300tdi cuts out,help pls

Hi all never posted on this or anywhere else so please bare with me .
I finally saved up me pennies and bought a 1996 90 300tdi, and all was well for a while .Then
one day heading down the road she cut out ! she would turn over but no start , I sat a while and sctached , then she turned over and started ,off i trundled. This became a bit of a regular occurance when the engine was hot , never when cold, so after homework a taking advice from those that know better, i changed fuel filter( and all other filters ), changed lift pump , dropped and cleaned fuel tank ( no dirt in there ), changed glow plugs ,changed solenoid on pump , and finaly had fuel pump tested/serviced ( turns out the pump had a hairline crack in casing so i thought finally got to the bottom of the issue !) but NO , its still happening ! I am now at a good few quid lighter , frustrated, ****ed off , and hence posting here , any suggestions as to the problem ? D

Sounds like you have gone through the usual suspects.
As an experiment run a line direct from battery to the fuel pump solenoid with a on/off switch somewhere handy in it and then run like that for a while to see if you keep going.

tottot said:

Sounds like you have gone through the usual suspects.
As an experiment run a line direct from battery to the fuel pump solenoid with a on/off switch somewhere handy in it and then run like that for a while to see if you keep going.

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Hi thanks for getting back , pls understand I am feckin next to useless at engines , a work in progress you could say . Can you tell me what this will demonstrate? I am guessing if it doesn’t cut out then I have a faulty electric connection between solenoid and glow plug relay ?

Or the relay is heating up and cutting of the fuel ? Then cooling down and allowing the fuel to flow again ?

I am thinking more of a fault from ignition to fuel pump solenoid. If it goes through a relay could be that or it could be fail in the ignition switch itself or a failing in the wiring.

Pretty much the only thing that will not allow a 300tdi engine to start (in the way you are describing) is the fuel cut off solenoid not getting any power.
I agree with @tottot

A wire through a switch (that's important or the engine won't stop) from a power source directly to the solenoid. it bypasses the wiring in your D90, if it works, then you need to find the faulty cable/connector..

miktdish said:

Pretty much the only thing that will not allow a 300tdi engine to start (in the way you are describing) is the fuel cut off solenoid.

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To be pedantic ( sorry ) - should really include the associated wiring in that... ignition switches, much like the rest of the Prince of Darkness' offerings have been know to fail ...

OP - the { starter relay / fuel solenoid } and glowplug relay are only "connected" within the ignition switch. Do you have reason to suspect the ignition switch based on difficulties with getting the glow plugs to work ?

Disco1BFG said:

To be pedantic ( sorry ) - should really include the associated wiring in that... ignition switches, much like the rest of the Prince of Darkness' offerings have been know to fail ...

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@Disco1BFG you are right .... I have eited my post, adding superflous text in italics (for clarity in your case @Disco1BFG) , so that there is no need for you to read all the other posts to understand the context.

Daz300tdi said:

Hi thanks for getting back , pls understand I am feckin next to useless at engines , a work in progress you could say . Can you tell me what this will demonstrate? I am guessing if it doesn’t cut out then I have a faulty electric connection between solenoid and glow plug relay ?

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There is a solenoid operated valve in the fuel supply line in to the fuel injection pump. When you turn the ignition on, the solenoid is energised and the valve opens, allowing fuel to flow. When the engine spins it fires up. When you switch the ignition off the solenoid closes, stopping the flow of fuel, and the engine stops. As has been said it could be a fault in the circuit supplying the solenoid.
Another thought is that at the time your Defender was built they were fitted with an alarm and immobiliser. To satisfy certain insurance related standards (IIRC), the immobiliser was fitted with a further PCB of immobiliser trickery affectionately known as 'The Spider'. The dodgy soldering within the spider gave the same symptoms that you describe. It caused a lot of hassle and owners had the circuit removed and bypassed with a purpose built mini bypass harness CLINK THIS LINKY TO SEE EXAMPLE
This lived in a riveted metal box in the battery compartment under the passenger seat. You might have a rare 1996 300Tdi that hasn't had this removed.
Even if it's (the circuit) removed the little black box will still be there. You might be able to stick your finger up the hole that the main cable used to go through and wiggle the connector block in the linky above. I think I'm right in saying that if you can't, then it might still be in there and causing your ghostly gremlins.
EDIT
I've just noticed that LINKY says it's for a Discovery, but Defenders had them too.

If the immobiliser is still present and has not been bypassed, then a simple fix is dismantle the black box, pull out the PCB and reflow/solder the dry joints on it. They are easy to spot - It fixed my random cutout adventures - took me an hour or so….

That’s assuming it has an immobiliser of course, if not then I’m not much help!

Thanks for that , yes have immobiliser , actually it has two

I appreciate all your inputs , I will read em a few more times and look into the engine bay , stare at the steering wheel , scratch my head , and phone the spark and read em again in his company , try and read his changing expressions and go from there .!

Daz300tdi said:

I appreciate all your inputs , I will read em a few more times and look into the engine bay , stare at the steering wheel , scratch my head , and phone the spark and read em again in his company , try and read his changing expressions and go from there .!

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Is he an auto spark and been doing it for 15 years or there abouts? If so, he's probably aware of the Land Rover Spider issue from back then. It's a pain in the bum, I remember the hassle extremely well from back then when mine was doing it.

Next time it happens, take off the fuel filler cap and listen for air being sucked in, the vent may be blocked and causing a vacuum preventing fuel from being pulled out, try starting with the filler cap removed, (worth a try)

hi all so i got on eBay and bought a 300tdi mobiliser bypass thing £18, and duely pulled out the battery and unbolted the back box to the front of the compartment, drilled off the rivets and prised open the box ( I am assuming it has not been opened before what with the rivets and seal ) disconnected the box and plunged in the bypass .Put everything back in there . was mildly surprised when it started and has given no bother for a day or so . Feeling a bit rosey about this result , trying not to think of the lolly spent before I got this £18 plug in ; ( . So far so good hopefully sorted out the issue. Thanks for all the pointers folks .D

I had a similar issue D90 cutting out mainly when the wife was driving it. I did the immobiliser bypass which improved things immensely.
I also found that it had done lots of wading and that the back of the fuse board was covered in verdigris.

Ed

Daz300tdi said:

hi all so i got on eBay and bought a 300tdi mobiliser bypass thing £18, and duely pulled out the battery and unbolted the back box to the front of the compartment, drilled off the rivets and prised open the box ( I am assuming it has not been opened before what with the rivets and seal ) disconnected the box and plunged in the bypass .Put everything back in there . was mildly surprised when it started and has given no bother for a day or so . Feeling a bit rosey about this result , trying not to think of the lolly spent before I got this £18 plug in ; ( . So far so good hopefully sorted out the issue. Thanks for all the pointers folks .D

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Pleased it's worked out for you.