Thread: 300Tdi keeps dying with strange symptoms when driving

Hi all,
I've got a bit of a problem which is really starting to confuse me on my 1995 manual 300tdi as auto electrics, even on something as simple as this isn't my strength. I'll try and list off most of the symptoms and any suggestions on where to look and where not to look would be appreciated.

About a month ago I was driving along normally and pulled up at a set of lights and the car just died. I turned the key off and on and none of the regular ignition lights on the dashboard (plugs, oil pressure etc.) lit up. It turned over but wouldn't start. After a couple of minutes of this all lights came back on the dash, I turned it over and off I drove.

it then got a lot more regular happening multiple times in a 10 minute drive and I worked out that if I ran a wire from the +ve on the battery direct to the injector pump solenoid that I could at least start the car and drive safely (stalling the motor to stop the car at my destination) until I had a chance to investigate what's happening.

It's now at a stage where even with the wire direct to the solenoid I'll be driving along and the dashboard dies, indicators stop working, the tacho stops working, speedo stops working, temperature gauge and there's no dash lights if I turn the key off and on again. The aircon still works as do the lights and wipers, horn, and hazard indicators and as long as I keep the ignition key turned on the immobiliser/alarm doesn't kick in with the flashing 'armed' light or siren. It's now not working more than it is and I need to sort it out. Unfortunately here in Darwin there's not many auto electricians who will look at a Disco with any idea of what it needs.

I originally thought it was something to do with the immobiliser but I dismissed that idea because as long as the key remains in the 'on' position there's no flashing immobiliser.
Then I started random thoughts - could the alternator be dying intermittently - I couldn't see that causing the whole thing to die and then restored perfectly. Could the battery be dropping a number of cells occasionally to the stage that there's nothing?
I've checked the earth strap, tight and clean, and I thought that if it was the earth then things like wipers and horn and lights wouldn't work.
My latest thoughts are something to do with a faulty ignition lock but I haven't pulled it apart yet to test whether the ignition wire loses power when the dash stops working. Could this be it?
I'll go through the wiring diagram again looking for something that feeds the circuits that are affected but the ignition barrel is something I could see as causing it. Or have I got no idea and just take it to the auto electrician and let him waste days on it?


Cheers

Any suggestions greatly welcomed as I'm planning to spend the weekend looking it over bit by bit.

Hi I had a similar problem, with my 300 tdi defender shutting down the engine. with no indication.

Turned out some of the alternator diodes were U/S.

fitted a new alternator, all good.

cheers simmo