strider380

I have a 96 civic ex coupe with a 99 ex motor in it. I used the 96 wiring harness and ecu.

The 96 wiring hanress and 99 distributor have different plugs. So I soldered the plug from my old 99 harness onto my 96 harness and plugged it into the distributor. I had a blue wire left over which is for the tachometer. (96 motor ran the tach from the distributor, 99 motor ran the tach from the computer) I soldered a connector onto the blue wire and ran it under the 99 distributor cap to an empty spade terminal (used for the tach on the 96).

I was so happy to start the car and watch the tach when I found it was still unresponsive. I noticed if I revved the motor to about 3 or 4k, the tach would go from 0, jump to 7k for a second, then back down to 0 and continue to be unresponsive. Any idea what would cause this? Thanks for any help.

Former User

Are you using the 99 EX OBD2b ECU? If so, you need to run a wire from the ECU to the tach.

strider380

Nope, I wish it was that easy, I am using the 96 wiring harness. So I had no idea what to do and opened the distributor cap. I found an empty connector on the 99 distributor. Comparing it to the 96 distributor on my blown motor, I found the blue tach wire goes to this connector. The distributors look to be identical. I thought the problem was thankfully solved until I started the car. Like I said the tach stays at 0 but if I rev it to about 4k it will jump up to 7k for a second. I also have a few check engine lights on that came with the motor swap. I gotta wait til I get enough money to rent the code reader since this car isn't registered right now. Any ideas?

Former User

So you have the 96 EX OBD2a ECU?

Check your solder/splicing job on the blue tach wire for a short or high resistance using a multimeter. Also open the distributor and make sure the blue wire connection to the ICM is clean and tight.

Another possibility is a bad tach or bad ICM.

You don't need a code reader. Click the CEL sticky at the top to learn how to pull codes by jumping the service connector.

strider380

Ok, I will check all of your suggestions. Theoretically tho, this should work fine...right? Thank you for the quick response and advice.