If it is K-Jetronic the cold start module is bolted to the block near the starter motor. L-Jetronic cold start is controlled by the EMU. I hope no 'expert' has robbed too much off the engine. Cold start injector (if it has one) is controlled by the starter switch and a temp/timer module near the other temp senders.
Good - Fast - Cheap: Pick any two.
E23 735i; E32 735iL (X 2 - 1 Alpine White and 1 Glacier Blue); E34 535i; E38 735iL; R50 Cooper; R55 Cooper Clubman.
E21 318i; E30 318i; E32 735iL; E34 535i; E38 730iL; E53 4.4i