Secondary 02 sensor wiring?

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S

Sil VurFoX

Member
Using a 97 "EX" engine wiring harness.. how would you wire for the Secondary 02 sensor? The Primary 02 sensor plugs in... but there is no plug for the Seconday 02 sensor.

The "EX" chassis has the secondary 02 sensor plug at the dash that runs who knows where..

I read the Honda book and wired 3 of the 4 wires directly to the ECU.. but the 4th wire (Black) that is supposed to go to charcoal canister / junction block.. I tapped in to it under the hood and I still get a low voltage CEL.

I put the "EX" engine, "EX" engine wiring harness, and "EX" computer in my "HX" chassis.

Any thoughts appreciated..
 
you need to be more specific about what you have.

car year make model?
4-wire primary o2?
motor?
and the 97 ex wire harness?
 
The car is a 98 Civic "HX" I had a 98 Teg LS turbo in it.. so I ditched the "HX" engine wiring harness and computer when I did the original swap. I ended up using a "DX" engine wiring harness at the time. Now I've had problems with the chassis of the car splitting the spot welds at the core support so I'm trying to put it back to stock. Since I also own a 97 Civic "EX" I decided to just swap the engines and electronics from car to car.

So currently I have a 98 Civic "HX" with the 97 "EX" engine harness, "EX" engine, "EX" computer.

The "EX" engine harness doesn't have the secondary 02 sensor wired in it. They actually have a plug under the dash that goes up toward the gauage cluster. I have a Bosch 4-wire 02 sensor new.. so this is how I wired it up.

White- S02S directly at the ECU
Green- SH02SG directly at the ECU
Black- S02SHTC directly at the ECU
Black-

1. Could go to the junction connector on the (CX,DX,HX,LX) model then to Evaporative Emission Purge control solenoid valve.

2. Could also go to (EX) the Evaporative Emission Bypass Solenoid Valve, then to a 7.5A switched power source before it ends up back in the same junction connector as the other models do.

So this last Black wire.. I ran it straight out to the engine bay.. and connected it inline to the Evaporative Emission Purge control solenoid valve. Doing this the car will drive fine no CEL.. but the second or third time you start the engine the CEL will go back on. Where would you suggest I wire it back to?

I can't swap it back to OBD1.. emissions will not let me. I've been in trouble for this already and have the history on this car for doing it.
 
4th wire.. has been grounded to the chassis.. and it still has the CEL for the secondary 02 sensor, emission fault.. I'll ge the code numbers tonight.

The book is showing the wire going to a 7.5 amp fuse and some emission control selonoid..? Should I put a switchable power source to it..? I just put a brand new 02 sensor in it.. thought that might be it. It's not.

What do you think?
 
maybe this is an old forum.. but i happend to have the same troulbe anyone can help.. wat do i do about the secondary o2 sensor.. where to i plug it.. Thanks
 
being a 96 and up there are not many tunning options.. so if you convet it you have many more options and you dont need the other O2
 
bought 98 ex engine w. ex wires and ex ecu.. i did the swap and the primary o2 sensor is plug and play but the secondary o2 sensor cannot find... i searched and i found that A5 on the ecu is the plug for second. o2 sensor but since the sensor has 4 wires.. which where does it go into the ecu.. just to mention the o2 is stock so it has stock wire colors.. please help me to finish this swap...

*second since i dont have a catconv for now. Is second o2 sensor is pluged at the end of the headers is it going to be fine? or is the engine goin to run poor or rich on gas?
 
if wana convert to 0bd1 i have to get new ecu.. and obd2a-obd1 wire conversion would cost me money.... i just need to know which wat wire to slice and connect.. it would cost me time,wire and tape.. =)
 
the second should come in over the cat where the heat sheild is.. i think all you have to do is plug it in but im not to sure.
 
i have dx chasis.. so its different.. the second o2 used to be in the engine bay.. the ex chasis it has at the cat in the back..
 
i apritiate that.. im sure it would be help for other pple in the future..
 
obd2 secondary o2's are NOT heated, and are single or double wire.
4-wire for primary
1 or 2-wire for secondary.
 
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