Ok I have a 1994 HB OBDI and i need to get the OBDII B18B in what are the issues. I have the complete LS integra OBDII B18B so i got the ecu harness engine and all......do i rip my OBDI wiring out with engine and replace everything with OBDII???....sorry for the confusion earlier.

 

the best thing to do would be to sell your ecu that came with the obd2 ls, and then purchase a p75 obd 1 ecu. That is what I would do if I was in your case

 

if i do that then.........would i need to change my harness?...would i just have obd1 harness, obd1 ecu and obd2 engine?

 

you just use your factory harness. It's not really the engine that is obd2, just the electronics on the engine. I'm not sure if all the plugs are the same however.

 

most everything will be exactly the same. you will need to extend your intake air temp sensor wires and convert to a 4 wire o2 sensor but other than that everything should plug right in. Just helped my friend with a b18c into his 94 hatch a couple weekes ago.

 

like said above, use your car's harness from the ECU to the shock towers, then the engine's harness from the shock towers to the engine. Then sell the OBD2 ECU and pick up an OBD1 P75.
It also depends on which HB you have. CX/DX/SI/VX. they all have a different amount of wires run in them all ready. the CX will require two wires to be run from the ECU to the engine harness at the shock towers. the others should have enough wires to make everything work.
It's not completely plug and play, but not far from it.

 

Yeh its a CX ....i appreciate all the info u guys given me.

 

what year is the B18B? I'll run through the ETMs tonight or tomorrow night for you an let you know exactly what you have to add/move.

 

b18b = 94+integra ls,gs,rs

 

94-95 are OBD 1 so im guessing his engine is 96-99