FastA$$Rx7

ok, i need some serious help, i put in a S5 motor tranny into my 86 N/A i put all the wiring on it from a S4 and a S4 ecu , i turn it over it want to idle reallr rich for a few seconds and then dies , should i 1 put on a S4 water pump and senser, or sumthing like that (like i was told) or 2 check the idiling pins and maybe replace , i was thinking it was a vaccum leak maybe from my homemade intake tube but i dout it ,,,,,,,,,, Any Sugestions????/