Here is my situation, I have searched, read and tried to apply fixes in all the articles pertaining to this situation that I can find. I am hoping someone can help me with this!
I have a 98 civic si (Canada) but was made late in the year so it's actually a 99 harness and obd2b. I have swapped in a b18c1 from a 2000 gsr, also obd2b. Now every time I crank the motor fuse 31 on the panel under the driver side cabin panel blows. From reading I understand this fuse powers ECU ICU and main relay. I think I have it narrowed down to ECU ( possible short on the blue/white wire powering or possibly a short down stream from ECU?) the reason I think that I has to do with ECU is fuse 31 does not blow when main relay and ICU are plugged in, only when I plug ECU and turn over does the fuse blow.
I don't think the short is in the ECU (integra) because I also plugged in the original ECU (civic) and both blow fuse 31.
The car ran with the d series motor but will not run since I swapped. There is fuel getting to the rail but no spark. Hope I have given enough info.

 

Wrong section moving it...

 

Ok thank you Dave & sry for the confusion. One more thing I can add is, the only wiring I have added / modified is adding the secondary butterfly wiring and performing the CKF bypass trick, .:FFS TechNet : CKF Bypass Trick :.

I have disconnected the secondary wiring but still blows 31. Yet to try removing the quick splices used in the ckf bypass.

 

Have I not followed some protocol or not included enough information? Surely I haven't stumped the entire Honda-tech nation!

 

Sounds like a bad ECU. Also remove pin A24 from ECU connector A and inspect it.

 

Thank you very much for the reply I will check pin 24, you think both integra and civic ecus are bad? They both blow fuse 31. The civic ECU was fine before I did the swap.

 

Be open to the possibility to avoid being led down a blind alley.

 

So would you suggest first get a new ECU & go from there? A side note is I am not getting an ohm reading from the blue/white wire on C plug

 

Carefully inspect ECU connector pin A24 first.

Pin C23? That is the VSS wire and is not likely relevant. What CEL codes?

 

I have yet to plug a reader in. I removed the immobilizer from teg ECU and do not have the dumbie board to instal yet. From what I understand I will get false codes on my reader until this board is installed.

 

I am a little confused here, my car only has the B & C plug. I understand that A plug is part of the cabin harness but I cannot find any plug that matches the pinout diagram for obd2b, pins or wire color. To add to my confusion the ecu i got with my swap (2000 gsr, also obd2b) had an A,B & C plugged into it. Bottom line is I do not know where to check A pin 24, starter signal switch

 

Civic OBD2b ECU connectors:

 

Thank you, I do have that connector diagram but no clip that matches "Connector A"

 

Post many nice pictures showing various views of the ECU connectors that you do see.

 

These are the plugs I am dealing with

 

This is the B & C plug

 

This is the A plug that came with my integra ECU. Nothing like this in the car.

 

 

So I think I finally am on track with what I'm dealing with. Feel free to chim in, any help is MUCH apreciated! This car is new to me so I dont really know its history. I cross referenced the vin on the car and that on the orginal motor (D16y8) that I removed for the gsr swap. Turns out the motor is out of a 99 ex or si (Canada) It looks like who ever did the swap used the b16a2 (obd2b) engine harness and ECU and plugged in the 98 (obd2a) cabin harness. This allowed the car to run but the speedo, tach, rad fan etc not to operate. In my original post I thought the cabin harness was also obd2b but am think this is not the case. Correct me if I'm wrong but this could also be the culpret with the blown 31 fuse, an 2a cabin harness mated with a 2b ecu and a 99 b16a2 engine harness on a 2000 gsr motor. It would also explaine my missing A plug to my ecu.

 

this is the one I believe Ihave, notice only the B & C plugs are present C133 & C134

 

So if anyone has any interst in this, this was in fact my problem. Removed 2b engine harness, swapped in a 2a harness and 98 gsr ecu and car is running now, no more blown fuse 31, thanks to RonJ for taking the time to help me out.