I've just got my techedge WB out and was testing on my stock 99 civic with the sensor clamped to the tailpipe.

WOT has the display pinning out at 10.5 (wont read any lower)
Closed loop has the A/F at about 12.5
Idle is 13.5

Do these numbers sound right for a bone stock car??

 

Sounds abit rich to me.

Close loop and idle should vary around at/close to 14.7

 

I wonder if having the sensor clamped to the tail pipe would affect the #'s?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DIRep &raquo;</TD></TR><TR><TD CLASS="quote">I wonder if having the sensor clamped to the tail pipe would affect the #'s?</TD></TR></TABLE>

Me too

 

Yep. Mount it before the CAT and you'll get more accurate numbers.

I believe it has something to do with the exhaust gases not being hot enough at the muffler tip.

 

I'm also measuring after the cat, which I'm not sure how badly will affect the numbers. I just rigged this up to verify the sensor was responding.. which it is.

Do you think its possible that a stock car will have A/Fs around 10 at WOT?
The closed loop #s are somewhat where they should be (or so it would appear)

 

Go to a shop and have the proper O2 bung welded on before the cat, you will see huge differences in readings.

 

the unit will be used to tune a friends turbo civic, and it will be installed properly when we do that. I just had it on my stock civic to verify its functionality.


I noticed that when going WOT, it will go off scale rich, then recover to about 12.0 after a few seconds (all the while at WOT)

so either the A/F overshoots abit from switching from closed to open loop, or the sensor itself overreacts with the change.