I have a 99 si boosted with an AEM EMS and AEM wideband. My question is do I need the stock O2s. I am assuming yes, but am not sure. Do I possibly only need the front O2 and can use a emulator for the rear (I have no cat). Or can I just tell the AEM to ignore the rear O2 and just read the front. The wideband is not feeding the AEM either...all it feeds is the air/fuel meter. The car is obd2 and the AEM is the obd2 EMS.

Pretty basic stuff but I don't have any experience with this EMS and turbo setup. Thanks for the help.

 

aem ems DOES NOT use the factory o2's at all, might as well remove them and plug them. it DOES need a wideband o2 though, which is where your uego gauge comes in, put that BEFORE any cats, and that wires into the ems. i recommend you read the manual!