before i installed my header my air fuel ratio would stay right on the border of stoich and rich while crusing, after installing my header it is pinned at fully rich, i dont know if this is normal or not, just wondering how i can get it back to normal

thanks

-greg

 

what kind of a/f guage do yoy have? have you checked the spark plugs to make sure its running rich?

 

i have an autometer phantom gauge and it was working properly prior to installing the header, and no i havent checked the plugs

 

bump. i wanna know the answer for this too

 

bump

 

It sounds to me that when you installed your header, you either damaged you O2 sensor, did not plug it in, or have a bad connection.

O2 sensor output in mv FULL THROTTLE AIR/FUEL RATIO
.00 17.0:1
.10 17.0:1
.20 16.0:1
.30 15.5:1
.40 15.0:1
.50 14.7.0:1
.60 Dangerously Lean 14.6:1
.70 14.5:1
.85 Lean Max Power 14.2:1
.87 Max Power normally aspirated 13.5:1
.90 Max Power (Rich) (NOS,blower,Turbo) 13.2:1
.97 Very Rich 12.5:1


I have noticed that a/f meters, which are nothing more that voltmeters, will "saturate" if the input voltage is lost from that sensor.
What that means is, if the O2 sensor wire to the meter is not connected, the a/f meter will slowly start showing richer and richer until it is pegged.

Why?

Don't know.

here is a sugestion, something that I do on my vehicles. I use my multimeter and read the actual voltage coming off my o2 sensor while I am driving. It gives me an actual number, not a bar. I use O2 sensors to tune the carburator on my truck. It works pretty well.
But make sure it is hooked up and actually giving you a voltage first. I'm betting that is your problem. Any more questions, feel free to ask.
Ken

 

Are the numbers to the left representing the output voltage at the 02 sensor terminals?

 

This is just speculation but: The thermal reactor is designed to burn fuel that is ejected during the exhaust stroke. When you switch to the header, you don't get the burning effects, and therefore, the concentration of oxygen goes down, causing your AF ratio to look rich.

Is is a wideband gauge?

 

Yes, the number at left are millivolts. The post "edited" my spaces, and bunched it all together.

 

Last question: can this signal be read at idle?

 

It can be read whenever your O2 sensor is at least 500F. So, yes at idle, AFTER the car is warmed up.
If you have a multi meter, run 2 wires into your car, one spliced to the O2 sensing line, and a ground. Hook them to the meter, then drive around. The O2 "refreshes" its signal ever 500milliseconds(approximatly) so what you will see will be real time. Thats why it is good to do while driving. You get to see what your fuel injection is up to at different driving points.