Hey guys! New member here, this is my first post.

Just installed a MSPnP3pro in my 2004, and an X-Series AEM UEGO. Started up perfectly on the base map, and the WB guage is reading accurate AFRs.
Strangely, TS is picking up a 4.99 V signal almost constantly. When the car really richens up, it drops to lower readings, but stoich on the gauge maxes out the reading in Tunerstudio.
I don't currently have a multimeter to test what the true output is, but I will borrow one soon to figure out whats going on. My 0-5v output from the WB is connected to the blue wire (signal input)
on the stock O2 plug. Changing the ground location doesn't help. I can think of many ways it could read a lower voltage than true, but I'm stumped on why it's reading so high.
Any input would be great appreciated, thanks in advance

 

Change the settings in your megasquirt to match the output it should be seeing from the AEM? It is probably scaled incorrectly. Or your AEM or its signal is screwed up.

 

Scaling the wideband doesnt work.. the highest its reading is still a 5V output. Somewhere between the WB controller and the MS the signal is getting disrupted. Does the signal need to go directly to the MS or should it normally work with it wired into the stock harness?

 

Both should work the same

 

I always wire directly to eliminate the exact variables you seem to be experiencing

 

Connect the white wire from the X-Series UEGO to the MS3's analog input, and also connect the brown wire from the UEGO to a sensor ground on the MS3.

 

There's a little ****/switch on the back of the Wideband. Is that in the correct orientation?

 

UPDATE: I checked the AEMs outputs with a miltimeter.. the white 0-5V wire was reading around 5.2V @ 12.0 : 1... but the brown NEGATIVE 0-5V was reading POSITIVE voltage, and perfectly accurate. Lol it appears the output wiring harness was assembled incorrectly. Anyone seen this before? TS now displays perfect AFRs