96 NJ Cranks, no Start

[daz33]

Hi, have a 96 NJ 3.5 that cranks fine but doesn't start. Has fuel and spark. Ol Mate that I bought it from seems to be under the impression that it's emobiliser related? It was driving fine then stopped, he let it sit for a bit and it started again then he turned it off then it wouldn't start again, just crank.

Does the key play any part in this?
Or could it be a range of other things?

Any ideas appreciated.

Cheers, Daz.

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[Keithyv]

If you have fuel and spark then it should run!
Immobiliser would usually mean there is no spark I would think..

[daz33]

If you have fuel and spark then it should run!

Immobiliser would usually mean there is no spark I would think..

Apparently, this is not fact, but it stops the pulse to the injectors!?

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[nj swb]

I'm with Keithyv - if it has fuel & spark it should run.

If the immobiliser is stopping it from running, how? If it's not stopping spark, or it's not stopping fuel, then what is it stopping?

How does the OP know it has fuel? Is each injector literally spraying fuel properly into each cylinder while cranking?

How does the OP know it has spark? Pull each lead, stick a spare plug into it, carefully ground the plug and then watch it spark while cranking?

If injectors are spraying properly and plugs are firing, it should run. Unless some timing signal is way outta whack, and injectors and plugs are all happening at the wrong time? How does that "just happen" i.e. without things being pulled apart and incorrectly reassembled?

The "just stopped" then "some time later started again" sounds like a crank angle sensor. But, as I understand it, if the crank angle sensor has failed then injectors and plugs don't fire - no fuel, no spark.

[daz33]

I'm with Keithyv - if it has fuel & spark it should run.



If the immobiliser is stopping it from running, how? If it's not stopping spark, or it's not stopping fuel, then what is it stopping?



How does the OP know it has fuel? Is each injector literally spraying fuel properly into each cylinder while cranking?



How does the OP know it has spark? Pull each lead, stick a spare plug into it, carefully ground the plug and then watch it spark while cranking?



If injectors are spraying properly and plugs are firing, it should run. Unless some timing signal is way outta whack, and injectors and plugs are all happening at the wrong time? How does that "just happen" i.e. without things being pulled apart and incorrectly reassembled?



The "just stopped" then "some time later started again" sounds like a crank angle sensor. But, as I understand it, if the crank angle sensor has failed then injectors and plugs don't fire - no fuel, no spark.

Your post sounds logical, so maybe it's not the emobiliser, i don't know who told him this or how he came to that conclusion. I'm told the spark and fuel was checked and was present.

Maybe i just get an auto elec or mechanic to look at it. Sounds like it's a bit more complex than what was first thought.

Cheers.

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[stumagoo]

immobiliser stops the injector pulse ... try removing the intake from teh throttle body and use some easyt start - spray into the tb while turnning over and if it fires its fuel - then check for fuel at the return line ( the smaller of the fuel lines) the fuel pump should run when the ignition is at the start position and run for 2-3 seconds after as well... if you have fuel and easy start allows it to fire then yes most likely its the immobiliser.

[daz33]

immobiliser stops the injector pulse ... try removing the intake from teh throttle body and use some easyt start - spray into the tb while turnning over and if it fires its fuel - then check for fuel at the return line ( the smaller of the fuel lines) the fuel pump should run when the ignition is at the start position and run for 2-3 seconds after as well... if you have fuel and easy start allows it to fire then yes most likely its the immobiliser.

Ok, so it is a thing.... i will check tomorrow.

Cheers.

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[stumagoo]

Not all NJ models have immobilisers. if you do you will have a molded plastic head on the key. if you have a plain metal key that used to work then no factory immobiliser. if there is a factory immobiliser then try a second key. also if you turn the ignition to on and put the ecu into diagnostic mode then it will flash code 54 if the immobiliser is activating.

[daz33]

Not all NJ models have immobilisers. if you do you will have a molded plastic head on the key. if you have a plain metal key that used to work then no factory immobiliser. if there is a factory immobiliser then try a second key. also if you turn the ignition to on and put the ecu into diagnostic mode then it will flash code 54 if the immobiliser is activating.

Here's the only key i got with it.

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[erad]

As above - IF you are sure that you have spark, try to smell the exhaust and see if you can smell petrol. If you can, then you have fuel and can rule out the immobiliser because that cuts out the fuel (not the spark). You should not be able to smell the petrol really rich though - if you can it probably means that you have too much fuel going into the cylinders.

If you are sure that you have fuel AND spark (the fuel being at the correct mixture), then the only thing left is WHEN the spark occurs, ie the crank angle sensor. Try to get hold of an old fashioned timing light (preferably one with an inductive pickup). Then check the spark. If it is in a constant place on the crankshaft pulley, then you can rule this out. I had my CAS fail, and the timing was bouncing all over the place until eventually the beast would not fire at all.

[geopaj]

Have you read the diagnostic codes? As suggested above I would also be checking spark and that the injectors are spraying fuel.

[daz33]

A mate is coming over at some stage, depending on restrictions who is going to take a look. I think he has a scan tool, I'm assuming the MUTT type. I might look up how to do it earthing pin 1 maybe rather than wait.

But I'll do all the other checks as well.

Cheers, Daz.

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[stumagoo]

Here's the only key i got with it.

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that key is the style that can have an rf chip in it. so there is a chance it has an immobiliser- I have seen it in NJ models before but its not common here in Aussie

[daz33]

So i threw some 'start ya bastard' into the plenum and turned her over and nothing still. Given this I'll assume it's not fuel but spark. I was told it had both when i bought it but didn't confirm that myself.

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[geopaj]

Have you read the diagnostic codes? As suggested above I would also be checking spark and that the injectors are spraying fuel.

A mate is coming over at some stage, depending on restrictions who is going to take a look. I think he has a scan tool, I'm assuming the MUTT type. I might look up how to do it earthing pin 1 maybe rather than wait.

But I'll do all the other checks as well.

Cheers, Daz.

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This explains how to read the codes.

https://www2.pajeroclub.com.au/forum/showthread.php?t=33491

I would disconnect the batter for a couple of minutes (to delete any historical codes), attempt to start it once the battery is reconnected, and then see if you can extract any codes.

Can you please also post the outcome?