Long story short I replaced the upstream o2 sensors (2). B1 s1 no voltage at all, b2 s1 works fine at idle (.995-1.015) but when I push down accelerator the voltage drops to 0.000. Both s2's are working fine. I suspect that b1 s1 has a short in the wiring? But is it possible this is a computer issue? Thanks

 

I'll vote for wiring and maybe a ground issue.

 

I rewired the the whole o2 loom with a salvaged harness and now have started getting normal voltage readings. Although at times the readings seem a bit low on upstream, is this due to the ecu having to find new parameters?