1998 Conti 02 sensor locations

[chuckneste]

Hello All,

How many O2 sensors are there upstream from the cat and does the obdII read more than one O2 sensor. I do see one o2 sensor before the cat and one near the y pipe near the oil filter.
Chuck
1988 Conti 100K

[chuckneste]

hello again,

Since I had no answers, I came across this document

http://www.motorcraftservice.com/vdi...f/obdsm962.pdf

Some V-engines have exhaust banks that combine into a single underbody catalyst. These systems are
referred to as Y-pipe systems. They use only one rear HO2S sensor along with the two front, fuel-control HO2S
sensors. Y-pipe system uses three sensors in all. For Y-pipe systems, the two front HO2S sensor signals are
combined by the software to infer what the HO2S signal would have been in front of the monitored catalyst. The

inferred front HO2S signal and the actual single, rear HO2S signal is then used to calculate the switch ratio.