vroom_vroom

iTrader: (5)

Has any one else had problems with a fwi and sending p0171 lean codes (it is 32 degrees outside)

JDMC5

iTrader: (3)

it's caused by the fact that the flow of air going into the MAF is altered. Correct MAF calibration is very important to proper fueling. What happens is that more air passes through the sensor than what is being measured by the maf, creating a lean condition. The computer can and does learn to compensate but some air boxes throw calibration so far off that it forces the computer to add way more than normal amounts which triggers a lean code.

vroom_vroom

iTrader: (5)

But I have had it on for over a month it just started last night?

JDMC5

iTrader: (3)

well, it could be a combination of the FWI and winter gas. Many other things could cause a lean code as well. The only way to know if it's the airbox causing it is to put the stock airbox on and see if the fuel trims go back in line. Or in your case see if the code goes away.

Hawkins04

iTrader: (4)

i have the same thing happening to me right now I have been told by everyone every Lew (diablotuner) our cars run lean from the factory and that put and cai or a fwi make it even worse. I just ordered a stock airbox from a member and will see how everything works out. everyone also said to either do that or get it tuned with a handheld or something

JDMC5

iTrader: (3)

the last monte I tuned with a K&N air box was damn near 20% lean up top.

And yes, the LS4 tune is pretty lean for a stock tune.

Hawkins04

iTrader: (4)

which sucks cause most people even me do an cai first and don't know it could have this effect

vroom_vroom

iTrader: (5)

The thing that gets me is it only dose it when I drive it cold after it fully warms up I can't get the light to come on

Hawkins04

iTrader: (4)

yea my will stay on for a few days (normally the coldest days) then go out a few days then back on as soon as i get the airbox i will be putting it on and see what happens and let you know

evil 5.3

i dont know what year car you have but you can pick up a super chips tuner for our cars use for right around two hundred dollar on ebay and i like mine its not omg difference but you can feel it and i like the shifts now

vroom_vroom

iTrader: (5)

I am getting a Hp tuner when my taxes come back just didn't want to mess up my motor

JDMC5

iTrader: (3)

good idea you'll be glad you did. Like I said, put the stock air box on and check the trims. If everything looks good put the CAI back on and tune your maf.

vroom_vroom

iTrader: (5)

Yea I have been reading the book master efi tuners a lot to take I'n for the mathmaticly challenged

JDMC5

iTrader: (3)

you should pick up greg banish's books, they're pretty good.

vroom_vroom

iTrader: (5)

I'm back to bother you,
I gave read the part on editing the fuel system but it makes no reference to fuel trim? What's is the fuel trim just the afr?

TiredGXP

iTrader: (2)

The fuel trim is the percentage fuel added (+trims) or removed (-trims) based on instantaneous and long-term feedback from the O2 sensor when the vehicle operates in closed loop.

Positive trims indicate that the vehicle is flowing more air than the MAF (or VE table) thinks, so fuel is added to eliminate a lean condition.

The solution is to log fuel trims against MAF frequency and then adjust the MAF table by the average trim. Many people adjust the trim by 1/2 the average amount to avoid overshooting, and then go back and do another log.

We have long-term and short-term trims, so you have to either disable the long-term trims while logging, or log both and add them together to see what all the trims are doing to your fueling. I have the LTFT permanently disabled in my tune.

JDMC5

iTrader: (3)

from what I can gather from your last post, I think your asking about fuel trims and how to adjust them. If your MAF/VE/ injectors etc are not calibrated properly then the computer will be wrong on it's initial guess on how much fuel to add to get the proper mixture which is called stoich (14.68:1). Fuel trims are also refered to as long term fuel trims (ltft) or short term fuel trim (stft). In a nut shell its the computer's attempt to adjust the fueling back to stoich based on O2 sensor feedback. By adding the ltft and stft you get the percentage of fuel the computer is trying to add/ subtract. Ideally you want your trims to be zero or as close to zero as possible. On your car, in it's current state, you adjust the maf curve to get your trims back to zero. If you need more info than that maybe you should PM me.

JDMC5

iTrader: (3)

looks like tired beat me to it.

vroom_vroom

iTrader: (5)

I appriciate the info I have never tuned anything without a 4bbl so that being said this is what I'm wanting to do
Remove the park rev limiter
Remap the maf
And reduce the shift time servos
An mess with my fans(it's a desert out there)

Should I invest I'n the Hp tuner or will the superchips tuner do all this

evil 5.3

go with th hp tuners you cant do all that with the superchips