i have a mk4 1.25 zetec, i bought it with a blown engine i got a new engine and fitted it but i could'nt get the engine to turn over so i took a wire off the battery to the starter motor and it turned over then got it to start by turning the key and touching the wire on but once it had run for a while we turned it off and tried to start it normally and it still didnt turn over.

Anyone heard of this before or got any ideas of what it could be?

cheers