JDM catalytic converter's oxygen sensor

[Zack Prelude91]

Dear Spiffy,

i did ask you about the extra gauge from my lude last time. Now i managed to remove the catalytic converter.I found that the oxygen sensor's wire is destroy and probably thats why the catalytic converter symbol in the cluster is light up.. Too bad the sensor is badly seized and the hex nut of the sensor is a bit small (18mm) compare those sensor in the upstream(22mm). My question is i want to replace it with a sensor just like in the upstream one.. do they all o2 sensor have same specification or same current? i attach 3 pictures including my extra used upstream 02 sensor that i want to it into the catalytic converter

Thanks

Cheers

[spiffyguido]

Not sure on the current of O2 sensors, but I imagine among Hondas they're all relatively similar. The big difference I do know of is that some O2 sensors have a different number of wires than others. I believe older Preludes have a 3 wire O2 sensor while new ones have a 4 wire O2 sensor. You'll be able to take a look at yours and count the prongs on the plug end of the sensor. Just get one with the matching plug and it will probably work just fine.

Does that help?

[Lude914ws]

hi spiffy~~

All o2 sensors in my prelude got 1 wire including that attached at the catalytic converter.Yeah true i try to cut the wire and change the plug..i will update you again.Thanks for the advise btw below is my prelude's pic.

[spiffyguido]

Lude914ws, thanks for dropping in and sharing your findings. Perhaps Zach will be able to learn from the work you did.

After doing some more research, I see that the 4 wire O2 sensors are in the OBD1 3rd generation Preludes. That's what mine has on the exhaust manifold. My car has a B21A1, so there is only one O2 sensor on the exhaust manifold, not two like the B20A5 which uses the single wire sensors. I can't recall how many wires my sensor at the catalytic converter has....in fact, I can't even recall seeing a sensor in the catalytic converter, but it's been a while since I've been digging around in there.

I did find the following conversion guide that might help: http://www.preludepower.com/forums/show ... p?t=303615

[Zack Prelude91]

i got this from another forum~~ its not oxygen sensor but CAT temp sensor~~~ im not sure what is the function of CAT temperature sensor?if its link to ecu~~there must be something to do with fuel management? i have read also from other forum saying that CAT temp sensor is not important just cut off the wire and ground it then the light will gone.Any idea spiffy?

[spiffyguido]

Not sure on cutting it off. Since it's a single wire sensor, it has to work by measuring the resistance through the sensor through the exhaust system acting as the ground. You'd have to know how much resistance the sensor itself gives to get an idea of whether or not you can just cut if off. If it doesn't work based on resistance and just turns 'on' when the cat converter gets hot, then you could probably just cut it off and ground the wire.

Good to know that what we're dealing with is a temp sensor. The single wire sensors always make me wonder because they have to operate without a return circuit. That's why the newer O2 sensors have so many wires. They have positive and ground leads, plus a circuit for the heater element that keeps the sensor at a constant temperature.