Today was the first time I got WinALDL working with my car, I just got it up and running again. My ECM had a bad connection with the PROM socket, and another ECM with my PROM seems to have fixed the problem. The car is running good, although with a slightly rough idle, and running a little rich, the exhaust smells of gas. My BLM reading was sitting at 158 idling, at full operating temp, and the ECM threw an "O2 sensor lean" code. I'm 99% sure that means the O2 sensor needs replacing, but could it be anything else? From what I understand, the BLM should be at 128, if it's above then the ECM is adding fuel, and if it's below the ECM is pulling fuel. Is this correct? Also, according to WinALDL, my CTS was at 240F, when the gauge only showed about 210F. Is this a bad CTS, or could there really be a 30 degree difference between the 2 sensors?

 

Ward

With BLM values above 128 ECM is adding fuel to compensate for a lean condition at a particular load and RPM and when below 128 it is taking out fuel to correct for a rich condition. Under normal conditions BLM values almost always fluctuate about 128 give or take few counts once ECM learns your engine. Lean condition in CL operation - Code 44 - is set when the O2 sensor signal voltage remains below .3 volts for 50 seconds. If you have WinALDL or a scanner take a look at O2 readings. Also, you can verify O2 Sensor by measuring its output voltage with a DVM.
240F IMHO is a bit high for CTS at idle - the dash sensor is positioned in a different location from CTS (which is near thermostat). Take a look at CTS connector and sensor. Sensor do go bad with age.

//RF