Author Topic: AEM Wideband O2 sensor and the stock sensor (Read 4587 times)

asubimmer · « **on:** March 16, 2007, 05:41:49 PM »

I bought an AEM wideband O2 to replace my stock one and I was wondering if anyone knew what the 4 wires on the stock o2 sensor are. There is a black, grey and two whites. I'm puttin it on tonight so any help would be awsome

zerofreez · « **Reply #1 on:** March 16, 2007, 06:27:11 PM »

I really dont think that you will be able to hook a aem wideband up to your factory harness and expect it to work.

Wideband o2 sensors use a 5 volt signal and regular o2 sensors use a 1v signal, and thats just the start of the differences.

Dont know exactly what colors are for what but you have a power and ground wire for the o2 sensor heater, and a positive side and a negative side of the "battery" in the o2 sensor.

Here is the ETM.

For some reason the 318is ETM is missing from BMW's website so this is the one from the 318ic, should be exactly the same.

bmwman91 · « **Reply #2 on:** March 16, 2007, 06:37:39 PM »

You said this was from BMW's website? Where can I find wiring diagrams?

I think he is running a Megasquirt, so the WBO2 would be fine. I am running an LC-1 WB kit on mine and hooked most of it up to the OE harness. I DID jump some terminals on the O2 heater relay though, so I could get power in accessory mode rather than just while running.

If you end up wanting to do this, I can show you what I did. I pulled the relay out, and jumped 2 wires. I also had to wire in a dummy resistor across the relay actuator or whatever or else the Motronic tosses a fault out.

asubimmer · « **Reply #3 on:** March 16, 2007, 07:02:55 PM »

I am still wiring the harness for the MS and I don't want to put it in till I get back to boone. So for the moment the car is running on the stock ecu. I was under the impression that the wideband o2 sensor would still work fine w/ the stock ecu? So I guess I'm going to have to wait till sun when I get back to school and start installing MS to put on the wideband?

bmwman91 · « **Reply #4 on:** March 16, 2007, 07:54:57 PM »

Well, it depends. Does the WB setup have 2 analog outputs? The one I am running has 2 fully programmable outputs. One is configured to simulate a narrow-band sensor, the other is the WB range.

asubimmer · « **Reply #5 on:** March 16, 2007, 08:27:25 PM »

The AEM wideband has four wires wires...

red ..."connect to a 10-18 volt power source utilizing a 10A fuse"
black ..."connect to a clean ground"
white ... "connects to any auxiliary unit that accepts a 0-5 volt input"
blue ... "connects to a RS-232 com port for hyper-terminal data logging"

am I good to go or not?

zerofreez · « **Reply #6 on:** March 17, 2007, 07:34:48 AM »

No go.

You need a 0v to 1v signal for the dme