93 with one O2 Sensor?? (1 Viewer)

[mylesprimo]

I posted this question a while back and never got a direct question. I plan on redoing my exhaust, and running a y-collector with either 2.5 or 3 inch output back to a high flow cat and either glasspack or magnaflow exhaust. My question is can I eliminate one of my two o2 sensors since they are both pre cat on the 93? I want to try to make it so both banks are running off of the the same sensor.

 

[IBCRUSN]

No, because each O2 sensor monitors a bank of three cylinders.

There is an option if you choose to remove an emissions device. Remove the PAIR valve, tubes, silencer and other parts associated with that system then cap the vac line, plug the air cleaner fitting. After all of that is removed relocate your O2 sensors to the PAIR tube bungs on the exhaust manifolds and away you go. Be sure to keep the appropriate O2 sensor with bank of cylinders it was originally tied to.

 

[mylesprimo]

Has anyone done this? I was thinking about moving that anyway. Will I have to buy new bungs, and run more wire the extra distance?

If anyone has pics of this setup...that would be awesome.

 

[cruiserdan]

No, because each O2 sensor monitors a bank of three cylinders.

There is an option if you choose to remove an emissions device. Remove the PAIR valve, tubes, silencer and other parts associated with that system then cap the vac line, plug the air cleaner fitting. After all of that is removed relocate your O2 sensors to the PAIR tube bungs on the exhaust manifolds and away you go. Be sure to keep the appropriate O2 sensor with bank of cylinders it was originally tied to.

I just compared an O2 sensor gasket and a PAIR tube gasket and all the holes line up so that could very well work. The gaskets are made out of different materials and I would use the O2 gasket. The exhaust would be hotter at that point than it is down below but I don't think it would make much of a difference. The trick would be re-routing the wiring since, I think, some of that circuit is shielded.

 

[cruiserdan]

Has anyone done this? I was thinking about moving that anyway. Will I have to buy new bungs, and run more wire the extra distance?

If you did it in the manner suggested above you would be fitting the sensors directly into the exhaust manifolds where the air injection tubes are currently fitted. If you intend to keep the PAIR functional then you would have to fit bungs to your custom Y pipe.

 

[mylesprimo]

Sensors have been purchased (thanks CDan) and once they arrive the new process will begin.

 

[cokidva]

Hey Myles,

Subscribed and waiting... I have all the gear to do this swap but not the time at the moment and it just passed inspection so I not toooo worried but I would like to see what you come up with.

Cheers!

 

[Firedog]

No, because each O2 sensor monitors a bank of three cylinders.

There is an option if you choose to remove an emissions device. Remove the PAIR valve, tubes, silencer and other parts associated with that system then cap the vac line, plug the air cleaner fitting. After all of that is removed relocate your O2 sensors to the PAIR tube bungs on the exhaust manifolds and away you go. Be sure to keep the appropriate O2 sensor with bank of cylinders it was originally tied to.

I thought about trying this with mine until i read this
Oxygen Sensor Design
I really don't know if it would make a bit of difference in the real world, but the o2 sensors were expensive enough that I didn't want to have to replace them all the time.

 

[IBCRUSN]

I did this on my '94 and haven't had any issues. As I stated above I removed everything visible pertaining to the PAIR system and plugged the silencer bung on the intake. On the off chance I return to a state which has emissions inspections I replaced the coolant tube on the right side of the block with one off of a '95+ without PAIR P/N 8720860161. Be sure to get the pipe gasket as well. Other than the plugged intake bung and vac hard line on the front of the head it looks like it came that way from the factory. If I get ocd I can fix the vac line and the intake bung may be used in the future for a compressor system.

I don't have any pics handy but I'll take a few and post 'em up.

Note: For those in states which have emissions inspections there may be legal ramifications.

****Edit: Added P/N of the '95+ coolant pipe "Pipe, Heater Outlet, B"

 

[IBCRUSN]

I just compared an O2 sensor gasket and a PAIR tube gasket and all the holes line up so that could very well work. The gaskets are made out of different materials and I would use the O2 gasket. The exhaust would be hotter at that point than it is down below but I don't think it would make much of a difference. The trick would be re-routing the wiring since, I think, some of that circuit is shielded.

Quite right, the gaskets are spot on. Once I found that out I had things changed out in an hour.

I wasn't concerned about the EGT temps because I've seen O2 sensors installed pre and post turbos and those systems generally run hotter than NA engines.

The wiring wasn't an issue either. In fact the only wire that had to be rerouted/reattached was the harness for the rear bank that goes over the tranny. I used some extra silicone .5" vac line to make chafe protection and routed it over the heat shield on the firewall.

I thought about trying this with mine until i read this
Oxygen Sensor Design
I really don't know if it would make a bit of difference in the real world, but the o2 sensors were expensive enough that I didn't want to have to replace them all the time.

Certainly a valid concern but I don't think this is too much of an issue on these engines, turbos for sure though. We're only talking about moving the sensors upstream ~24" and the overall temp is not likely much different in either location (closer to exh valve or in front of the cat).

 

[IBCRUSN]

Pics of revised O2 sensor installation. Apologies for the delay.

 

[cruiserdan]

Nice touch using the later heater pipe to "disguise" the lack of the PAIR.....

 

[mylesprimo]

I just finished mine today. I had a time routing the rear bank as I wanted to, but I finished, and no more codes, and now plenty of room for a york. I will post pics as soon as I can.

 

[IBCRUSN]

Nice touch using the later heater pipe to "disguise" the lack of the PAIR.....

It's not legal for sure but it has that factory look to it.

If I could just convince Onur to locate a set of 93-94 exhaust manifolds he could fix his O2 codes.

 

[cruiserdan]

I'm not sure that would help since the 95-97 sensors are upstream and downstream and are looking for different signals.

 

[IBCRUSN]

I'm not sure that would help since the 95-97 sensors are upstream and downstream and are looking for different signals.

Duh, I knew that. Maybe a dummy O2 sensor similar to what's available for modern day muscle cars?