Just curious does your 12A 1st Gen have an O^2 sensor in the exhaust manifold?

 

A O2 sensor is an intergal part of a fuel injected vehicle. 12A were carb's so no o2 sensor.

 

I haven't found mine in my 12A, but I'm still looking.........

 

i put one in mine so i could see if it ran like junk because it was too rich or too lean.

the earliest Bosch EFI systems and most mechanical FI systems (which were based on the GM/Rochester mechanical FI seen on some Chevys in the 50's and 60's) did not use O2 sensors, they were analog devices that happened to put out a fuel curve that seemed to work good enough

 

I'm still trying to find out why every 12 Valve, 3 barrel carb Honda I see has an o2 sensor. it confuses the hell outta me.

 

Some cars have a ecu controlled carb ie. electronic controlled GM, Mitsu,honda and Chrys.the 12-A's don't have one,so no O2 sensor.

 

Some Toyotas had a really cool system. They used a normal carb jetted for best power/safety at max load, which is a little too rich for best emissions. So they used an O2 sensor to give input to a computer which controlled a bypass valve - essentially a computer controlled vacuum leak! So under most conditions they could run at stoich, but under acceleration or heavy throttle the bypass valve would shut completely for a richer mixture under power. Neat.

The GM systems were total bastards - they had duty cycle solenoids on the air bleed circuits, and controlled mixture at the carb. Few people like to mess with them (and i'm not one of 'em!)