After 200 miles on my new motor, the check engine light came on while driving on the highway. The scanmaster showed a code 13 which is a bad o2 sensor. It was showing that the left o2 was holding pretty steady at around 400 mv while the right seemed to be working ok. I also noticed that my left BLM was showing 160 while cruising but dropped back down to 131 at idle. Is there a possible relation between the 2 problems or do I need to attack each one separately?
I have already checked for vacuum leaks that would cause my BLMs to be as high as they are. None found. Are there any suggestions as to what I should be looking for to fix these problems? Thanks for any help you guys can give.

 

This question belongs on "LT1 Engine Tech" and will be moved there.

DTC 13 = Bank 1 (left) Heated Oxygen Sensor (HO2S) Circuit (open circuit)

Don't just jump to the generic conclusion "which is a bad o2 sensor".... because that is not what the code says.... read it carefully. The heater circuit in the drivers side O2 sensor is not working.

When an O2 sensor doesn't heat up, it doens't develop the voltage response to O2 content. It stays right at 450mV, which is the bias voltage the PCM is applying. You need to figure out why the sensor heater isn't working?

Do you have headers? (A list of mods is really critical to solving these problems, if you aren't going to include them in your signature, at least list them in your question, so people can know what the possible problems are). Do you have sensor extensions? Did you check continuity of the extension to insure is was working? Might be a faulty extension. Might be a damaged heater in the O2 sensor. After you check to insure you are getting +12V from the extension heater wires, swap the O2 sensors side-to-side. If the problem follows the sensor, its a sensor problem. If the problem stays on the drivers side, its a power supply/wiring problem.

Yes.... O2 sensors are the prime determinant of the BLM's. The PCM looks at the O2 sensor to see if the "standard" fuel injector pulse width calculations are providing the proper amount of fuel. If the O2 sensor is not reporting the correct 14.7:1 stoichiometric A/F ratio, the PCM first adjusts the short term fuel corrections (INT's) to correct the problem. If the PCM finds that over a long period of time, it is always making the same correction with the INT, it move the long term fuel correction (BLM) to provide that amount of correction on a constant basis. Bottom line, the PCM looks at the O2 sensors to set the BLM's, and if the O2 sensor is sending "bad" data, the BLM's will be wrong.

I would check the O2 sensors and the harnesses, to insure the harnesses represent a quality wiring product, they are properly connected to the harness and sensor, and that the sensors were not damaged or contaminated when you installed them. Then see what happens to the BLM's.