EX wiring harness

[Sil VurFoX]

98 civic "HX".. swapped a 97 "EX" harness, engine, and computer into my "HX" to sell it off. But I'm stuck and throwing a code for secondary 02 sensor low voltage.

The "EX" has a sensor or something for the emission system by the fuel tank assuming that the oxygen sensor ties into. On the original EX car the secondary 02 sensor plugged into a spot just under the dash board that runs up by the guage panel.

The HX doesn't have this plug.. so I tried to wire it directly to the computer and 3 out of the 4 wires are good. But the black wire that is supposed to go back to the tank is messing this up. Can you guys help me out? Thanks!

 

[posol]

hx uses a 5-wire wideband o2 sensor. the ex uses a normal 4-wire, and is not wired for it.

 

[Sil VurFoX]

being that I have the EX engine, EX harness, and EX computer.. in the HX chassis is there a way I could wire this up? Seems like just that one ground wire is messing the whole swap up.

Or should I buy a HX computer and wiring harness and call it a day, to be used on the EX engine? They are both V-tec engines..

 

[posol]

just buy a 4-wire o2, and wire it up.

 

[Sil VurFoX]

The Primary 02 sensor is perfect.. no codes.

My secondary 02 sensor 4 wire that I just wired in.. 3 of the wires I took care of right at the ECU.. but the 4th wire which is black.. not sure where it goes. I tried to splice it in to the charcoal canister in the engine bay.. because they are on a common wire that go to the same spot. But after the car runs for a little while the cel comes back on low voltage.

What do you think.. throw a HX engine harness and computer back at it on the EX engine to kill the light? This is a "HX" chassis.. I just swapped all my EX stuff into it to sell it off.

 

[matt g]

maybe you can splice in the secondary sensor wires into the primary wires. i dunno if it will help, but it might.

 

[projekteg]

Originally posted by pissedoffsol@Oct 15 2004, 12:57 PM
hx uses a 5-wire wideband o2 sensor. the ex uses a normal 4-wire, and is not wired for it.

[post=402991]Quoted post[/post]​

the vx uses the 5 wire o2 sensor, hx has regular 4 wire for primary and secondary. did you ever think that maybe your sensor is bad? i know every time we throw a cel we think it's wiring, but sometimes it really is the sensor, that's what the cel is for

 

[Sil VurFoX]

The "EX" harness is a 4-wire primary and 4-wire secondary 02 sensor. The "EX" chassis has the secondary 02 sensor plug under the dash on the drivers side. I believe it runs up to the gauge cluster.. and eventually runs to the gas tank for some type of sensor.

The "HX" chassis has the 5-wire wide band Primary 02 senson and a 4-wire secondary sensor. The secondary 02 sensor plugged in out in the engine bay, directly into the harness.

I'm selling the "HX" car and took my built B18 turbo engine out and was trying to put it back to stock with the engine, engine harness, and computer out of my "EX".

Once I installed all the "EX" parts into my "HX" chassis.. I ran into a problem with the secondary 02 sensor cel. I've wired the 3 out of 4 wires according to the book. But the 4th wire, which is black is supposed to go to a junction block and back to the gas tank for a sensor. I don't know how to get around it.. that is why I'm getting the cel. I tapped it into the charcoal canister wire.. and the cel stays off for a few days.. then it comes back on.. low voltage.

I'm thinking about just buying a "HX" engine harness and computer and putting it back in the car and hoping this will solve this problem. If anyone has a better idea how to fix this.. I'm open to any suggestions. Thanks..

 

[Sil VurFoX]

Alright.. tired of this little yellow light glaring at me.

I found that the only difference between the two chassis are emission related to a sensor back at the gas tank on the EX model. Being that I put all the EX stuff in the car, the computer is looking for this certain sensor that I don't have.

I wired in a new 4 wire secondary o2 sensor and the light stays off for a few starts. Then it pops back on.. I tried to ground this wire to the computer and it didn't work. Should I try putting the 7.5 volts to it..?

How does everyone else install the "EX" engines and computers into different chassis with out running into this code? No matter what chassis.. the EX computer is going to look for this sensor that is only in that EX chassis.

Please help.. I'm tired of the yellow light.