im going to install a aem uego, is it necessary to have the primary o2/afr sensor installed also or can i just replace it w/ the aem uego sensor and use the data input wire in conjunction w/ the aem fic for proper afr calibrations?

 

do you want your car to constantly have a check engine light? if the answer is no then dont do it. one of the perameters of the ecu is to check voltage to the heater in the o2, if its not there it will throw a code. youll notice that the primary o2 sensor has 4 wires, two are for the o2 heater.

 

what the f is an o2 heater?

 

All modern O2 sensors have an integrated 12V resistive heater circuit to enable them to reach their operating temp earlier. O2 sensors only function accurately within specific temp ranges.

To the OP, it's a shame that we have to install a second wideband O2 sensor for a AFR gauge but so far no one has bothered to make an AFR gauge that uses the oem wideband sensor. I looked hard for one and found nothing. The closest thing is OBD2 scan software that can read AFR from the oem ecu but unless you're running a car PC and are fluent at reading lambda, you're stuck installing a duplicate wideband O2 sensor if you want a AFR gauge.

 

Blow-torch, bung, mig welder, done.

 

word

anyone tell you you sound like a dictionary...lol

 

Not until now.

 

 

Hey funny man, when you're done laughing, can you answer an O2 related question for me?

How close is the FIC's aux gauge calibration for the digital UEGO? I finally hooked mine up today and the FIC reads slightly leaner than the gauge. E.g., when the oem denso reads 14.7, my UEGO reads 15.0 and the FIC reads 15.3. My denso is in the DP and my UEGO sensor is in the s-pipe. I have a slight exhaust leak so I can see why the uego reads a bit leaner but the FIC should match the gauge since it's reading the same sensor.

I lowered the 5v calibration to 19:1 and calculated the rest of the AFR cells between 10-19. That brought the FIC readings very close to the gauge at lambda. Is this common?

 

iv noticed the same thing. not sure why this is exactly but there are a few variables to consider, sensor cal off from factory, also it could be the fact that the chart thats in the instructions are just generic, also consider the gauge wire used to make the connection and the connectors used, in anycase iv never seen the chart exactly match what the gauge says. so iv always had to calibrate the fic with the wideband.

 

I'm not too concerned about it but I was curious if this was a common issue with a common fix. According to AEM they calibrate each Bosch sensor to output a specific voltage at a specific AFR and it should be a no-brainer to calibrate the gauge and FIC to read the same... but we are talking about AEM.

Once I get my exhaust leak fixed my UEGO should match the oem denso more closely and I'll re-calibrate the FIC aux gauge to match them. If I can them get within .2 afr, I can easily live with that.

BTW, what do you recommend for a target AFR at 6psi on 93 pump? I'm currently tuning for 11:1 and pulling 1* timing per 1.5psi boost to be safe.

 

you can deff get them within .2 of each other and maybe closer.

this is just me (everyone has their on views on this) but id tune for 11.5-11.7, you could get away with 12:1 but im sure youd like a safety margin. at 6psi you could get away with not taking anytimeing out but to keep a little margin in ther id suggest 1-2degree at 6psi. so you could tune for 11.5 afr and 2 degree retard @ 6psi.

 

Perhaps it has to do with the fact that the OEM denso is a WRAF (wide range air fuel)sensor which reads a bias voltage of 3.3v It's probably just a calibration and resistance value between the two sensors

 

Thanks Crush. I know 11:1 is kind of rich but I read that a lot of factory turbo cars run 10:1. Like them, I'm tuning more for safety than max hp. Because of my AT, I don't want to make more than 240whp and I'd settle for less. There's another XB2 with a similar setup to mine who made 300+ at 8psi so I'm optimistic that I should reach my whp goal at 6psi. I was planning to maybe add some timing back after I get the AFR dialed in and log my EGTs. Does this seem reasonable to you?