02 Sensor location

[tcianci]

Calling this garage-related is a stretch but my truck is, after all, in my garage. I'm preparing to install the engine, a Chevy V-6 with dual exhaust and a crossover pipe between the 2 sides. Since the engine is running TBI, I need to install an 02 Sensor but I''m not sure if it needs to be in the crossover pipe or will one side or the other be OK?

 

[stinkity stoink]

Usually in one of the exhaust manifolds. If you are running headers with no bung I would put it in the drivers side pipe as close to the collector as possible. I am pretty sure depending on youre injection set up (unless heated 02 sensor) the quicker it heats up the faster it goes to closed loop.

 

[Carguy99]

If I may stick my head in, place it in the crossover.

 

[tcianci]

Whew! Now I'm as clear as mud on it! But I did check a couple DD's and called another guy I know. He said as close to the exhaust manifold as possible too. It turns out that The drivers side pipe from the manifold to the crossover is not welded to the crossover yet so I can slide it out as soon as I determine a position for the sensor that won't interfere for anything else and allow it to be removed later if needed.

I posted this question over on the H.A.M.B. too but it was thrown off quicker than a cheap prom dress. I got my *** handed to me because it wasn't about a traditional hot rod. I respect the H.A.M.B. and the culture they're trying to preserve but just because the members cars are set in a particular spot in time, I doubt that their technical savvy is limited to "traditional" thinking.

 

[malibu101]

Yep. Place it so it can get as hot as possible.

 

[Brian_B_]

I am a member over there (have been for a long time). Its great info, but my truck does not fit their mold. LOL

I rarely post anything over there anymore. Try hotrodders.com

 

[tcianci]

I am a member over there (have been for a long time). Its great info, but my truck does not fit their mold. LOL

I rarely post anything over there anymore. Try hotrodders.com

I guess I posted on my getting deleted over there because I was really taken aback by what happened. I love the H.A.M.B. and have been a member for years. I didn't mean to shatter their fragile little world by asking a technical question.

NIce Effie BTW Brian

 

[Brian_B_]

I posted some until I found out I can't really talk about my truck over there. And mine is stock! LOL

Oh well..every forum has their good and bad. I do like to read over there a lot though.

I get a lot more help from hotrodders and ford specific forums with mine.

 

[rsanter]

Do not put it in the crossover tube
It needs to see good heat and exhaust flow

Bob

 

[Rodhotz]

9" from the last cylinder is what they call for, if it is set up for 2 i would run both as it will give the ecu a better read on the motor side for side. Also you never want it after a collector where an exhaust leak could skew the reading.

 

[theoldwizard1]

If I may stick my head in, place it in the crossover

Wrong, unless you are using a heated EGO.

Place it so it can get as hot as possible.

Right.


In reality in depends on the original hardware/software. Given the "vintage" of TBI (probably over 10+ years old) I'm guessing the software is "assuming" the EGO is in the exhaust manifold. If you are running headers, put it in the collector, but you will need a heated EGO and additional wiring (fuse, relay, etc.) to turn it on and off.

If the EGO is not up to temp it will not read correctly and the software will stay in open loop which will not perform as good as it should. Sort of a "limp home" mode.

(I have over 31 years of EFI system/software design experience.)

 

[Zeke]

I posted this question over on the H.A.M.B. too but it was thrown off quicker than a cheap prom dress. I got my *** handed to me because it wasn't about a traditional hot rod. I respect the H.A.M.B. and the culture they're trying to preserve but just because the members cars are set in a particular spot in time, I doubt that their technical savvy is limited to "traditional" thinking.

Well, if that's your truck in your avatar and it's not considered a hot rod, I don't know what is. I sure don't need to go over there. All I have is a '44 GPW (jeep) with a 327 (cam and HEI) in it. I guess because it's 4WD, I need to stay away.

 

[Carguy99]

I do agree "In reality in depends on the original hardware/software. Given the "vintage" of TBI"
If you put in one side it will read that side and not the other (as well).
many older cars ran unheated OS's very far from the engine look at some of the early Fords some of those are 8 feet from the engine. so not a big deal.
I have done this type of swap several times. On a single O2s B1S1 only, it needs to see both sides. just my two cents worth.

 

[crewchief888]

i did an engine swap in my s-10 blazer, swapped a TBI 4.3 for the original blown 2.8.

headman headers, duals, 2" pipe and thrush turbo mufflers.

i took some measurements from other 4.3 powered blazers and astro vans, and put the O2 sensor as close to that position as i could.

downstream of the rh collector.

not reading the drivers side exhaust at all. truck runs fine, no need for emissions tests, it's an off road only truck.

 

[tcianci]

i did an engine swap in my s-10 blazer, swapped a TBI 4.3 for the original blown 2.8.

headman headers, duals, 2" pipe and thrush turbo mufflers.

i took some measurements from other 4.3 powered blazers and astro vans, and put the O2 sensor as close to that position as i could.

downstream of the rh collector.

not reading the drivers side exhaust at all. truck runs fine, no need for emissions tests, it's an off road only truck.

Thanks for the additional information. I'm using the stock exhaust manifolds from the Astro van and the system is also 2" with a pair of Flowmasters out back. The engine pipe on the drivers side is still loose so after I drop the ingine in, I can pick a location for the bung and weld it in.