HondaPartsHero

Since I saw this post on here like 3 times tonite I wanted to make a reference post to send people too so the same info doesn't clog up the board all the time. Feel free to correct or add and I'll add it to the original post to not clog this post up:
OBD0 motor into OBD1 car

Method 1

1. Use OBD1-0 ECU adaptor harness with PR3 ECU
2 Use OBD1-0 distributor adaptor harness or swap plugs over from your OBD1 distributor to the OBD0's distributor
3. Add resistor box and solder the OBD0 injector plugs onto the OBD1 harness and use the OBD0 injectors
4. Use OBD0 B16A header and two 1 wire O2 sensors or OBD1/2 header and weld in two O2 bungs
5. If not an EX or Si run wiring for VTEC solenoid, VTEC pressure switch and Knock sensor (you'll have to add knock sensor regardless what model it is).

Method 2

1. Use OBD1 ECU (P28 chipped, P72 chipped, P30)
2. Use a B16a or B18C distributor (can't use OBD0 dizzy with an OBD1 ECU)
3. Use some OBD1 injectors from anything but a CX or VX hatch
4. Use a OBD1/2 B16A header
5 If not an EX or Si run wiring for the VTEC solenoid, VTEC pressure switch, and knock sensor (you'll have to add knock sensor regardless what model it is, unless you disable knock or run a P28), Also if you car is a CX model you will have to add wiring for a 4 wire O2 sensor.

OBD0 motor into OBD2 car

Method 1

1. Use OBD2-0 ECU adaptor harness with PR3 ECU
2 Use OBD2-0 distributor adaptor harness or swap plugs over from your OBD2 distributor to the OBD0's distributor
3. Add resistor box and solder the OBD0 injector plugs onto the OBD2 harness and use the OBD0 injectors
4. Use OBD0 B16A header and two 1 wire O2 sensors or OBD1/2 header and weld in two O2 bungs
5. If not an EX or Si run wiring for VTEC solenoid, VTEC pressure switch and Knock sensor (you'll have to add knock sensor regardless what model it is)
6. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 2

1. Use OBD2-1 ECU adaptor and use P28 chipped, P72 chipped, P30 or P72 for B18C/C1 motors
2. Use an OBD1 B16a or B18C distributor with an OBD2-1 distributor adaptor or convert the plugs from your cars distributor over to the OBD1 distributor
3. Use OBD2 injectors from your vehicle
4. Use a OBD1/2 B16A header
5 If not an EX or Si (99-00) run wiring for the VTEC solenoid, VTEC pressure switch, and knock sensor (you'll have to add knock sensor unless it is an SI).
6. If you have an auto car or a non VTEC model you will have to wire in for a 2 wire IACV as your's is a 3 wire.
7. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 3

1. Use an OBD2 ECU P2T from a 99-00 SI
2. Use OBD2 distributor from a B18C1 or B16A2, or an OBD1 dizzy from a B16A/B18C1 either swapping over the plugs or using a dizzy adaptor, can't use OBD0 dizzys on OBD2 ECU's
3. Use the OBD2 injectors from your engine
4. Use an OBD1/2 header
5. If not an EX or Si (99-00) run wiring for the VTEC solenoid, VTEC pressure switch, and knock sensor (you'll have to add knock sensor unless it is an SI).
6. If you have an auto car or a non VTEC model you will have to wire in for a 2 wire IACV as your's is a 3 wire.
7. You'll also need to trick the CKF at the ECU so the ECU won't throw a code (http://www.ff-squad.com/technet/ckftrick.htm)
8. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

OBD1 engine into OBD0 car

Method 1

1. Use OBD0 ECU PR3/PWO
2. You must use an OBD0 distibutor with the PR3 ECU from an OBD0 B16A
3. Use OBD0 injectors from an SI/EX
4. Use OBD0 B16A header and weld in bungs for 2 O2's
5. Add wiring for VTEC solenoid, VTEC pressure switch, knock sensor, and 2nd O2. For B18C1 engines you must either use a Skunk2 type manifold or find a way to make a switched ground switch to open the IAB's.

Method 2

1. Use OBD1 ECU with an OBD0-1 ECU harness
2. Use OBD1 distributor with OBD0-1 dizzy harness or swap plugs over from your cars distributor to the OBD1 distributor (EX/SI/HF/all integra models only)
3. Use OBD0 injector but you must keep the injector resistor box or use the OBD1 injectors (solder OBD1 plugs onto the OBD0 harness) and eliminate the injector box.
4. Use OBD1/2 B16A header
5. Add wiring for VTEC solenoid, VTEC pressure switch, knock sensor, and 2nd O2. For B18C1 engines you must either use a Skunk2 type manifold or find a way to make a switched ground switch to open the IAB's.

Method 3

1. You can use an OBD2 ECU but I won't go into it because most people don't go this way.

OBD2 motor into OBD0 car

Method 1

1. Use OBD0 ECU PR3/PWO
2. You must use an OBD0 distibutor with the PR3 ECU from an OBD0 B16A
3. Use OBD0 injectors from an SI/EX
4. Use OBD0 B16A header and weld in bungs for 2 O2's
5. Add wiring for VTEC solenoid, VTEC pressure switch, knock sensor, and 2nd O2. For B18C1 engines you must either use a Skunk2 type manifold or find a way to make a switched ground switch to open the IAB's.
6. Convert over plug on your OBD2 alternator to the OBD0 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 2

1. Use OBD1 ECU with an OBD0-1 ECU harness
2. Use OBD2 distributor with OBD0-2 dizzy harness or swap plugs over from your cars distributor to the OBD2 distributor (EX/SI/HF/all integra models only)
3. Use OBD0 injector but you must keep the injector resistor box or use the OBD2 injectors (solder OBD1 plugs onto the OBD0 harness) and eliminate the injector box.
4. Use OBD1/2 B16A header
5. Add wiring for VTEC solenoid, VTEC pressure switch, knock sensor, and 2nd O2. For B18C1 engines you must either use a Skunk2 type manifold or find a way to make a switched ground switch to open the IAB's.
6. Convert over plug on your OBD2 alternator to the OBD0 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 3

1. You can use an OBD2 ECU but I won't go into it because most people don't go this way.

OBD0 motor into OBD2 car

Method 1
1. Use OBD2-0 ECU adaptor harness with PR3 ECU
2 Use OBD2-0 distributor adaptor harness or swap plugs over from your OBD2 distributor to the OBD0's distributor
3. Add resistor box and solder the OBD0 injector plugs onto the OBD2 harness and use the OBD0 injectors
4. Use OBD0 B16A header and two 1 wire O2 sensors or OBD1/2 header and weld in two O2 bungs
5. If not an EX or Si run wiring for VTEC solenoid, VTEC pressure switch and Knock sensor (you'll have to add knock sensor on any other models)
6. If your vehicle is an auto or non VTEC you'll have to convert over to a two wire IAC
7. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 2

1. Use OBD1 ECU (P28 chipped, P72 chipped, P30)
2. Use a B16a or B18C distributor (can't use OBD0 dizzy with an OBD1 ECU)
3. Use some OBD1 injectors and solder OBD1 plugs onto the OBD2 harness or use your OBD2 injectors
4. Use a OBD1/2 B16A header
5 If not an EX or Si run wiring for the VTEC solenoid, VTEC pressure switch, and knock sensor (you'll have to add knock sensor on any other models),
6. If your vehicle is an auto or non VTEC you'll have to convert over to a two wire IAC
7. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

OBD1 motor into OBD2 car

Method 1

1. Use an OBD2-1 ECU harness with a P28 chipped, P30, or P72 for B18C1
2. Use either an OBD1 B16A distributor with an OBD2-1 dizzy adaptor or swap plugs from your OBD2 dizzy over to the OBD1 dizzy or use a OBD2 dizzy from a B16A or B18C
3. Use your OBD2 injectors
4. Use an OBD1/2 header
5. If not an SI or EX run wiring for VTEC solenoid, VTEC pressure switch and knock sensor (you'll have to run knock sensor on any other models). On B18C1 you'll have to wire up for IAB's also.
6. If your vehicle is an auto or non VTEC you'll have to convert over to a two wire IAC
7. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 2

1. Use a P2T ECU
2. Use either an OBD1 B16A distributor with an OBD2-1 dizzy adaptor or swap plugs from your OBD2 dizzy over to the OBD1 dizzy or use a OBD2 dizzy from a B16A or B18C
3. Use your OBD2 injectors
4. Use an OBD1/2 header
5. If not an SI or EX run wiring for VTEC solenoid, VTEC pressure switch and knock sensor (you'll have to run knock sensor on any other models). On B18C1 you'll have to wire up for IAB's also.
6. If your vehicle is an auto or non VTEC you'll have to convert over to a two wire IAC
7. Convert over plug on your OBD0 alternator to the OBD2 style (http://img.photobucket.com/albums/v130/fobtions/alt.jpg)

Method 3

1. You can use an OBD0 ECU but is not recommended