I recently bought a 1993 Honda civic with a h22a swap and p28 ecu not sure if its chipped. it has a check engine light because of oxygen sensor which is not on because of dc sport headers. Vtec is not kicking in, it runs fine but no vtec. Please help!
110% is still meant to use a O2 sensor "race header" doesnt mean a 4-1 or tri-y header etc , its going to have a hole with a nut in it somewhere like this that is for the sensor , if not go to the parts store and get a $0.25c O2 sensor bung and drill a hole for it after the collector and weld it on and run a sensor, the ECU needs it to make corrections on the engine , as far as the vtec goes id be checking the sensor itself and or the screen inside it , its based on oil pressure and IIRC if obd0 or obd1 it wont work if the computer is throwing certain trouble codes , aside from that Welcome To HondaSwap ! post some pictures of your ride , a eg hatch with a h22 should be ballsy