Still lean problems

[anotheridiot]

2009 Chevy Express Cutaway 6.0. Keep getting permanent lean codes on 02 sensors both banks.

We ran the smoke test thru intake found no leaks. Changed MAF, changed all 4 o2 sensors, still get the same codes.

I got the tune from the repository here, checked files, nothing different. I was hoping someone in Philly or Ohio did something to it. As I was comparing, I see a table that says closed loop vs 02 that is appears to richen the mixture under certain conditions. The entire table is at 0.0.

Down to the last week to go thru emissions. I got Bosch o2 sensors, but the wagners are called OEM design, so I am thinking maybe the way the exhaust is monitored might be different.

Checking underneath with a temp gun thinking we have a blockage in the cats, all temps were noticeably cool. I am talking 320 or so at the exhaust manifold, 190's pre cat, and 130's post cat. The other codes that show up are heater circuit resistance and power to heater circuit. What is the purpose when its 100 degrees here in Chicago, why do the heaters need to work and stay on.

Just trying to figure out the reasoning. I was thinking pull the fuses of the heater circuits, but that will most likely throw a code anyway. Here in Illinois, check engine light on, they wont even plug it in, even if its a code that has nothing to do with the emissions systems.

So be parts changers and get no answers, you look to what might have been done, like gutting cats maybe? Either way, I see a table that is not supposed to do anything apparently, that can richen the mixture and might actually fix the issue, so I thought someone could help.

So far we have just read this vehicle, so I have not played with anything I should not have yet.

[edcmat-l1]

Hold on!

This is a job for........


businessman-looking-into-crystal-ball.jpg

[sgod1100]

Hold on!

This is a job for........


businessman-looking-into-crystal-ball.jpg

YESSSSSSSSSSSSSSSSSSSSSSSS....lmao

[Alvin]

Is this a completely stock van or is it a swap or something?

[Cringer]

2009 Chevy Express Cutaway 6.0. Keep getting permanent lean codes on 02 sensors both banks.

We ran the smoke test thru intake found no leaks. Changed MAF, changed all 4 o2 sensors, still get the same codes.

I got the tune from the repository here, checked files, nothing different. I was hoping someone in Philly or Ohio did something to it. As I was comparing, I see a table that says closed loop vs 02 that is appears to richen the mixture under certain conditions. The entire table is at 0.0.

Down to the last week to go thru emissions. I got Bosch o2 sensors, but the wagners are called OEM design, so I am thinking maybe the way the exhaust is monitored might be different.

Checking underneath with a temp gun thinking we have a blockage in the cats, all temps were noticeably cool. I am talking 320 or so at the exhaust manifold, 190's pre cat, and 130's post cat. The other codes that show up are heater circuit resistance and power to heater circuit. What is the purpose when its 100 degrees here in Chicago, why do the heaters need to work and stay on.

Just trying to figure out the reasoning. I was thinking pull the fuses of the heater circuits, but that will most likely throw a code anyway. Here in Illinois, check engine light on, they wont even plug it in, even if its a code that has nothing to do with the emissions systems.

So be parts changers and get no answers, you look to what might have been done, like gutting cats maybe? Either way, I see a table that is not supposed to do anything apparently, that can richen the mixture and might actually fix the issue, so I thought someone could help.

So far we have just read this vehicle, so I have not played with anything I should not have yet.

Are the O2 sensors reporting any voltage? Like 100mv or 0v?

[anotheridiot]

They start to as new, but then flat line. The front ones keep reading and show a graph, but the second two both flatline.

I know you spit fuel on these things and fry them, but there is nothing coming up as rich.

[anotheridiot]

Is this a completely stock van or is it a swap or something?

stock van that we have not messed with. The MAF sensor had a broken pin, that is reading like .86 then .78 or so as it warms up and the rpm's drop.

[Cringer]

They start to as new, but then flat line. The front ones keep reading and show a graph, but the second two both flatline.

I know you spit fuel on these things and fry them, but there is nothing coming up as rich.

O2 sensors, as the name states, sense the presence of oxygen, not fuel. So if are spraying raw fuel on them (such as a misfire) it will read lean.

You really need to post the tune and log file.