Hi, Guys and Ladies

So in my old 98 Si (ex us.) i dropped in a b16a2 from a 2000 sir, i sold the car a year ago and just bought it back, now i'm in the middle of taking the b16a2 and putting it in my 97 hatch, but for whatever reason the ecu only has 2 plugs it's missing "B" i don't see any cut wires in the harness and the car ran fine but with no vtec, anyone ever seen this before on all the ecu pinouts it shows 3 plugs, a,c,d for obd2a and a,b,c for obd2b i don't understand how the car ran because all the injector wires are in the "B" plug, is possible in the year that someone else owned the car that they converted it to obdo or obd1? but it still has a p2t ecu

 

OBD1 still uses a 3 plug setup for the ECU so converting it wouldn't of changed that.

 

thanks, i have been searching since posting, and have found out honda's use 3 plugs on the ecu,(obd0, obd1, obd2a, obd2b) i'm positive that mine had 3 when i swapped it in there 3 years ago, but man i'm confused to hell why it now only has 2 and even better how was it running

 

Are u using an EX harness??

 

so here's what i know now:
-the engine harness thats on it now has two ecu plugs one gray one blue
-blue is pretty much filled
- gray is well over 50%
-i have a p2t ecu looks to be unmoddified and has ABC and plugs d is blank

this is what came with the motor 3 years ago so is the normal em1 (99-2000 b16a2) wiring?

The plan or goal.....
-run a 97 obd2a wiring harness by lengthening proper wires/plugs
-make my own jumper using obd2a/obd2b ecu pin outs to run the obd2b ecu
-be able to check my codes and get proper fuel econimy/VTAK lol

anyone know wtf the engine and ecu i have and what to do on the cheap to make this run.... i need to be able to check my codes though, when it was in the coupe it ran fine, but had to jump wires to get the speedo, rpm gauge, and cooling fan

thanks

 

the 99-00 (obd2b) harness is two plugs .... the other gray one comes from another harness in the cab

the 96-98 (obd2a) harness is three plugs ... but you need a jumper to be able to use the p2t

it is possible to rewire the obd2b engine harness for that you need to hack it up and undo plugs and redo other ones ..... its a lot easier to use the 96-98 harness and just use a jumper from there

 

yeah 96-98 is OBD2a and 99-00 OBD2b.

you caaann change the underdash harness to a 99-00 underdash harness, or like stated.. you can just use the 96-98 engine harness, add wires for vtec and either RE-PIN the plugs to obd2b or use a obd2a->obd2b conversion harness.

 

Yep, you need a 96-98 harness to make things nice and easy. If you get an EX harness, that just makes it easier. You just have to extend a couple wires (VTEC pressure and solenoid, maybe front O2). Only drawback is you'd need to either buy a OBD2B-OBD2A jumper harness to use your P2T, go OBD1 and get OBD2A-OBD1 jumper harness or find a 96-97 Del Sol VTEC (B16A3) ECU. It will be a direct plug in for your Civic.

Ryan