Thread: Rebuild 300tdi does start sometimes?

If you mean that the starter motor doesn't even operate, I'd start by checking that the power connections to the starter are fitted and done up properly. Also the earth lead to the engine block, and the earth lead on the battery itself. I'm assuming that one or more of these items may have been disconnected during the rebuild, probably all if you actually removed the engine.

Failing that, check the battery for having a dodgy cell, then after that you'd have to suspect either faulty starter motor, ignition switch, or immobiliser if fitted.

If it has a immobiliser fitted, they can develop dry solder joints inside on the printed circuit board.


Clean the old solder away from the joints and redo joints with fresh solder.


To get at the immobiliser which is fitted in most Discovery's from 1996 onwards, the radio must be removed to gain access to it.


The other place to look for starting problems is on the wire that goes from the ignition switch to the starter motor solenoid, that terminal which fits onto the spade lug goes open where the terminal is crimped onto the wire.


If it won't turn over again, get someone to wiggle that wire to get it to make contact and if that works the connector needs replacing.


All earthing points should be clean, with no paint in between the joint surfaces, free from dirt and rust.

Thanks guys, we cleaned all connections and we know its not the immobilizer, it hasn't done it for acouple of days now so no idea whats wrong