TD5 starting issue

Hi all, I have been driving my father-in-laws TD5 90 for the last few months as I've not yet finished my 110 project and I finally managed to get rid of the freelander, anyway the engine cover was in the back as it hadn't been replaced when he had some work done on it so I decided to put it back on. Before I replaced it she started 1st time every time on the button no probs, but after putting the engine cover back on you switched it on engine management light then glow plug light would go out as normal switch ignition to start and there's a pause then the engine starts. Take the cover back off and she starts 1st time again, I think the cover is catching something somewhere but I don't know what has anybody else encountered this problem
?
cheers Ian

Sounds like a bad connection somewhere. Injector harness plug at the front of the engine?
Probably full of oil. Not sure if refitting the engine cover would affect it though.

Cheers lightening did it without cover on this morning so fetched that plug off and cleaned it see if that does any good.
cheers Ian