I realise the Lambda sensor or wideband is the major tuning tool when setting up tuning, but what part does a wideband like the AEM UEGO or PLX Devices units play in real time tuning of the AEM ECU?

I'm aware that the OEM ECU goes into a closed loop condition under certain steady parameters and begins using feedback from the narrowband 02 sensor to trim fuel tables. Does the AEM have a closed loop mode? How is it enabled and how much effect does it have on tuning?

I have a tuned AEM but later installed the AEM UEGO. Whereas it's signal is visible by the AEM ECU I don't think it currently plays any part in the tuning process. But as I will be retuning shortly for the turbo set up I would like to understand how best to utilise the wideband.

 

Using the PRO software, go to Fuel, O2 sensor feedback. There is a table in which you enter the taget O2 values for load and RPM. Under options there is a check box for O2 FB (feedback) Control. If there is a check the EMS adjusts fuel to achieve the Target values entered in that table. One thing to watch out for it to make sure that the EMS is seeing the same AF readings that the UEGO is dislaying (if you have the gauge). In the Setup, senors, O2 there are wizards for two O2 sensors. When I tried to use the wizard my AF readings where off between the gauge and the EMS. I had to manualy adjust the voltage level differant to make it read accurately.

There is more to it than that I'm sure, but that is my understanding of how it works, and the way mine is set-up. Check the AEM forums, that is where I got most of the information I have on the EMS.

 

double check the Wideband is displaying the same AF as the EMS is seeing.

I've been working on a car that drop a full AF point when the cooling fan is on. After rewiring the fan, the previous correction table was screwed.

Part throttle the car would go SUPER lean with the 02 feedback enabled.