i have a 99' civic si, the motor is b18b1 with obd2b,ecu is p75 with obd1, use a obd2b ---> obd1 conversion harness.I went to emission, the computer over there won't connect to my ecu,it says communication fail.

1. Is that because my ecu is a obd1?
2. Can I get a P75 obd2a and a obd2b --> obd2a jumper harness?
3. With the jumper harness can I pass the emission?
4. If this way(3) is not gonna work, how can I fix this problem and able to connect with the emission computer?

 

The ecu you are using for your vehicle is for the OBD1 protocol.
It does not have DLC(data link connector)

Only the OBD2 protocol has these and IS A MUST for smogging any vehicle newer than 1996. The DLC shows the inspector activity of the readyness monitors, and if they cant monitor readyness or faults. No smog for you.
using that jumper harness makes your DLC non-responsive and obsolete.
You will need to source a 2000-2001 OBD2B Integra Ls ECU, PERIOD. Your DLC will then begin to stream the necessary data for guys like me to inspect and perform emmisions tests on the vehicle.
And please dont ask if there is a way to emulate the signal or someother, cause its out of the question.
GL