BB512i & Emmission Control Devices

Adding really functional O2 sensors to a BBi with K-Jet injection would be quite a project. You'd have to "convert" each K-Jet system either by:

1. adding a frequency valve, the plumbing, plus whatever else is required, etc. to make it a K-Jet with Lambda system (like the later 308QV), or

2. replace both whole K-Jet systems with KE-Jet with Lambda systems from something like a TR or 412(?).

You are correct that connecting the outputs from the O2 sensors is not useful nor useable, but if they are the 3-wire kind of O2 sensors then the internal heaters could share some common connections -- are they the cheaper single-wire only O2 sensors or the 3-wire O2 sensors with the internal heater? It doesn't hurt to have O2 sensors mounted in the exhaust stream on a K-Jet system -- you can always manually measure the O2 sensor outputs with a multi-meter or oscilloscope as a another tool for guesstimating the A/F ratio in each bank under various conditions.

 

My former 1986 TR with K-Jetronic had 02 sensors that appeared to function. If I recall correctly the sensors were wired to a “black” box located under the driver’s(?) seat, installed by the conversion company. Again if I recall correctly the box was then wired to the cold start valve(?). This is 4 years ago so I could be completely wrong. The reason I believe they functioned is attending a local auto show at the Crane Estate I was parked in a converted cow pasture. Upon leaving a low cut bush disconnected 1 of the 02 wires. The TR ran like crap, wet fouled a couple of plugs on the side disconnected. Repaired the 02 sensor, installed new plugs and the TR ran fine. Also the TR passed MA emissions testing 2 years with flying colors.
My beautiful Euro headers were also mangled at conversion. All the tubes were cut approximately 2” from the heads, welded into a stainless rectangular collector and then piped into a pair of K car cats. Not very efficient. Purchased a set of Euro TR headers from Butch Hooper and installed a set of hyper flow type cats. Great sound, better performance.

 

TRs came "stock" in three injection flavors:

K-Jet (without Lambda) -- early standard (same as your 512BBi)
KE-Jet (without Lambda) -- later standard
KE-Jet with Lambda -- all US & later CH

If you only have single-wire O2 sensors and they are connected together, it can't be functional. There aren't many places to add extra electronics unnoticed, but you might have a look under your seats per John's description.

I'd classify the mods on John's ex-TR as a somewhat more crude version of #1 (remarkable their using the cold-start injectors as the fuel modulator). One safety feature of the stock "with Lambda" systems is that they can detect bogus or missing O2 signals and default into an open-loop mode so they don't dump extra fuel when things go wrong -- e.g., when John's TR O2 sensor went unplugged, the O2 voltage input to the "black box" drops to "0" so the electronics thinks "lean" and tries to add more fuel to bring up the voltage (but the input to the black box never changes since it's unplugged).

Side question for you both -- did they try to add any type of catalyst over-temp warning system?

 

My former Euro TR had no cat over-temp detection system. I do admit this did concern me. Know of more than 1 TR that suffered considerable damage due to cat fires.
As crude as the system was my TR ran better, stronger and less issues than most of the US spec TR’s I know. As I stated earlier, I do not know how much the system contributed to the cars operation during normal running.