Howdy kind folks. I’ve been dealing with a serious wideband problem for longer than I like to admit. Maybe one of you electrical gurus can give me some advice. So I have an aem uego wideband and an mspnp2 on a 95 chassis. I have been having a signal issue to my ecu from the wideband.

So what has been happening is that the gauge when connected to the pin for o2 signal on the options port is not putting out a signal from the white wire (0-5v) wire. When I disconnect the wire from the ecu and key on to acc the white wire from the gauge outputs a seemingly correct voltage about 2.5ish don’t quote me on that for 14.5 and 5v for full lean. So this is where my conundrum is.

How I have the gauge wired: I have a power wire coming from the battery to a relay that is activated by accessory power when keyed on. Gives a good solid current through the gauge. I then have had it grounded to I’m not certain which ground on the options plug for the ecu and the ground wires underneath the master cylinder and a handful of other places and can’t seem to get the Thing to send some current into the ecu.

So my question is what is the best grounding point for a wideband. I am going to double check my options pin and make sure Ive got it going to the proper pin on the ecu. However in the past when I swapped o2 sensors it would actually output a signal to the ecu for a short period of time maybe half an hour then stop.