Hey,
I installed a AEM UEGO wideband today, and did a few 2nd and 3rd gear pulls to see what my ARF wad. As far as mods go, I have GM stage 2, injen intake, Vibrsnt hesder/downpipe, and Ark DTS cat back exhaust. I was expecting to be running really rich with the stage 2 tune, but my air fuel ratio was in the mid 12's which in lean. Does anybidy know what could be causing this??? Could there be a problem with the gauge, or am I actually running lean.
Thanks in advance,
Chris

 

do you have a smaller pulley or is it the stage 2 one?

 

with my 2.99 on stage 2 my afr was 11.2-11.7
and i have header down pipe cat back ported throttle body and 3 inch intake

so what pulley are you runnig

 

Pulley shouldn't matter. The tune has a set AF and it will just work the injectors harder to get it with a smaller pulley.Or so it has been said.

 

I just have the stock GM stage 2 pulley. I just dont understand how I could be running lean with my mods. Also GM installed the stage 2 kit, and I am asuming that they did the reflash correct because the car redlined at 7200 after they installed the kit. That is why I am leaning toward it being a problem with the gauge or sensor. The stage 2 has been on the car for about a year now, andif I was running this lean the whole time im sure that I would have had problems bu now. I just purchased a 2.9 inch pulley but, am def not going to be putting that on untill I get this straightened around.

 

you should say within reason. the injectors can only work so hard.

 

RL should be just 7K.

I figured that would be obvious. Even with a 2.9 it will have really high IDC's but it was pertaining to how the GM tune adjusts.

 

My mistake, redline is 7000. I dont know why I said 7200..... lol

 

never assume it's obvious all of a sudden someone is bitching your head off because he thought the 2.7 would be fine on stock injectors since they adjust.

 

What's the outside temps?

 

pretty warm in jersey today... was 40's by me. i was outside in a short sleeve

 

where is the sensor positioned at? is it after the cat or before? do you have a cat?

i saw the vibrant h/d now. lol, so where is the sensor located on the downpipe?

 

that was my next question^

 

I had the bung welded in before the cat, in the downpipe. I know that if the sensor is placed after the cat, it will mess up the readings.

 

so I'm guessing that if the widebsnd is placed after the cat you will see a "leaner" afr?

 

What position is the sensor? It needs to be at 6'oclock for the best readings...it may be a faulty o2 sensor as well, or maybe you have a huge leak somewhere? Check your connections along the intake.

 

That's correct, since the cat burns up some of the fuel remaining in the exhaust.

According to Innovate, that's the absolute worst place to have it, something about condensation that can build up in the bottom of the pipe then turn to steam and ruin the sensor. Readings should not matter where in the DP it is.


To the OP: It may be possible that it's reading off, but the only way to know for sure is to take it to a dyno with a sniffer and do a pull. Maybe if you're friends with a shop you can talk them into letting you do one pull for $25 or something just to see. I think the O2 sensor on my Innovate is bad - keeps saying I'm cruising around 14.3 instead of the 14.7 it's commanding, but the only way to know for sure is take it to a shop or put someone else's WB in, unfortunately.

 

I was told that 6'0clock was the best reasoing, might be wrong but condeentation seems to collect at the highest point.

 

I had the bung welded in in the 3:00 position, so I know that the position is not the problem. Does anybody know if there is a way to test the bosch sensor to see if it is bad. I am hoping that it is a problem with the sensor, and I am not actually running lean on a stage to tune and stage 2 pulley.

 

You from TR? I'm in Brick.

 

Yes, I am from Toms River.... I live like 2 minutes from the ocean county mall....

 

No ****? Not many modded ss's around here. I've only seen 1 other besides me.

 

yeah, you def dont see to many around here lol...

 

Condensation is water - when it collects it pools at the bottom, just like on an ice cold class of water. Having the O2 at 6 o clock means the condensation would rest right next to it. If you start the engine, that'll turn to steam and according to my manual that can damage it. I have no idea if that's valid, but everyone I've talked to said it's better to have it at or above the halfway point (3 or 9)

OP: Unfortunately there's no way to test the sensor by itself that I know of. You would need to swap in a new sensor and see if it's reading the same, or take it to a dyno.