so i have a 91 civic that i swapped a d15b1 into because i bought car for 200$ and the motor in it had a huge gash in one of the cylinder walls. so i got the d15b1 in my car and got it running and then realized that cylinder number two isnt firing. i have the d15b1 wiring harness on the motor but its being ran off the d15b2 ecu. could that be why cylinder number two isnt firing? it is getting a spark, but when you pull the wire from the valve cover nothing changes. it only does this with cylinder number two. so could it be the ecu or something else and if something else what could it be? the motor was compression tested and it said it almost in just about 150 in every cylinder. the lowest i saw was 148

 

You could have a bad spark plug or wire or a crack in the cap making the spark for #2 weak. Or an air leak at the intake gasket making cylinder 2 too lean. The DPFI system doesn't have separate injectors per cylinder so it's not going to cause just one cylinder to misfire.

Check compression again just to double check.

 

brand new spark plugs and brand new wires. didnt do anything about the cap and rotor but i plan to replace them soon. also i got a valve cover gasket set and it didnt come with the four little gaskets for the top of each clyinder so i had no choice but to rvt them. but i can try and replace those soon too. ill check for an air leak though