A friend of mine put a built B18C1 12.5 to 1 compression swap into his 90 CRX. He is running a PW0 chipped ecu. Ever since the swap has been completed, it has thrown a code 23 (Knock Sensor). He tried changing the knock sensor and it did not help. He also tried running the wire from the knock sensor straight to the ecu to make sure the wiring was correct. It didn't help. Anyone have any suggestions on what could be the problem?

 

That is pretty high compression. What kind of gas are you using? You are not using 91 octane are you? With that kind of compression I would suspect that you would have to run race gas. Try some high octane race gas(ie. 100+ octane) and see what happens. Race gas is a little expensive but I would still give it a try.

 

Make sure he is running shielded wire. I had the same problem after my swap and it ended up being the wire was not shielded.

 

my knock sensor broke, try using chiped ecu ie.. skunk2 for which i dont belive it looks for knock sensor, i switched and no more code! good luck, eric