Hey guys,

I wired the analog output of my AEM UEGO (30-4110) successfully to pin 73 of the ECU (ADC signal for rear o2) and properly disabled my rear o2 heater circuit (using tephramod v7 and also set up the proper sim patch).

I am trying to run through all of the numbers and sanity check myself, yet something is not making sense to me and hopefully someone can clarify. In EvoScan I am using an eval formula which works great! The number when data logging is very very close to the number on the physical gauge. For example, when I shut off the car the reading was exactly at 16.4 AFR and so I wanted to calculate the voltage on the pin 73 at that very moment to see if I can set up my EcuFlash AFR safety voltage properly. Using the EvoScan eval formula which I am using, finding the value of x gave me 171.224 as the ADC reading (in decimal, not hex). Now since I know that pin 73 is the input of a 10 bit resolution ADC with 5V reference, you can calculate the voltage based on that information. When using V=(ADC_reading * 5V)/1024 I only get 0.836 V which does not make sense. Based on page 7 of the AEM user manual (https://static.summitracing.com/glob...vm-30-4110.pdf) I should be seeing about 3.12 V for the ADC reading of 171.224.

Am I doing something wrong and not realizing it?

 

Oh, is it only an 8 bit ADC? I think I just answered my own question if so. The numbers seem to line up now