I have been having problems with the wiring. I know that markj has a thread but I have a different setup. jdm b18c... I am using a 99-00 si wiring harness and a obd2b to obd2a conversion harness with a usdm p72ecu. what all do I have to change in the wiring ect ect. I have been messing with the car for a while and would like to get it running please help!

 

Get an obd2a wiring harness. 96-98 and 99-00 harnesses are different.

 

Why would it matter if he use a 99-00 si harness? (not being a DH)

I would assume that if he changed from the 96-98 to a 99-00 SI harness it should work since the engine harness is a one piece harness. He might have the wrong adapter harness for the ECU that he is running.

OP can you give some more information on what you have done, not done, and what the car is doing or not doing.

 

Because they're different.

99-00 harness has 2 ecu plugs on the engine harness, and a green connector which connects to the underdash harness which has the 3rd ecu plug.

96-98 harness has 3 ecu plugs on the engine harness, and a green connector to connect to the underdash harness.

 

Now that I think of it you are right about the 99-00 harness connecting under the dash. I have not looked a at 96-98 harness in a long time so, I cannot picture it in my head.

 

Yeah... I went through the same stuff as the OP is going through on my old hatch like 3 yrs ago. It ran but with a solid CEL. I tried to pull the code and the CEL did do anything. Went to change ECUs and noticed that there were only 2 plugs that plugged into the ECU. Changed the main harness and it ran fine.

OP I pm'd you back.