Uhhh crap?

[equate975]

I hooked up an AFR guage to see what my mixture was. I started it up and it was dead stoich. Started driving a bit and it wouldnt fluxuate, then it got leaner, leaner, and leaner. Now the bottom LED struggles to light up. All my connections are good.

Either I have a bad o2, or my AFR is off the scale for being lean.

[EtaSport]

Wide or narrow band gauge? If you are going from a tuning standpoint, you will never get an accurate reading with narrowband. Its just a light show. If its wideband, you might want to look into it, check o2 voltage output, and then see if you can turn up the fuel pressure or increase injector pulse width.

[equate975]

Narrow, but it shows a ball park. I just wanted to see if its running very rich or lean.

Basically this is what it does

Car on:
Stoich for a while (even with revs or driving it wont change)
Gets to the lower end of stoich
High lean
very lean
Guage quits because its too lean.

All this happenes in about 1-2 min. If I shut the car off wait a bit then turn it back on, same thing happens over and over.

EDIT:

and I dont have anything to play with the fuel pressure ot change the injector pulse width.

[MrK]

I have a narrow band gauge, and it'll always show stoich on startup while the o2 preps to function. In a minute or two, the o2 should start oscillating between rich and lean, usually about one or two marks rich, and then swinging to one or two marks lean, and repeat. If your gauge isn't doing that, then:

1. Your o2 sensor is crapped out.
2. Your gauge is not connected properly, or it's faulty.

Hope that helped.

[equate975]

Ok yeah, I just wanted to make sure that either my o2 was dead or my engine really was running that lean. Although if it really was I would guess it would have blown my head by now :)

I will replace the o2 I guess.

Thanks for the help

[EtaSport]

If you have access to a digital multimeter hook it up to the signal wire and a good ground. Just check for a reference voltage. You should see at least .4 volts, but it may jump from .3 to .7 roughly. It you rev the engine it should change slightly. Thats how I found out mine went bad. Also make sure the engine is warm.

[equate975]

Is there a way to test it out of the car? I have an extra o2 laying around but I dont know if its good. I would like to test it before I screw around installing it just to find out its bad

[MrK]

I'm assuming it's an o2 with a heater core. If it is, you can wire it up to the gauge and a 12 volt source, turn on the car, and stick it in the end of the exhaust pipe. It should give SOME indication of oscillating in a minute or two.

EDIT!: It won't oscillate, because it won't be connected to the ECU (DUH), but it shouldn't read full lean at least.

[equate975]

Yeah its a 4 wire, Ill try that thanks

[EtaSport]

the o2 makes it own voltage. but wont start cycling until its around 600 degrees. You may be able to do a resistance test.