my ls swap has bouncy idle.could it be because i still have the d15b7 ecu or do i need new plugs?im also gettin a check engine light.i have a ls auto ecu but just havent swaped it yet.this was the first start after the swap.

 

You need the ls ecu. A 1.5 soch ecu won't run a 1.6 dohc well at all. Think about it; what made you think the old ecu would run an ls motor well? Get that auto ecu converted to a 5spd and you'll be good.

 

d15b7 and ls r similar motors(no vtec but ofcourse ones a sohc and ones a dohc) so i though it would atleast run.i knew it wouldnt run at its full potential but didnt think it would idle badly.well ill just swap in the ls ecu.btw is it ok if i swap the ecu with out disconnecting the battery because my car has alarm and i dont like programing it when i hook the battery back up.thnx