unless it has a fault light, then nothing will appear on the scanner.
Talking to them, they really don't have any ideas as to what is wrong...and they don't know of anyone else locally to send it to. They are at the point where they are going to just try things until it miraculously works. That may be the only option I have left, but I would prefer that it had some logical direction (as each experiment costs me and takes time).

I am hoping someone out there may have seen this fault before (especially from another country) and can give me somewhere to go with this (basically I have no avenues left to try)...other then their try it and see approach.

The symptoms of the problem are:

1. It started as an intermittent problem (only about 4 weeks ago) when we start the vehicle (Note: We had an alarm installed the day before this problem appeared, I felt it was something to do with this but even after removing the alarm it is still not going)?

The original problem was, it would start as normal but when I went to take off, the engine would lag, struggle and the car would crawl along (it had no power) but it continued to run, it didn't cut out. I would stop (engine still going), put it out of gear and rev, it would be fine, then take off again and it would struggle as before. I tried turning off the AC, Radio and all electrical devices in the car, it seemed to work (could be a coincidence) and then off it would go as if nothing happend.

Note: There wasn't any black or white smoke shooting out of the rear when power just went as normal

2. The day before we sent it in to the specialists, these symptoms appeared. I had just returned from a trip (2+ hours of driving) and decided to just pop to the local store. The car had been sitting for about 45 minutes. I got in and tried to start the car. The car would start and stop almost immediately after it reved (it was a gradual stop - sort of a splutter then stop). I tried restarting it and it did this a couple more times. I then tried it in Neutral, turned off all electrics and it eventually started. There was a smell of diesel but no smoke. I drove to the store, but when I tried starting it again, it did the same thing. When it eventually started, I drove home but it was running very sluggishly (possibly rough) and when I stopped, it choked to a halt. I didn't use it the rest of the day but told the wife to keep an eye out for it the next day.

3. The next day my wife tried to use it and it wouldn't start at all. Nothing she tried worked. We called a mobile technician, he came and guess what, it started. However, after a repeat of stoping and starting it eventually didn't go at all. Since then it has been in the workshop, moved from specialist to specialist and it still isn't going.

- The Alarm people came back and removed the alarm (it is no longer installed) - but it still doesn't start
- They have changed the oil (said it didn't have the right oil in it) didn't have any affect on this problem
- They changed the fuel flow valves to one way units (something to do with build up of fuel pressure), no affect on this problem

One of the specialists wants to send the EFI Valves away overseas for testing (is that a good idea - seems expensive and a reach in the dark to me)?

I have checked this forum and others for this problem. Unfortunately nothing is 100% the same but I have a short list of the problems closest to this issue (although the experts suggest that some are specific to older models, which have been fixed in the 4JX1 engine).

- Idle control Valve?
- Bad Fuel Pressure Regulator?
- Fuel Injector Oil Leak into Fuel/vice versa?
- Loose wire in fuel pump connection?
- Oil Gasget Leak or Blockage?
- Computer Issue?

Note: When starting this vehicle it seems to take longer then previous Isuzu's we have had (it takes about 4 to 6 seconds before firing up) but it always did start up before this happend...could the starter be faulty?

I had a similar issue with my Subaru Legacy which was fixed by replacing a sensor - don't know which one (something to do with the vehicle starting, not knowing it was running or thinking it was when it wasn't and would stop or wouldn't start)...could this be the problem and if yes, what/how would we know?

If anyone out there has any ideas, it would be appreciated.
Cheers in advance...

02-01-2005, 10:02 PM

try posting your question to the above isuzu deisel forum

4JX1 Jack
09-16-2005, 01:05 AM
When it comes to the Oil, you will need to change it up to 3 times before all of the old crud is out of the system. This is because not all of the oil is drained when the sump is emptied, some is still retained in the HEUI injection circuit.
I have come across this on another forum and I quote some advice from there:
Could be the pressure sensor, one way to check this is this... in the plug by the dipstick tube there is a lot of pink wires but one right in the middle is usually white remove this from the plug this gives the ecu a base reading of 27.9 mpa thus bypassing the pressure. now try to start it if it fires (it may run rough because they don't get that high usually and it's only a test to see if it starts when it hasn't before) then it's the sensor if not then it's either got no fuel or no oil.
to determine what one it is crack the little bleed screw off on the filter housing and bleed the system do the bolt up then give it a few pumps until the primer goes hard then try to start it. if it starts it's a fuel problem and over here in the uk we can fit a one way valve to stop the fuel draining back to the tank.
if it still doesn't start crack the big nut off on the gold pipe that goes in to the rocker cover and crank the engine oil should come out of here at a fair old rate of knots if it just dribbles out then the oil rail pressure control valve is stuck open and will require replacing.
hope this helps

10-03-2005, 03:12 AM
Hey what country are you in? Australia?
This may seem obvious, but it happened to me once:
How tight are the battery terminals? Is there a short
somewhere due to sloppy alarm installation?
A loose Neg. Batt terminal drove me nuts for a few days
on an old Dodge Caravan.
Good Luck!
-in California

04-18-2006, 05:52 AM
Hey hope you got your car going,

If you haven't, try sealing the 'o' rings on the oil pick-ups, the one on the LHS is the one that supplies oil for the injectors. Because the injectors are controlled by oil pressure any air passing this 'o'ring can cause starting and running rough faults.

04-22-2006, 12:43 AM
Hey help me out if you can....

I have a 2001 rodeo ls that is reading a randome multiple cilender misfire...
what else could be wrong other than a bad ignition mod..

open for discussion


11-14-2009, 08:21 PM
get your truck's diesel pump and automizers checked. I had exactly the same problem with my diesel engine. As soon as the car warmed up it stalled on me like it had it's fuel supply cut off. I let it sit for a while and it would run fine for some time then did the same thing again. I had the automizers replaced and the the plunger inside the diesel pump was replaced. My car is running like new again. hope this helps solve your problem.

06-01-2010, 11:44 PM
Dear Friend,

i am writning from mongolia, i had the same problem my isuzu wizard with 4jx1 engine,

how did you solve your problem?

please give me suggestions, my email is

best regards,

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