Weird AFR

[undefined0000]

Alright, got my wideband installed and everything seems to checkout except for a few things.

1. During moderate/city accel it reads 15.2-16.8 or so?

2. During cruise, it reads about 16 and sometimes leans out to 17 or leans the gauge all the way out.

3. BUT under boost (10-13psi or so) it goes down to 11

Anything I should be concerned about/What should I look for?

 

[Colt4G63 also]

Does fuel still spray out of the fuel line by the tank?

 

[undefined0000]

Does fuel still spray out of the fuel line by the tank?

Actually, can't really tell, if it still is, its not nearly as bad. Went out and looked and the connecting piece is a tad wet, but there isn't a puddle anywhere. I'm guessing its still wet from when it was? Not sure how long it takes gas to evaporate off of metal with crap all over it.

 

[DSMbabyy]

Thats about right compared to my car. When your putting around, and especially when you let off it will lean out. Under boost you should be adding fuel to bring it down to 11.5 or so. if your in the 9.5-10.5 under boost you might be alittle rich...

sounds like your doin good to me! you really only need to watch it under boost, thats where youll get into trouble

 

[WES_393]

During idle/cruise your wideband should oscillate between roughly 14-15. The factory tune is pig rich and should be somewhere in the 9's at WOT. During moderate acceleration with some boost, you might see something in the 12-13 range, but that's pretty rare. So your wideband is obviously picking up a lean AFR. Possible reasons:

1. You have an exhaust leak before the sensor which is drawing in fresh air. This is probably the most common reason for lean readings at idle/cruise. Large leaks can even throw off readings at WOT.

2. Your actually running lean. This can be caused by poor fuel supply, vacuum leaks, or even a faulty front O2 sensor.

So I would check for exhaust leaks, triple check for boost/vac leaks, then check fuel supply and front O2.

 

[Vander Nars]

11 wot seems fine.

 

[WES_393]

^ 11 is definitely acceptable when it comes to tuning. Even leaner if you can do so without knocking. But the ECU is tuned from the factory for mid 9:1 AFR's at WOT. So the OP running 11's when he should be in the 9's is a sign of a problem.

 

[Vander Nars]

yeah id say running in the mid to low 9s is super rich, i dont know this platform that well but im guessing the sweet spot for these engine is what around 11.5 to 11.8 ? thats where it is for the my engine but I still run my just a lil richer due to mileage.

 

[undefined0000]

Thanks for the input guys. I traded cars with another DSMer locally and he put his GM MAF and MAF-T on with the 3" piping and 2g elbow, and it riched out the gauge as he was driving the car harder than I've ever driven it. He also created a pretty big exhaust leak from a smaller one I probably had, so that's probably what the case is. Thanks for all of the input!