o2 sensor

[Goi Sihao]

hi,

i've built a 20 segment o2 meter using the lm3914 and have some problems
with it. i  hope this is the right place to ask.

anyways, i tested it on a 92 honda (1.6 sohc vtec) and encountered a
problem. the honda has a heated o2 sensor (4 wires), so i hooked up signal
wire to the signal input and signal ground to Ref(lo). Ref(hi) is set 1V
higher than Ref(lo). V+ is shorted to battery positive terminal and V- is
0v battery. i have a 4uf cap to smooth the power supply.

when i start the car, i can get a reading of the o2 sensor with a dmm, but
_not_ with the sensor! i do not read an voltage between Ref(lo) and
Ref(hi)!! the lower bank of led's r all lit but not the top bank.

i believe commercial o2 meters from the likes of cyberdyne have power
supply, power supply ground and the signal input only. however, i didnt not
get any likely readings when i connected Ref(lo) to power supply ground too!

i'd appreciate any help i can get here. thanks!

sihao