I have recently swapped a B18C5 motor into my 99 Civic SI. I went to get it inspected and there is no OBD2 communication. Could someone give me some ideas to why that would be? If it matters the serial number from the ECU it came with is 37820-P73-003

 

That appears to be a JDM ecu. Those will not communicate with a US scan tool.

 

Yeah i just saw a bunch of stuff about that. It was pretty difficult to find. Its a jdm motor and ecu. I know its not likely but is there any way to make it so it can be compatible with OBD2 or is just not possible?

 

You'll need a USDM ECU in order to pass. You'll also need to be very lucky in terms of who does your inspection, if the guy isn't retarded he'll realize that you've done a motor swap and send you to the referee, in which case you'll need a lot of other parts.

For this though it looks like the ECU out of a Integra Type-R should work.

 

could you give me a number or code for the ECU i should use?

 

Sorry for the double post. But i have an inspection guy thats pretty cool in terms of letting things slide. We just need the ECU to establish a connection with the OBD2 computer. Also I heard that a USDM ECU is not compatible with a JDM B18CR (C5) motor. Is that information i heard accurate? Thanks for the help.

 

Only thing Google shows me really is this: http://hondaswap.com/reference-mater...cu-list-29129/ Seems to indicate that the P73 ECU should work.

So far as I know the computer should plug right in and work, but I could be mistaken about that.

 

The car runs great. But when it comes to the inspection, the ECU wont establish a connection.

 

Did he bypass the OBD2 functional and obtain an emissions reading? Usually the JDM motor/ECU setups don't pass our dyno tests, curious to know if yours did.

 

USDM ECU should work with the JDM motor for the purpose of passing emissions. I wouldn't run the USDM ECU on a daily basis. There are 2 things you may have to do. You may have to swap the JDM VTEC solenoid with a USDM VTEC solenoid. The next thing you'd have to do is this:

http://technet.ff-squad.com/ckftrick.htm

I would find a OBD2A P73 USDM ECU and buy a OBD2B-to-OBD2A jumper harness so you can run the ECU. The reason you need OBD2A is so you don't have to worry about the immobilizer.

 

thanks for the info. but we havent gotten any kind of reading because it wont communicate. I had to buy the jumper harness so i could use the ecu in the 99 si. So if i got a USDM ECU, switch the VTEC solenoid to USDM, and splice the wires like in the link you provided, i should be able to get communication.

 

I know. That's because JDM ECUs don't have the correct programming to allow it to communicate with any US OBD2 Scanner. It just flat out won't work. The OBD2 JDM ECU is pretty much an OBD1 ECU with OBD2 connections. You have to use a USDM P73 OBD2A ECU and it will communicate with the scanner. You can even use the stock 99 Si ECU just to pass the scanning part, then swap the ECU back to your JDM one. But even if you do that, you'd still have to swap out your VTEC solenoid and bypass the crank fluctuation sensor like I posted.

 

I know i was reffering to lord yod with that. but you have been great help. thanks

 

This bolded part would be pretty much the same thing as doing the entire test with the USDM ECU, because of the way the smog inspections work (it plugs into the computer while doing the dyno test).

Though I actually just realized that I am only assuming the OP is in California, anywhere else the rules are different.

 

I'm in NC...