Oh dear, that's not good. Beyond my knowledge of this engine now.
@GrumpyGel will have a good idea hopefully. Mike
I love the L Series Skinney, but it never goes wrong - so I have no great knowledge of fixing it!
I've done quite a bit of reading up on it - so I know a fair bit about it factually - but fixing it my knowledge comes straight from threads on LZ! As other L Series owners experiences is similar to mine - there isn't a lot to go on.
@lyndbo how do you know air is getting in the filter? There are no glass bubbles on them to see inside - I'm presuming you're opening the bleed screw and when you pump it there's air comes out first? Could this air not be getting it when you open the bleed screw? If there is air getting in presumably it must be somewhere between the filter and pump - if it were from the pump or further 'forward', it would leak fuel once the pump was active.
I've done a bit of a search, and come up with this really useful thread for anyone with starting problems on their L Series....
http://forum.landrovernet.com/showthread.php/201446-freelander-l-series-engine-starting-problem
So a cheap quick fix is to replace the ECT (Engine Coolant Temp sensor). Be careful to replace the one the ECU goes by - not the temp guage one - they use different sensors.
The more time consuming, but doesn't cost anything, is to check the fuel pump timing. However, if your belts need replacing, replace them first or else it will all need to be done again. You may find that putting new belts on solves the problem anyway even if the pump timing isn't done at the time - but it should be checked anyway when doing the belts.
If these are OK, it may be fuel draining back out of the pump overnight as the pump needs fuel in the system to build pressure to get the correct timing. If this is the problem, what causes the drain back is another (more difficult to identify) problem. The leak back pipes do perish (I've replaced mine recently), but I'm not sure this would let air in to drain to the pump (it didn't on mine, although that thread does suggest it can). Possible drain through the injectors themselves I suppose. I'd have thought if air is getting in in the pipework upward of the pump, it would leak when the pump is running.
So, if you've changed the temp sensor (and it was the right one!) - I would strongly suggest you get the belts done. It sounds like they are in need of replacing and its a big gamble not to do them when they're needed. This alone has a good chance of fixing the problem - so long as the FP timing is done when the belts are done.