I'm going under my 5 spd. swap and i ran the CEL cause it was on (cause of the torque converter) and it says my knock sensor. I was just wondering would a knock sensor prevent an engine from running?

 

A knock sensor code means the ECM thinks it's not working. Shouldn't prevent the car from starting.

 

It should run, however you'll get bad performance and bad gas mileage. It is a common problem in 4th gens. I think they cost around 65 bucks online and are straightforward to install but hard to reach.

those eyelids on your i30 look sick, good luck with the 5 spd swap.

 

I'd reset the ECU and see if it comes back. besides that, I agree with what markd248 said.

 

Haha I don't have eyelids just cefiros. I'll let you guys know how the swap goes.