1993 was first year of Zetec - I suspect it's a typo Ruut. No immobiliser on my '93. Dave's advice re: aerial close to the ignition key socket is good though. Don't know whether it is a passive or active key, if active, has the battery been replaced?
No battery in the Key, was told sometimes the key can go out of sink, try the spare key
Very much in the dog house, could be up for rehoming
Passive ones can't go out of sync. Active ones, the more complex variety, usually have a rolling code they are the ones that may go out of sync... Usually gives the dealer a load of to get them back again...
Graham (G4FUJ)
Sold L44FOR 4/4 Giallo Fly '11 MINI Countryman Cooper D All4 '90 LR 90 SW
to get them back again... 
