i just started workin on a rx7 i had. i got it from a dude that had been drivin it and then left it parked under some leaves and some how the cat got so hot it caught of fire. so it charred the whole floorboard and some of the engine wiring. the car has ran once before after that by a mech of his. all the engine wiring looks screw up. it didnt affect the ecu though. is it hard to change out wiring harnesses in a 2cnd gen n/a i have a wiring harness from a 87 automatic rx7 to put in this 86 5spd. will the 87 harness work??