Secondary O2 Spacer Causes Overfueling

[aaronc7]

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.

Yeah, I have disabled all the codes and it will still continuously run the 'catalyst efficiency tests' which sends the lambda momentarily lean/rich back and forth. I didn't notice any downsides to this, just looks a little funny in logs. I'm sure there's a way to fix it, but it was easier to just unplug the rear sensor and disable that single code, so that's what I'm doing currently.

 

[the]

I unplugged my sensor and reflashed today. It was more stable for the first 30 minutes, fluctuating between 14.5-14.8 at idle... but it seems like it's making its way back to the wider fluctuations. Does the ECU need time to stabilize or what?

 

[PerceivedShift]

Im just going to install my spacer and monitor AFRs and fuel trims, if I have to reload the map once a month or so, whatevs...

 

[Knifebright]

*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.

Hi @Hoon et All
can you elaborate a bit on this please. I am stage 1 but currently have a persistent P0036 predated by a P0037. I’ve checked elecrical connections and believe I just need a new rear O2 sensor. Is the idea that having no signal is more of an issue than bad info from that signal?
thank you!

 

[aaronc7]

^ sensor or wiring issue. Check the wiring first, if that is good then yeah get a new sensor.

 

[GTIfan99]

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.

Yeah, it seems counter intuitive, but adding fuel heats up the cats more and increases efficiency of the cats, not your car though.

 

[GTI Jake]

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

Datazap is hard to use on my iPhone, but I don’t see anything out of the ordinary.

 

[Acadia18]

Datazap is hard to use on my iPhone, but I don’t see anything out of the ordinary.

If someone made a Datazap mobile app that worked well, they could make a killing in ad revenue...

 

[Daks]

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

No. The turbo is too small.

 

[GTI Jake]

If someone made a Datazap mobile app that worked well, they could make a killing in ad revenue...

I’m not the guy to develop or fund it lol.

IT isn’t my strong suit, and I lose a lot more money than I make in the parts endeavors.

 

[nok513]

No. The turbo is too small.

Lol, maybe I'll upgrade next year.

 

[PerceivedShift]

So far the vibrant spacer with medium insert seems to have done the trick so far, no engine light for a few days.

 

[JTM88]

So far the vibrant spacer with medium insert seems to have done the trick so far, no engine light for a few days.

Same I have the Vibrant J spacer with the medium insert and never had a code with stage 1. I just went stage 2, so I'll check my AFR in a week or so and see how it's doing.