The air/fuel ratio feedback system of Nissan Skyline R32 which has a self-learning function is used and CO and HC density adjustment is not necessary because the correction range is wide.
 
Nissan Skyline CO, HC density inspection
 
Nissan Skyline R32 CO, HC density inspection
 
•  Warm up the Nissan Skyline R32 engine adequately and make sure the idle speed and ignition timing are standard. Check CO, HC density with CO and HC meter.
•  If values do not conform to standard perform the following procedures to inspect the air/fuel feedback condition:
1  In the data monitor mode, select "EXHAUST GAS SENSOR MONITOR" and "EXHAUST GAS SENSOR MONITOR (R)".
2  Set the engine speed above 2,000 rpm and make sure "RICH" and "LEAN" are displayed alternately.
 
Nissan Skyline R32 CO, HC density inspection
 
•  Short-circuit the self-diagnosis connector on the vehicle side (near fuse box installation). Otherwise, remove ECCS control unit and operate adjustment volume on control unit side. 
1  Set the ignition switch "ON" and use a lead line to short-circuit the CHK pin and IGN pin of the diagnosis connector for more than two seconds to release the setting. (Otherwise turn the ignition switch to "ON" and turn the adjustment volume on the side of the ECCS control unit to the right (CW) until it stops in the self diagnosis mode switching position (f) for more than two seconds and then return it to the original position.)
 
Nissan Skyline R32 CO, HC density inspection
 
Nissan Skyline R32 CO, HC density inspection
 
2  After warming up the engine adequately, raise the engine speed until the exhaust temperature warning lamp (or the red lamp on side of control unit) flashes (the flashing will start above approximately 2,000 rpm). The exhaust gas sensor output monitor (R) mode will be set. 
CAUTION:
The accelerator pedal of Nissan Skyline R32 must be pressed intentionally during idling to perform the inspection because the air/fuel ratio feedback control is stopped.
3  Make sure the exhaust gas temperature warning lamp or red lamp on the side of the control unit flashes in this condition.
 
Nissan Skyline R32 CO, HC density inspection
 
4  Use a lead to short the CHK pin and the IGN pin of the diagnosis connector for more than two seconds one more time to release the self-diagnosis mode. (Otherwise turn the adjustment volume of the ECCS control unit side to the right (CW) until it stops to select the self-diagnosis mode (D for more than two seconds and then return it to the original position).
Note: Refer the corresponding section for explanation of air fuel feedback monitor.