I guess my O2 sensor gave up?
 

After 2+ years.

This is on my innovate LC-1. The gauge seems to alternate between pegged full lean or pegged full rich. Every so often it gets 'confused' and the needle sweeps back and forth across nearly the entire range.

Is this normal failure mode for a sensor gone bad?

I think when an O2 sensor gives up the Ghost, the system automatically goes into a default rich mode, so I doubt it would cause such a swing back and forth.

You may have something as simple as a loose connection somewhere, such as a ground wire to the gauge.

Good luck!

My 02 sensor started acting similarly on my LC1 a few months back.

I plan to take it out this winter and inspect it.

It tended to go to lean at start and alos show the 02 diag signal on the gauge, and then bounce around and eventually seemed to end up at the 14.5 or so I expect at idle.

Not sure if the 02 placement just past the turbo is too hot a location and is burning the sensor out or if I have an air leak somewhere or some A/F issue.

But thought I'd share a data point that after 2 seasons with my 02 sensor located just past my turbo it started acting similarly.

Yep, I'd buy in to that logic. If the AFR's were fluctuating as much as stated (pegging either end), then I would think the engine may tell you the same buy running weird.

My vote: Get rid of the O2 and tune to run open loop. Never look back....

I think Jacob is referring to the 02 sensor for the LC1, not the 02 sensor for the engine mgmt. It may be the 02 sensor for the engine is fine and the engine is running fine, however the 02 sensor used by the LC1 ( a separate sensor) is indicating a swing on the AFR gauge.

In my case the engine is running fine and the LC1/AFR gauge is getting the swings at cold start. The Innovate manual recommends placing their 02 sensor away from turbo heat and also using a heat sink if required to manage temps. Excess heat can burn it out.

The '79 is open loop from the factory (and non-catalyst:D). The o2 sensor is for wide-band afr monitoring only and has nothing to do with fueling.

Car runs just fine, only my AFR guage is suddenly useless. I will check for stupid loose wires, but wanted to hear what others have experienced when the sensor is failing. I've heard that these sensors don't last very long 3" from the turbine outlet, and mine has lived there just over 2 years (including 2 trackdays).

Jeeze....somebody kick me in the head. Of course it's the sensor for the LM1, not the engine! Got a nasty case of the flu, if that's a valid excuse.

Jacob,
Mine started doing the same thing a few months ago.
I checked all the wiring and couldn't find any obvious problems.
Eventually, almost as a last resort, I did a recalibration and that fixed it.

Mine used to flash ERROR 2, ERROR 9 or similar when I got on it pulling out of the pits hard. Only a new O2 sensor would fix it.

BTW: Where's a good place to get a new one, as it's a VW part? Any place on-line?

those symtoms have happened to my lc-1 and g3 gauge in the past.. and doing a complete reboot with the O2 sensor umplugged from the lc-1 harness for a minute to erase the corrupted o2 sensor heater calibration and free air sensor calibration and then start over from the beginning like the instructions say and do the o2 sensor heater calibration while watching the timed seconds on a timer or watch and then do the timed o2 sensor free air calibration.. these are two seperate steps that have be done correctly.

after that no more weird complete back and forth sweeps of the afr needle readings stuff and it works very well and steady again.

my first stepper motor analog g3 gauge was no good and the needle would seize in place at times.. innovate sent me a free replacement that works perfect so their customer service does try to help.

i got a new oem one from amazon for about $60.
Bosch 17014 Oxygen Sensor .

now amazon reminds me once or twice a year when they are on sale.. here's a copy and paste from one of their emails.

Amazon.com has new recommendations for you based on items you purchased or told us you own.

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That's interesting, Jim. Mine did the same thing so I took it apart and found that the mounting nuts that secure the faceplate studs were loose. Sounds like whoever manufactures the G3's for Innovate needs to tighten up their act.

Thanks Jim. I want to say I paid $92 at the VW dealer last time, but wanted it quick.