Second O2 sensor wiring issue

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casinophil

New Member
I just installed a 98 EX engine into my 99 DX body so i had to use a OBD2B to OBD2A ecu jumper. I used a 99 ex harness to elimanate wiring in V-Tec. But by doing that the harness doesn't have any second O2 sensor wires on it it's on the 99-00 ex/si cabin harness which i don't have. So i have to wire it into the harness at the ecu connectors manually. I've found this information about it .:FFS TechNet:. ECU & WIRING OBD2 2nd 02 Sensor Wiring, but when i go to install the lengthened wires from the sensor into the ecu connectors there are already wires there. So im wondering do i remove them and replace them with my lengthened wires or will it cause whatever those wires are connected to stop working. Or should i just splice into the existing ones at the connector and what issues might that just cause? I'm currently running the engine without it connected so the sooner i can get this info the better.
 

katman

Member
I just installed a 98 EX engine into my 99 DX body so i had to use a OBD2B to OBD2A ecu jumper. I used a 99 ex harness to elimanate wiring in V-Tec. But by doing that the harness doesn't have any second O2 sensor wires on it it's on the 99-00 ex/si cabin harness which i don't have. So i have to wire it into the harness at the ecu connectors manually. I've found this information about it .:FFS TechNet:. ECU & WIRING OBD2 2nd 02 Sensor Wiring, but when i go to install the lengthened wires from the sensor into the ecu connectors there are already wires there. So im wondering do i remove them and replace them with my lengthened wires or will it cause whatever those wires are connected to stop working. Or should i just splice into the existing ones at the connector and what issues might that just cause? I'm currently running the engine without it connected so the sooner i can get this info the better.

not sure if you solved your wiring issues or not, but yes, just tap into the existing 2nd 02 wiring your EX harness has.
 
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