can cracked exhaust mani.= bad O2 voltage?

[brownfinger]

Even though you can smell that the car is running rich, datalogger says all my fuel trims are maxed out, all of the time. The O2 wasn't giving a reading at all, unless I really got on it. Then as soon as I'd start driving normal, the reading would go away again. I assumed the heater circuit was bad and replaced the sensor with a slightly used one I had around. The sensor output now looks more like what I'd expect to see, except at idle. Still little/no signal. This is causing the st trim to stay maxed out most of the time. Could my cracked exhaust manifold be throwing off the O2 content in the exhaust gas enough to cause this? I was under the impression that the O2 feedback is supposed to be functioning at idle.
Also, no matter how hard I get on it, there is little to no action from the accel. enrichment. I'm new to the data logging, but I'm pretty sure that something here isn't right. Well, if you drove my car you'd know something isn't right, but I don't know what "normal" values are for about half the datalogger parameters.
Any help?

 

[ryanman]

Yes, the crack will affect it.