02 readings all over the place, super-crappy mileage

[snowcat]

In this post:

http://bbs.legacycentral.org/viewtopic.php?t=552

Morgie says "if you have a volt meter you can test the O2 sensor wire while driving. At closed loop your readings will fluctuate between .01 and 1 volt. When in open loop, your reading should stay ALOT steadier . . . maybe within .08 and 1 volt." (in reference to n/a engine.)


- I have vrg3's scantool, and I NEVER get a steady reading b/w .08 and 1 v, nor do I ever get steady-ish readings around stoichio, .45v. I have a 94 ej22t turbo wagon and I'm always all over the board. Change 02 sens several times, including once when lost wire connections and killed sensor. Coolant temp sensor replaced w/j.y. salvage, but tested ok as far as resistance range.

I get super crappy gas mileage, which has just gotten worse, possibly after using berryman's b12 additive. A chemist told me it was the shit, now I'm starting to wonder.

Anyway, there's a good poss. that my cat is toast after losing my 02 sensor, but my big question is wtf is going on w/my 02 readings? Is my car in limp home strategy? Also, my car keeps throwing a 51 neutral sensor switch code. Would that come into the mix as far as closed/open loop and crappy mileage?

Any help would be appreciated!

[Legacy777]

Your O2 readings will always fluctuate. Looking at a narrow band O2 sensor output really won't tell you anything.

If you have a lot of miles on the O2 sensor it probably wouldn't be a bad idea to replace it.

[n2x4]

Check your knock sensor as well - if it's cracked it will be hurting performance.