Secondary O2 Spacer Causes Overfueling

[PerceivedShift]

I was just about to install an O2 spacer to hopefully remove my newly found check engine light. Then I see this post from Matt at EQT:

What doesn't make any sense to me is why this ECU looks at the secondary O2 to control AFRs to any degree? (Im sure someone can chime in here) I think i've also read that this overfueling issue builds over time.

So does this mean I now need a gesi cat and pray that does the trick?

 

[the]

Is this the issue people are working around by reflashing the car once a week?

 

[PerceivedShift]

Is this the issue people are working around by reflashing the car once a week?

Thought of this after I made the post, that might work?

 

[nok513]

I thought the recommendation from EQT was to disconnect the o2 sensor, then reflash, to avoid over fueling. If this helps, here's what my log shows with Baun's 400 cell gen 2 GESI dp (no spacer). Do these numbers look ok?

https://datazap.me/u/nokisme/eqt-stage-2-0?log=0&data=1-2-8-25-31

 

[aaronc7]

Try it and see. It's possible whatever spacer was being used wasn't working correctly. I know other guys who run spacers without any sort of running rich issues.

Factory logic is to add extra fuel when the ECU detects a catalyst that's efficiency level is below the desired threshold. Presumably this is better for emissions and whatnot.

 

[JerseyDrew77]

Try it and see. It's possible whatever spacer was being used wasn't working correctly. I know other guys who run spacers without any sort of running rich issues.

Factory logic is to add extra fuel when the ECU detects a catalyst that's efficiency level is below the desired threshold. Presumably this is better for emissions and whatnot.

I've been using my 42DD spacer since 2017/18 timeframe without any issues or running rich.

 

[StorableComa]

Running a vibrant clone straight spacer with middle insert on my ARM catted DP. No issues with running rich i've seen in my logs. Not EQT tuned though.

 

[ZuMBLe]

Car doesn't even hit setpoint without spacer.

 

[the]

Source: https://www.golfmk7.com/forums/index.php?threads/eqt-stage-2-o2-sensor.390769/

 

[ZuMBLe]

View attachment 250568

Source: https://www.golfmk7.com/forums/index.php?threads/eqt-stage-2-o2-sensor.390769/

End of argument..

 

[CoryJo]

https://www.golfmk7.com/forums/index.php?threads/eqt-e-tuning-q-a.361928/page-163

https://www.golfmk7.com/forums/index.php?threads/eqt-e-tuning-q-a.361928/page-26

 

[Wastegate13]

I recently unplugged mine and now under cruise my afr stays almost dead on 14.7 very occasionally jumping to 14.88 and right back. When it was plugged in it was constantly hunting between 13.9-15.2ish.

 

[the]

I recently unplugged mine and now under cruise my afr stays almost dead on 14.7 very occasionally jumping to 14.88 and right back. When it was plugged in it was constantly hunting between 13.9-15.2ish.

Is this the sensor that's on the downpipe? And I assume by unplug you guys are just pulling the electric end and leaving the sensor in the pipe?

 

[Ezekiel81923]

Yes, you'll want to leave the sensor in the DP. Just disconnect the electrical end

 

[Hoon]

*Can cause over fueling. Some are fine.

It's just something for guys to be aware of now that more people are looking for alternatives to the CEL. As always, P0036 > P0420.