O2 Sensors

["Graydon D. Stuckey" <graydon@apollo.gmi.edu>]

On Sun, 31 Dec 1995 PDQSHIP@aol.com wrote:

> My guess is it is the O2 itself.......  But, an O2 sensor is a 40k part max,

Bosch guarantees their O2 sensors for 60K miles.

> prolly the most heat next to the Cat chamber, and this could help warmup
> (altho with three wire hookup, I'm not convinced this is a necessity) and

I have used heated and non heated O2 sensors on the RX7.  Without the 
heater, it would cool down when idling at a stop light!  With the heater, 
it was reading OK by time I was 100 yards out of the driveway (about 45 
seconds.)

> The electronic ignition systems are more sensitive to O2 input than say a CIS
> sytem, cuz on a CIS the idle baseline is set lean, then the O2 will add fuel,
> which is not the cas with the electronic systems, which means that if the O2
> is slow (which is what happens as it goes "bad"), the emissions will be "out"
> almost immediately........

	Exactly what I have found on the Quattro.  I have an O2 sensor 
output monitor, and have found that when the Quattro has settled into a 
long smooth idle, all the LEDs go out, indicating a very lean idle.

	I have also found a very bad part throttle lean spot at around 
3500 RPM.  It isn't there under full throttle, only part throttle.  Very 
annoying.  Makes me want to switch over to fully electronic injection 
really bad.  I wish I could find the time.

Later,								
Graydon D. Stuckey								
graydon@apollo.gmi.edu								
'86 Audi 5000 CS Turbo Quattro, GDS Racing Stage II				
'85 Mazda RX7 GS 12A-leaning-towards-a-13B-soon