AEM wideband O2 readings on naturally aspirated
 

I just finished installing an AEM widband O2 and was wondering what should be my readings.

I am still using the factory ecu(DIYPNP MS soon to come), and I have completely removed the narrowband O2. I am currently reading 16.5-17 at cruise with 10% throttle and when I go 100% throttle, over 4k rpms, it reads 12.7-13.5.

The 16.5-17 sounds very lean to me, but I did not hear any detonation and the car behaves normally. I did however start to get a CEL, but it goes away when I turn the car off and back on. I wanted to make sure this is normal before I start the MS install.

Thanks in Advance.

That's lean, but being NA and nearly stock without detonation, you should be fine. Is the car breaking up any while at 16.5-17?

Sounds like the AEM is miscalibrated.

What do you mean by breaking up?

I'll look into AEM calibration.

Misfire. A studder, or miss resulting in a slight jerking motion.

if you removed your narrowband o2 are you sending a signal to your stock ecu using narrowband simulation from the AEM? Sounds to me no. When I had my stock ecu in closed loop the feedback would hunt between 14.5 to 15.4 and if I went wot it would read 12s as it climbed past 4-5k than hit down to high 11s above 6500

If the ecu doesn't have o2 readings it will default to using whatever sensors and fuel maps for them, and with the cone filter it would bringing more air than normally so it would throw off the fueling, esp without ability to compenstate.

If the aem is wired to the stock ecu make sure its on the correct output mode of 0-1v narrowband sim

As far as I can tell, the car is not missing and pulls just as strong as before.

I have the the AEM wideband set to "P0". And wired as follows: the red wire to cig lighter, black to ecu ground and chassis ground under dash, white wire to blue/red wire in place of OEM O2 sensor, and the blue wire is unused.

Should I have the wideband set to "P3"? I have tried looking for instructions from AEM but I can only find them for the UEGO controller.

Thank you for the fast replies.

For my AEM it was to be set to P04\P4 for narrowband sim

P0 was wideoband 0-5v output mode.

I have changed the setting on the AEM wideband to P04/P4.

It now reads 13.5 on warm up idle, 14.7 - 15.3 on idle after its warmed up. I still read 15.8 - 16.1 on 10% throttle, under 4k rpms cruising. It reads down to 11.3 on full throttle from 4.5k up to red line.

My CEL also came back on after 30 minutes of driving. But the CEL disappears every time I turn the car off and back on. I started to notice the car seems a little slower under 4k rpms and then seems a little faster after 4.5k rpms. That part my just be in my head. There is still no detonation that I can hear.

These reading are closer to what I was expecting, except for the 15.8 - 16.2. It still seems lean to me. But is this closer to what it should be reading?

That should be correct, under cruise you don't need to be using much gas. I've tuned with my MS to be at 15.5. Could/should go leaner to save more gas, but couldn't be bothered.

^ with curly. The numbers sound like exactly what it should be doing.

Awesome, thank you very much for your help. Now that this is sorted out, the the MS DIYPNP will go in this weekend. With the MS I will have the change the calibrations of the AEM WB back to P00, correct?

Thank you.

yes just change it back to P00 for 0-5v wideband output.

^Thank you.

I did notice something today while driving to work. I was driving at cruising speed, under 4k rpms, 10% throttle, reading 15.8-16.1, when the reading suddenly dropped to 13.7 for a few seconds and then went back to 15.8-16.1. Then my check engine light came on. Car did not feel any different. Does anyone have any ideas as why my car is doing this? Will this affect me when I install the MS?

could be bad grounding on the AEM, where did you pull power and grounds to it from?

I pulled power from the cigarette lighter. I used the ECU ground under the throttle body and I added a 2nd ground under the dash.

I ran my ground to straight to the ground coming off the ECU wiring harness in cabin and it cleaned voltage difference to the ecu alot.

I'll give that a try this weekend. Thank you.

Did you get your problem resolved? Are you happy with the AEM WB?

I wouldn't get an AEM wb, I recommend looking at a 14point7