I just found a KA24DE but the seller doesn't include the harness. can I use my old one for KA24E?

 

Wheres BigVinnie, he'll know the answer.
I'd think that they are diff harness's.

 

they are different, i've pulled both myself

 

all of the plugs are different... thats why you need the harness and the ecu from the dohc motor if you are doing the swap into an older 240...

 

yea u also need to cut off the body harness clip with about 16 wires on it from the dohc body harness, cut off the brown connector thats on the soch body harness behind the glove box and color match the wires behind the glove box to the new plug. and start ur motor( u will not have a tach unless u change the entire harness and gauge cluster). 89 soch came with an analog tach not digital. it takes about 3 mins tops if u can wire.

 

as everyone else has stated, the two harnesses are not the same. you need a DE harness and ECU, along with a DE tach.