Earlier I was searching for the reason I was getting a CEL p0171 (lean bank 1)

the UG was great (as was this and the other fit forum) in tracing it to a missing bolt on my intake manifold (I never touched it so I have no clue why I would be missing a bolt in such an out of the way place but whatever)

I have since seen a great improvement in my short and long term fuel trim numbers and if all goes well I wont be seeing a CEL for this anytime soon.

But they say short term fuel trims shouldnt go above 8...I want to confirm this with Fit drivers that have Ultraguages in their cars

What short and long term fuel trim numbers are you seeing in your commutes? (short term will go all over the place but after driving a bit you will know your peaks and valleys).

 

wait, what?

Honda wanted $1000 to replace a missing bolt?!!!! That they left out????!!!!!!

Please post the name of the dealer/svc manager/mechanic so they may bow their heads in shame.

And write a letter to Honda USA detailing what you went through. The dealer's incompetence, negligence, and fraud is astounding. They should refund your prior cost to have the maf, coils, and plugs changed.

Congrats on solving this.

 

Glad you got it figured out and it wasn't a major problem to fix. Fuel trims are a percentage over or minus of the base map. So positive fuel trims mean a lean condition and the ecu adds fuel. I was taught that its better to have fuel pulled out than added because of running lean and the possibility of knock under loads. Fuel trims should be a few percent of 0 either way even though what you are seeing seems normal from other posts I've read .
ST and LT fuel trims can go up to 15 percent either way for a total of 30 percent. My fuel trims in the Civic are -3.1 average in the winter and -7.9 or higher but usually below -10 average in summer. That means its using 15 percent less fuel from the base maps.

 

not sure if my numbers are normal so I am asking other fit owners

my short term trim -1 to 20
long term 4-16

cel kicks in after 25, replacing the missing bolt got it back into a range that while high wont result in a CEL....

how about you?

 

A while back I started a thread on fuel trims. Here's where my trims were a year ago:
I did get a confirmation that those numbers a typical on a fit.

Santiad You're correct in that the short term trims vary a lot, they are the front line factor in adjusting the fuel/air mixture.
That's why seeing your trims come down indicates you've plugged he leak.

The UG is a great tool for monitoring systems. Trick is understanding how some of those numbers make a difference.
Your experience has taught me a bit about that - seeing a spike in fuel trims can very well indicate a vacuum leak.

Here's the thread I referenced: https://www.fitfreak.net/forums/2nd-...tml#post960915

It gets a bit involved, but my drawn conclusion is that the Fit's ECU is mapped to return the trim numbers I was seeing running regular fuel even after running premium.
That's another discussion, however_

Let's hope now that that CEL stay off.

K_C_

 

Driving style and city vs highway has a lot to do with how the car runs efficiently. Many years ago my wife's girl friend would take here car on the highway at least once a week to clean out the carbon. I never really paid attention to it but she had fewer problems. I drive a lot of highway so my car is fine but my wife's car has a problem, I dont get why her car runs rough on regular and gets bad mpg even on the highway except to say there is something to Octane requirement increase and how it makes the car more efficient when higher octane is used that offsets the price difference.

 

If a car is driven mildly all the time it tends to build up carbon. The carbon in the cylinder can actually increase compression enough that the regular gasoline will not work as well as higher octane where the increased compression demands it. Running it at high revs, occasionally, and using an additive can help eliminate these problems. Marvel Mystery Oil always has worked for me as the best for cleaning out the combustion chamber.

 

I thought that carbon build-up comes from a car running rich, which a car with electronic ignition shouldn't happen to, don't they only run rich when they're cold?

 

Its nice to see that other people get it. I am finding a lot from epa sites that talk about ORI as a major problem with cars that run lower compression than Honda uses. Timing is a big part of power and mpg that when using premium its more efficient and that even premium gas might not be high enough under certain conditions. When trying to save fuel most people drive very mildly which only cause more fuel to be burnt and more carbon. MMO is a good upper lubricant which next time I am at the store I will get some with some Berryman B12 fuel injection cleaner and make my own cleaner.

 

True. (perhaps you meant fuel injection?) Also octane enhancers will also cause deposits in addition to making cold starts more difficult.

Not only are you paying more for something your economy car doesn't need, but it may make it run worse.

It's fascinating though, to see how well modern marketing works.

 

When my car was pretty much stock I had try to milk as many miles per gallon from it I could by keeping the revs low, coasting as much as I could shutting down the engine while in line at the bank etc.. I got bored with it and only once broke into the low 40s while way down on the Texas Gulf Coast on the way back from Mexico... I was probably under the influence of too many shots of Mescal at the time because I can't remember why the mileage was as good as it was except that the land is fairly flat down there... As I became comfortable with the car I started winding the gears out all of the way and get up to 90 MPH almost every time I drove it and by doing so I was getting better fuel mileage... When I got a Scan Gauge I could see that I was getting more ignition advance when I was driving it the speed limit and if I reset the ECU and drove fast it would advance even higher. As SilverBullet was saying, the more advance the better the performance and fuel mileage.. My car is supercharged with the KWSC high boost kit now and I am still able to get as high as 33MPG but not without adding a shot of home brewed octane booster and winding it up a few times every time I drive it.. I do try to pick up enough speed while going down hill so I don't have to use as much throttle climbing the next hill.. I also coast up to stoplights and stop signs, down shifting to slow down and only applying the brakes when I am nearly slowed to a stop.. Since I do not have a MAF sensor on my GD an Ultra Gauge would be of no more use to me than what I have.. I think that if you just do what the old service station guys told people to do when I was a kid and just go out on the highway and blow it out, you will have a better running car and get better fuel mileage.

 

TEX, You would still get fuel trims and cat temps which really help you see where your air/fuel is at and the timing.

 

I need to check that out.. There are so many things that I have yet to install and for some reason or another I just never get things done... The cat temps would be good to know. I can use them as one more way to trigger the water/methanol injector, if I can get around to installing the damned thing... Do you recall what features I would not be able to use or is the info on the website??

 

I believe just the MAF, the fuel mpg might not be as accurate because of that because know the exact air flow gets the mpg pretty close. My cat temps in the winter are 150 degrees hotter, but still cool enough not to worry. In the summer they are around 1250 and now around 1400. I read some where that 2000 is the danger zone but should not go above 1600 degrees. For 69 dollars its a good investment. When you decide to tune your car you will need a good A/F meter.

Check out the water injection post for the new fuel that you might be able to drive there and get a 5 gallon drum cheap since its made down there.

 

The price is great for what all it does... It just dawned on me how messed up my mind has become, I forgot that I haven't had a cat on my car in about a year and a half... I need to get more sleep and blood flowing through my brain, I am getting dumber every day... Oh well.

 

I guess I should have caught it too. Save your money for the A/F meter instead.

 

I love the ultragauge! I have it hooked up to my daily commuter car (it's a civic - <3 honda's) and it's amazing. So much information it's great.

I had no idea what the short term and long term fuel numbers meant but I do now. Thanks guys!!

Sean

 

I am curious of what your fuel trims are and what grade of gas you use? I have some info to compare it because I have 2 Civics.

 

I am still leery of using an AEM AF/IC as a way of tuning because of the way the ECU is constantly fighting it for control of the A/FR and timing... The Hondata tune seems to be plenty rich and if there was a problem the AF/R and timing would return to the present tune which isn't as likely to cause the problems it would if returning to the stock tune... Having an AF/R meter and the water/methanol setup that can be adjusted from the drivers seat might work well to offset or counter any surprises...I would need to shell out better than $400 to get the Boomslang harness and AF/R meter, I have the AF/IC already... I probably will not need to tune if I have no problems with the Weapon R intake manifold, but I have heard that it has caused N/A engines to run lean and may cause an even worse condition with boost.

 

My only point was to fine tune it, running rich is good but more power and mpg could be found by leaning it to optimal. You need a dyno and I believe your ecu is now tuneable because of what Hondata did to it. You might be able to tune a few different maps like for summer, higher octane and your winter and be able to change them with a turn of a knob. Running rich the motor will survive but there is more HP to be found and still leave a safety margin.

The cars my sons friend tunes with his lap top and that was because of what they put in the ecu. I dont think you need a extra controller but a lap top with a cable and software you can down load from Hondata. I might be wrong but what hondata did was put pins and the controller in the ecu and I might be giving you some bad ideas because you might get yourself into trouble if you knew that and tried to tune it by yourself. But it can be that easy and I recommend going to a dyno to tune it. The dyno will show the VE and that is what needs to be changed and the fuel will adjust to that. You can then see how rich and if knock is present at any load and take out timing.

I hope I did not give you some crazy idea.