my buddy has a 90' prelude with a b20a5, he seized his old motor and had someone swap in another b20a5, but ever since the swap the car has a hard time starting... he has to pump the gas when he starts it up for a little while until it starts running fine, i am thinking that the guy that did the swap didnt plug something up right... but could it also be the iac? or what else would cause this problem?

 

Any cel's? What happens if he doesn't give it gas does it stall? How long before it idles fine by itself?

 

may be caused by fuel presure reg, or the fuel pump not holding pressure. the fuel system having to bleed up before correct operation !. this can be diagnosed by fitting a pressuregauge and allowing the vehicle to stand over night and check the pressure drop .