I've noticed that my BLM value doesn't agree with my O2 sensor. My best example is a BLM coarse value of 160, fine at 128, when the O2 sensor is mostly reading from 700 to 800 mV with a few brief dips down to 300 mV or so. This is done at idle, CTS reporting 180*, and engine run time is about 100 seconds. It was warmed up already. (160 means lean right?)

Any ideas about what is going on? Am I completely missing something obvious to everyine else?

 

Yes blm of 160 is lean, and maxed out. You need to mke sure it's in closed loop and then look at the O2 sensor-it should then swing back and forth rapidly above and below 450mv. If the O2 sensor is not working correctly you'll never get it tuned!

 

OK, I see what you are saying. The O2 sensor is about a year old, but I had to take it out once and used Neverseize to put it back in. From what I've heard, that shouldn't have damaged the sensor. The computer is in closed loop and I do see the O2 sensor swinging back and forth, but it does stay low sometimes.


Let me ask it another way. How does the computer calculate the BLM value? I ask because I fixed a vacume leak and now the coarse and fine values max out at 160. I can't figure out why. Although the MAF is ported I'm trying to get the tables to work right but nothing seems to help.