I just got a '92 Civic CX hatchbach. The previous owner swapped in a SOHC non-VTEC ZC short block. Everything on the emissions test easily passed except for NO (knocks) which was almost double. This is usually because the motor is running too hot, either too lean a/f ratio or a insufficient cooling system. The temp gauge sits where it should be so I don't think its the cooling system.

From what I've been reading around, the ZC makes more power than the standard North American non-VTEC D16 and D15, but the motor is still running off the stock P06 ECU. Could it be that the ECU is not injecting enough fuel because it can't compinsate for the additional power of the ZC?

I was thinking, if I were to install a FPR and turn it up a couple of PSI's that it might solve the problem.

Can anyone chime in and give their opinion?