O2 sensor

[tmsnyder]

The GM TBI based ECMs use a single wire narrow band O2 sensor.

I currently have a wideband installed displaying AFR on the dash.

Must I install the narrow band O2 sensor or is there a way to use my heated wide band O2 sensor while retaining the meter on my dash?

 

[billvv]

You'll need the NB O2 sensor for the GM ECM. Innovate has an O2 sensor that provides two signals; at least one of them can be programmed for either 0-5v WB or 0-1v NB. You can use the other for either the dash AFR gauge or one of the 0-5v analog ports, provided you have the EBL modification to the ECM. The advantage of using the EBL port is that it can be recorded on a datalog for tuning and displayed on the EBL system's 'What's Up Display'..

 

[tmsnyder]

Hi Bill,

Thanks for confirming.

I do have a 0-5vdc output on the AFR meter. I could use a voltage divider to make it 0-1v, it wouldn't have the sharp slope of a NB at 14.7 however.

But seems like an advantage to having a WB on one downpipe and a NB for the ECM on the other downpipe. It's a $20 sensor, not that hard to install so I'll just do that.

My goal at this point is to get it running on a boneyard 7.4l ECM, then I'll look at upgrading the ECM and keep the 7.4L as an emergency backup.

Todd

 

[billvv]

Todd,
That's what I did. One bung on each downpipe and both types of sensors.

You may have seen the other thread where I've been posting the progress of Xfireperformance as they resurrect the EBL after purchasing the assets of DynamicEFI. They are now in the process of offering it as a product. Otherwise, I think it would be hard to find an EBL-outfitted ECM that someone's removed.

 

[Richard RV]

Todd,
That's what I did. One bung on each downpipe and both types of sensors.

You may have seen the other thread where I've been posting the progress of Xfireperformance as they resurrect the EBL after purchasing the assets of DynamicEFI. They are now in the process of offering it as a product. Otherwise, I think it would be hard to find an EBL-outfitted ECM that someone's removed.

EBL ECM at xfire

$1200, out of stock, and the last review on the page is from mid 2024 so it's likely the price will increase.

 

[tmsnyder]

Todd,
That's what I did. One bung on each downpipe and both types of sensors.

I like the idea of being able to see what's happening in the other downpipe

 

[tmsnyder]

EBL ECM at xfire

$1200, out of stock, and the last review on the page is from mid 2024 so it's likely the price will increase.

Wonder if they will offer the EBL mod service to just the ECM. Seems like that used to be an option.

Or just MegaSquirt it.

 

[billvv]

They were a reseller of the DynamicEFI's product, perhaps set up for two TBs and the Corvette Crossfire engine. The blog mentions having FlashII boards manufactured.

If you go the EBL way, you can use the WinLog-EBL digital dash. For free.

 

[RF_Burns]

I do have a 0-5vdc output on the AFR meter. I could use a voltage divider to make it 0-1v, it wouldn't have the sharp slope of a NB at 14.7 however.

The NB O2 sensor senses the presence of oxygen. Its output goes Low (~0.2-0.3V) when it detects oxygen (lean condition) and high (~0.7-0.8V) when it does not detect oxygen (Rich condition). It is not a linear output between the two conditions, it switches low to high and vice versa depending on the presence (or not) of oxygen (I'm not sure about the slew rate between the two states).

I'm not sure how the ECM (OEM or EBL) would interpret a condition where the NB sensor input would get an continuous input hovering around 0.5 volts.

I have a NB and a WB sensor wired into my EBL. The EBL uses the NB for fueling and just displays the WB reading. My WB was a device sold by Dynamic EFI and outputs both WB and switching NB.

 

[billvv]

According to BobR's "Introduction to Tuning, Part 1",

VE Learn:

The WUD has a powerful utility to automatically learn in the VE table values. With a standard narrow band (NB) O2 sensor all areas that the
ECM runs in closed loop can be learned in. With a wide band (WB) O2 unit the entire VE table including WOT can be learned in.