The Rywire B16A OBD0 VTEC Sun Harness is exactly what you need to add VTEC to your 1988-1991 Honda CRX when swapping in a B16A. This sub harness will add wires for your VTEC Solenoid, VTEC Oil Pressure Switch, 2nd Oxygen Sensor and Knock Sensor to your 88-91 CRX HF/Si. This is ideal for a B16A swap.