Jumpy O2 volts at idle...

[timothydog]

Hey gang,

Trying to tune up my 86 TType. Tonight I replaced my PCV valve and set my idle per the instructions at gnttype.org (by the way... does anyone else find 500 +/- 50 rpm a little too LOW? stumblin' bumblin'!). So the car is purring a little better while at a stop around 675-700.

But I notice one thing on the OTC. My O2 Volts are jumpy as a mofo. They range from .20 to about .80 at idle. The car is constantly switching between lean and rich. What could be the problem? The O2 sensor is less than a week old. When I hold the rpms up a little the volts even off pretty well.

I have a brand new Walbro 307, stock injectors, brand new rebuilt stock turbo. The EGR valve seems to be working OK. I push it up while running and the car stumbles but then returns to normal immediately.

Any clues?

TIA
Tim S.

 

[Spoolinup]

Your ok on the jumpy 02, you said it yourself, its going from lean to rich.

Watch the blm for the idle tuning, the 02 is only a reference point at wot. It is not accurate for tuning at idle.

And I have my idle set in the chip for 800 due to my cam.

 

[TurboDave]

Our O2 sensors are the "switching" type sensors, and as such, while in closed loop operation, the O2 voltages will be all over the place!!! It's normal. The only time they stabalize is during open loop operation or when in "power enrichment"(accelerating smartly).

 

[timothydog]

Thanks dudes,
That is one less thing I have to worry myself about..
Now.. on to the other things.