I have a 1993 Honda OBD1 with a D16Y8 engine. I replaced the engine wiring harness because the original one was in very bad condition.The serious problem is this:🔥 The P28 ECU starts smoking, specifically from a component labeled R77, every time I plug it in.I have already confirmed that it’s not the fuel pump or the main relay, and the smoke appears as soon as I connect the ECU and turn the key to ON.Here are the tests I’ve done:With the ECU disconnected and the key in ON, the fuel pump does NOT prime (which is correct).When I ground the fuel pump relay control, the pump does turn on.I’m looking for help to:Confirm the correct pinout for a P28 OBD1 ECUIdentify which wire could be crossed or miswiredKnow if anyone has experienced something similar after swapping to a new OBD1 harnessGet recommendations before plugging the ECU back in and completely frying it 😅Any help would be greatly appreciated 🙏

 

The inside of your ECU looks dreadful... was it sunk in a lake or has it been stored for 25 years in a dusty location without a lid on it ? It may not be your wiring... it could simply be a bad ECU. Have you plugged it into a known good running Honda/Acura and checked to see if it still smokes ?

 

No, friend, it's just that the computer had already been modified and they didn't seal it properly, and dust got in. I just bought the car, which was in pretty bad shape, and I'm only just starting to maintain it. The car used to start, but the wiring harness was badly damaged. This problem started after I replaced the harness.

 

What did the replacement engine harness come from ? Did you have to repair any wiring ? Do you see any modified wiring on it ?

 

I didn't have to repair or cut anything, I simply removed the old harness and put on the new one.

 

Yikes !!! You bought a really cheap conversion harness and expect that it is perfectly wired ? It is quite possible that something is incorrectly wired in your conversion harness... especially at the plug which connects to your fuse box.