Help!!!! I've tried just about everything.new o2 sensor, new ecm I burn proms and have changed settings to make o2s enable sooner but made no difference.The scanner reads that it is crossing over but o2 voltage stays between 458 and 453 only affected when rpm change. And to add to this tps reading is'nt constant. I've lowered the threshold for maf error to 30 thinking it might be it but still no code but ran better and idled higher. any ideas????

 

test you coolant temp sensor.

 

you might be running way lean or rich.

 

cts registers on scanner correctly. New computer installed and now have code 45.(too rich) even though new o2 barely moves. Of the possible causes of 45(code) my tps voltage keeps changing fro m 48 to 7x. Would this influence not going into closed loop.????

 

i re-read your first post and you said o2 was only going between 453mv-458mv, right? if so its not switching from rich to lean, cause anything over 450mv should be rich & below 450mv should be lean. but its not going into closed loop so the o2 wont switch. 3 things are needed for closed loop, temp, time, and a switching o2. im not sure about how much time has to elapse, someone else might know, temp should be ok since you said it checked out ok, what does it read, just curious. has to be something with the o2 sensor. i will try to do some more research for you, right now i just dont know.

 

oh just thought of something else, are you using a different thermostat than stock? cause that might cause it too.

 

CTS has gotten to 158 and temp gauge about the same. new ecm . thanks for the response .Still no closed loop. Can't go racing like this.... help!!!