Emissions Problem - Failed Smog

14.7 and not .46? That’s off by a lot thdn?

What about O2 sensor #1? Dead?

 

I would change both i them, if ones bad your afr will read wrong

 

They are probably original. OEM denso? And why replace both ay the same time?

 

I mean replace the first one first and see what happens

 

That’s what I was thinking.

1. Replace O2 sensor, see if it changes air flow and therefore reading / no code.
2. Take through drive cycle. If no code, no cat needed.

Not looking forward to the drive cycle tho

 

Where are you seeing his air/fuel ratio readings? The .46 is his MAF (mass air flow) sensor reading

 

He posted like 10 photos the 2nd one he posted with the engine at idle read .31

 

Actually my read thats fuel rate... all i read was fuel and thought afr.. im at work so I didn’t pay as much attention as I should

 

I'm still only seeing the MAF mass airflow reading unless I'm totally blind (which is possible)

 

No worries I thought I was going crazy lol. He should be able to see his AFR though with that app, and yeah it should hover right around 14.7. It'll change based on open/closed loop but it should stay close to that number unless there's a rich/lean issue which could indicate trouble with the cats

 

Or exhust leak will throw the afr off

 

Well, my exhaust has been smelling rich for awhile, and I do have a gasket lead, can't remember where, but it a common issue for those aging 3.4L engines.

 

Yeah, I didn't scroll to that screen while driving. I'll do another run tomorrow and screenshot.

I'm looking at O2 sensors now.

 

The afr will be the same at idle and any speed

 

Just took it out again for MAF readings:

Warming up:





40 MPH foot on the gas:






40 MPH foot not on the gas:

 

Or were you talking about Fuel rate? It was fluctuating from .8 to 3.3 from warm up to 40mph...


EDIT: Ah, air fuel rate, not fuel rate. I'm looking for afr on this app now...

 

still not AFR. that just shows what the MAF is seeing come through.

I never added mine in Torque but it's a separate display for the fuel/air mixture

 

On another note i dont think my battery ever drops down to 13.2 while driving, mine varrys between 13.8-14.3. But that doesn’t really matter lol

 

It might be worth noting that the AFR readings you get through the Torque app are not the most accurate way to read your AFR...best way to is run an AFR gauge with an O2 sensor welded in before the cats like we do on supercharged/turbocharged engines (I just had one put in a couple weeks ago). I'm not sure if this applies to an N/A motor or not but I was told not to base any hard conclusions off the Torque AFR reading because it wasn't the most accurate way to tell if you were running too lean or too rich. Maybe someone else can shine some light on that though. Still be curious to see what kind of AFR reading your getting even with the app.

 

I spoke again today with the shop that installed the cat previously. They quoted me $252 out the door to replace the upstream or bank one O2 sensor, but wanted me to come in for diagnostics to make sure that it was that sensor and not the cat converter. He said that only 10 to 15% of the time is it the sensor that is bad, it is usually the cat converter. I didn’t mention that the cat is only four years old, while the O2 sensor is 18 years old!