I am putting this message up for mate's 3.9 disco he bought a few months back. When first purchased the car ran great - someong has installed a mallory ignition system and all was well. Then the problems started...will not start, try again in 10 minutes or next day, still won't start, try again the day after and it starts...Runs for five minutes or three days and then stops, this is while driving. Driving along either a 100 yards from the house or next day and she suddenly stops. On first name terms with the breakdown people, they suggested various sensors which do not appear to exist - like under the dashboard or at the back of the engine near the sump. Tow home each time.
When trying to start her up (without luck) there is no spark. New coil tried and she started but then the problem returned. Live wire to coil is actualy live but still no spark when turned over. Checked the wires from the disi and there is a good earth. Also tried an extra earth from the battery term to engine. Also no one off spark from the coil ht to block test..
Sorry to waffle on and thanks for any ideas.

 

Check out your Knock sensors on each lower side of the motor. Make sure they are connected. Then unplug them and turn the motor over, see what happens. At first I thought Fuel pump until you were talking about electrical ignition.

 

There are NO know sensors on his mates truck, it has a distributor.
Here is your problem, I am assuming they have not changed this when they put in the new dizzy.
Amplifier Module Relocation Kit | Land Rover Engine Parts at RoverParts.com

Track his down, buy a new one and you can move it yourself. It gets heat soaked and dies, when it is on its way out it can cause all kinds of havoc.

 

Thank you all for trying to help but where is the amp module. It's not next to the disi or behind the lights near the coil. The disco is supposed to have a mallory disi but cannot be sure.
Would the amp module have been replaced and be inside the disi now ....

 

That I do not know.
Land Rover Discovery I Engine Parts Available from RoversNorth.com

Distributor Kit - Mallory Performance Electronic Unilite | Land Rover Engine Parts at RoverParts.com

I do not know if the amp module is inside the new dizzy or not, but if it is red like in the pic then that is the Mallory dizzy.
I do not know exactly where the amp module is supposed to be located, if you go to the tech section ontop of the DI page there is a link for a free download of the RAVE shop manual.

 

Thanks for the link info. It is a red dissi so would assume a Mallory -
Thanks again

 

Let us know when you get it figured out.

 

My mates not into computers so I have been doing some googling. One idea I came across but not yet checked is wires shorting out inside the dist when the vac is advanced .........

 

That is possible I suppose.

 

Will report back in due course.
Thanks