Yeah, I searched, but yeah, I am smooth brain and still need answers from the hive mind.

So I read this: https://honda-tech.com/forums/honda-...3/obd-1028824/

I have a 90 Si (bone stock, bad rings tho), which is OBD0 and a 99 B16A2 (OBD2b).

What kind of ECU should I get? From what I understand, using my factory harness for the D16 and modifying it would be best, but I also have the harness that came with the B16.

So my question: Which OBD do I go with? Which harness? Which ECU? I want to do the least amount of work possible, this isn't a high HP crazy build, just a stock B16 w bolt ons.

Cheers!

 

You'll have a few options. You have an Si, so you have MPFI already so thats a good start, and should not need to swap or chop up your stock harness too bad.

The below isn't intended to be comprehensive, but should give you a good enough idea to make a decision on what way to go.

OBD0: This will require the least amount of modification to the harness, but your tuning options will be limited if you decide to tune it later. You'll need to source an OBD0 B16 distributor, an OBD0->OBD2 alternator adapter, and possibly the coolant and oil pressure sensors (not entirely sure if they are the same between OBD0 and others). The D16 injectors should be the same size/flow and can be swapped to the B16, retaining the resistor box and original injector plugs. You can then get an OBD0 B16 ECU and it should be close enough to run the B16A2. (You could chip your ECU, but it won't have the provision for VTEC - it might be possible to add, or rig up something else to control VTEC as well.) For VTEC you'll need to run the signal wire for it as well. O2 sensor for OBD0 is single-wire and the D16A6 one should work as well.

OBD1: It's better supported and you'll have more tuning options, like Hondata, but can get more expensive w/ OBD1 ECU. The OBD2 distributor can be used so it may end up being a wash. You'd need a OBD2 to OBD0 ECU harness adapter, distributor adapter, alternator adapter, and might need to swap over some of the sensor connectors from the OBD2 harness. As w/ OBD0, the injectors from the D16 can be used here too. Depending on the ECU conversion harness, it may come with a sub-harness for the O2, VTEC and other OBD1 specific things, otherwise you'll need to run the wiring for those.

OBD2: Converting to OBD2 is possible since you have the full harness, but I wouldn't know where to start on our chassis. It would be messy to route the OBD2 harness, and would make it harder to return to stock.