weird o'2 readings

[tom j]

installed new motor this weekend , but I am getting low o'2 readings from DS 400 to 500 range at idle blm's are 128 and iac and tps reading are fine, i dont seem to have a vacume leak that i could tell and if i did wouldn't the blm # be high, does this seam to be a bad o2, there are no trouble codes, han't drove car yet do to radiator problem, what do you guy's think?

 

[NM Tom]

Check the ground strap behind passenger head. Mine was loose and it caused o2's to read very low all the time even though car ran fine. The o2 sensor ground is one of those wires. After tightening, all numbers fell right in line. Good luck!

 

[Topjimmy]

Sounds familiar Toms, I had the same problem after freshening the engine, scan tool numbers were all fine except low 02's. Engine would barely run as the ground bolt loosened on the firewall. I added another universal ground strap from NAPA and ran it from the intake to the firewall along with the existing strap. Problem solved.

Good Luck - Jimmy

 

[tom j]

you guy's nailed it, found a broken ground wire on the grounding stud, Thanks