I just got the AEM UEGO wideband and have been using it for a few weeks now, The thing is is that it shows an average a/f ratio of high 15's at idle. But it also oscillates really bad. Is this normal?
15.0 @ 90mph with only a intake and exhaust.
at idle and normal driving the ECU targets 14:7:1 AFR's.
FU Tuning
Is it bad if it idles lean though?
15.0 @ 90mph with only a intake and exhaust.
ok, good, I just assumed it was bad when I pulled my cap off my cutout and it idles between a 16.5 and 17 afr.
15.0 @ 90mph with only a intake and exhaust.
Thats strange, my cut-out has no effect on my AFR at idle.
How close is your wideband gauge to your cut-out?
Probably have some air coming back into your exhaust system and your wideband is picking it up.
just curious, kind of on topic. My car runs a little rich, like 14.1-14.6 on the highway around 3k, and is always changing. Is that an acceptable range, or should it always be spot on around 14.7?
My cutout is back by my rear tire. Its not close to my wideband at all
15.0 @ 90mph with only a intake and exhaust.
shouldnt affect your wideband at all I would think... Unless the cutout is just allowing the gases to escape more rapidly thus not getting an accurate reading. Im just taking a wild guess tho so dont take my word for it. That's weird tho...
"You can only feed them semen for so long before their legs fall off."
15s is fine for idle, in fact I know alot of people with evos that actually have it leaner at idle
Your car will never run a consistant AFR while crusing it will bounce around, for cruising 15s is fine, pity our pcm doesnt fully support lean cruise
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Now it has a new issue. I just a header back full exhaust and intake and when I am at WOT around 5800rpm, the wideband pegs out lean. Shouldn't it run pig rich if my injectors hit 100% duty cycle?
15.0 @ 90mph with only a intake and exhaust.
What else are you running besides your exhaust and intake?
"You can only feed them semen for so long before their legs fall off."
Jason Brantner wrote:Now it has a new issue. I just a header back full exhaust and intake and when I am at WOT around 5800rpm, the wideband pegs out lean. Shouldn't it run pig rich if my injectors hit 100% duty cycle?
Just because your injectors are at 100% duty cycle doesw not mean your car should be running correct. In fact this could be a reason why you are not.
What AFR is it at before 5800, and what does it go to at 5800?
FU Tuning
It will go pig rich from 5k to 5800 then it will peg out lean. And it will stay pegged out lean until it idles for about a minute. Even then it idles around 16.5-17
15.0 @ 90mph with only a intake and exhaust.
So now my wideband always shows its pegged out lean. Sometimes goes back down but after 4k rpm it goes back to pegged out lean again. Is this a sign of a bad O2 senspr on my wideband?
15.0 @ 90mph with only a intake and exhaust.
Duty cycle has absolutely nothing to do with AFR, thats just how hard the injectors are working. If they arent sized properly you can actually damage them running too high of a duty cycle. By contract running too much fuel pressure can also damage them. To me it sounds like your tune needs some smoothing out and possibly bigger injectors, what size are you running right now?
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Thats the thing. Stock injectors, stock tune. Its a wideband issue. I am still looking for a tune
15.0 @ 90mph with only a intake and exhaust.
That sounds like definitely a wideband issue.
What are you using for a ground for your wideband. I know the LC1's are bad for grounding issues.
Under the dash bracket. Everything worked fine before. Wouldnt a bsd ground make the wideband shut off. I thought maybe a bad O2 sensor
15.0 @ 90mph with only a intake and exhaust.
I was right. I replaced the sensor and all is good
