Intermittent, crank, start, die after 2 seconds

[Steve3P0 Lurker Find all posts View Profile Close Steve3P0]

Hey everyone.

Gonna try be as informative as possible.
My car is a 2000 1kz-te diesel

The problem.
Sometimes when I try to start, the car will crank, start up, rev normally, then die. Even if I am sitting on the accelerator it will just lose revs and die.
This has been happening for over a year now but happens infrequently enough for me to ignore it.
If the car starts for more then 3 seconds it has absolutely no issues while running.

How I get it to start
Honestly not much. I will normally prime it once it no longer starts after cranking(usually after 2 or so attempts) and just repeat this until it starts. Sometimes it will start first go. Sometimes it will start after 2 hours of this.

Current hypothesis
After looking around here, talking to a few people, and driving a grand cherokee which would behave in the same way if you forgot to unlock the car with the fob button, I am thinking it is something to do with the immobiliser system.
The immobiliser light turns off when I insert the key.
Due to the inconsistent nature of the problem it makes me think about faulty wiring.
Does the immobiliser work by disableing the fuel pump? That could explain why I have to prime it.
It could be a fault with any system that has control over the fuel pump on startup.

What I have tried
Not to much really. I've replaced the fuel filter, checked for leaks in the line.
Resently I have switched to using my spare key to test if it is from a damaged chip in the key. (hasn't failed to start since the switch but I am not reading to much into it, as sometimes it will be fine for months on end before playing up again)

What I want help with
I would love to know about any system that has control over the fuel pump on startup.
How the Immobiliser is wired and how to test its connections.
Any other theories as to why the car wouldn't start.

The reason I'm working on it now is because I'm currently under employed so solution that I can test myself would be ideal. I do have access to a fairly good workshop.

Thanks in advance for your help, Steve
PS don't hesitate to suggest solutions not related to the immobiliser. That is just my current theory but this really has had me stumped for a long time.

[scottkz Senior Member Find all posts View Profile Close scottkz]

The key fob( central locking) has nothing to do with the imobilizer,
The flashing key light on the dash should got out once the key is inserted
The key has a chip which once inserted not near but inserted as it has a switch in the barrel transmits to the barrel surround then to the imobilizer ecu the to the engine ecu . Im not sure what it cuts... fuel cut soloniod or ecu power maybe
Trya a different key?
There is a test procedure you can do on them i can look in my manual

[Steve3P0 Lurker Find all posts View Profile Close Steve3P0]

Hey thanks for the reply.
I was aware that the fob has nothing to do with prados immobiliser I was talking about the grand cherokee I was driving the other week as an example of a car with a similar problem.

I have been using my spare key for the last few days. Unfortunately it failed to start again yesterday so that rules out the chip in the key (unless they are both faulty). Wasn't aware of the test procedure, I'll take a look when I get back to the car.

The flashing immobiliser light turns off everything I insert they key (even when it goes on to fail).

Yesterday when I was filling up at a servo it failed to start after I paid meaning it can fail even when warm.