A friend of my recently bought a zc swap for his 91 Ef. Now he buttoned a lot of things up, and during the first start up the engine turned over but sounded like crap. Also on too of it, the car was throwing all types of check engine lights. Now last night, we redid the wiring and got the cel to go away, but while driving the car, it feels as it's losing power! We've tried messing with the timing and it was lined up correctly. If anyone can shed light on it, it'll be really helpful. Thanks!

 

Could be a thousand things, did you replace plugs and wires? Did you run a compression test on each cylinder? Do you know if the fuel pump is working as expected? O2 sensor can cause things to mess up as well, do you know which codes the ECU was throwing?

How was the car running prior to the swap, which components are new versus on there before?

Diagnose one step at a time. Process of elimination sometimes.

 

i wanna say plugs/wire/cap/rotor would be the easiest thing to do first if u havnt done them already. however because its a swap, i would make sure the tps is calibrated, map/tps/iac can effect idle/performance.

but a simple compression test will tell u the obvious if the motor needs to be rebuilt or not