OBD-II GS with 4 O2 sensors; headers only have 2

[nightfire]

I've got 4 O2 sensors, but my new headers (building up my KLZE) only have 2 holes. Other than tapping new holes, do I have any options?

Can I wire two sensor cables together to piggyback off one O2 sensor?

[solo_ryder]

Well, there should be 3 sensor bungs on the OBDII headers, 1 on each primary and on that is near the flex pipe, the other one may be in the cat or after the cat converter. Your best option is to weld a new bung on where the old 02 was located as it seems you got OBDI style headers

[JoshVK]

should have 3? why?
stock has 2 sensors per bank
2 sensors are up stream and NEED to be there. the other 2 that are down stream dont bother with.. will throw a code on 96 ecu no mater what.

[nightfire]

should have 3? why?
stock has 2 sensors per bank
2 sensors are up stream and NEED to be there. the other 2 that are down stream dont bother with.. will throw a code on 96 ecu no mater what.

Hey Josh,

Are the upstream sensors the ones with 3 wires or 4?

[JoshVK]

should have 3? why?
stock has 2 sensors per bank
2 sensors are up stream and NEED to be there. the other 2 that are down stream dont bother with.. will throw a code on 96 ecu no mater what.

Hey Josh,

Are the upstream sensors the ones with 3 wires or 4?

the 3 wire.


Also 3 wire and 4 wire are almost the same. just ground the white wire in the 4 wire and it would be the same

[nightfire]

should have 3? why?
stock has 2 sensors per bank
2 sensors are up stream and NEED to be there. the other 2 that are down stream dont bother with.. will throw a code on 96 ecu no mater what.

Hey Josh,

Are the upstream sensors the ones with 3 wires or 4?

the 3 wire.


Also 3 wire and 4 wire are almost the same. just ground the white wire in the 4 wire and it would be the same

That would explain why I'm running in open loop mode.

*swaps O2 sensors*

BTW - What did you mean by don't bother with the other 2 sensors? If I tap two new holes downstream (ie. in the downpipe) will the ECU still throw a DTC?

[JoshVK]

unless you get spacers it will still throw a code.. they are just there to monitor that the pre cats are working, so if it reads outside of what it thinks is proper (the values you would get with working precats in) its going to throw a code,... so don't bother with em as you'll get a code either way...

[nightfire]

unless you get spacers it will still throw a code.. they are just there to monitor that the pre cats are working, so if it reads outside of what it thinks is proper (the values you would get with working precats in) its going to throw a code,... so don't bother with em as you'll get a code either way...

I didn't know we had pre-cats..

Interestingly enough, I've been running without them for a few days now (100km) and still no code. Sweet.

[Daninski]

So everything is still good with just two O2 sensors and not the lower two, good. If I ever get my headers I'll be able to install my ZE, I'll omit the bottom two sensors as well.