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Old 26 Oct 2011, 10:01 pm
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Posts: 6
Default Fuel Map Tuning: How to start?

I wanted to learn how to perform ECU tuning by adjusting the fuel map. but i cannot find a good source in the internet. they only say that when you increase the value, the opening time of the injector increases.

Based from this, i plan on performing the following procedure to learn how to adjust the fuel map. please see if my procedure is correct

1. I will record a drive session from the car i want to tune using his stock BIN data. taking note what RPM he exits each individual curve. i will be taking notes of the RPM and Manifold Pressure at each curve exit

2. Based from the reading, i take note of the minimum, maximum, and average RPM and Manifold Pressure reading

3. from these readings, i will adjust by small increments (i dont know by how much, is 1 enough or do i go 5 per increment?) the areas in the fuel map where the min,max,and average values are. I will be using the O2 sensor to check the Air fuel ratio and not let it go rich (below 12.5:1). Since im increasing the values from the stock BIN, i believe i have no fear of leaning the engine.since the only way to go is richer (am i right?)

4. then go another run to check for performance remarks from the driver, lap time,and watch out for occurrence of low power or knocking. i will also be watching the Air fuel ratio at each road curve

5. repeat until the best lap time is achieved

is my procedure correct?

I read an article that i should start from rich then lean the engine out until the desired AFR is achieved. how lean do i have to be in that case?max the Fuel map value?wouldnt it take longer
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Old 26 Oct 2011, 10:16 pm
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Join Date: Aug 2007
Posts: 1,032

It is a pointless process on all modern ECUs. All of them learn the proper fuel/air ratio as you drive. You can mess it up doing it like that and in a few days it will straighten itself out.
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Old 26 Oct 2011, 10:31 pm
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Join Date: Sep 2007
Posts: 287

well not so much to the other answer. indeed all cars fo "learn it as they go, however if your using hondata or cobb tuning system, then it kinda stops that from happening. im not sure the car or the tuning program your using, but usaully they have tutorial videos on the different tuning programs, even if you can find one for your speciffic uinit id suggest atleast going to watch the hondata flashpro tutorials. i think they said you want to increase it by like 10, but watch the tutorials to make sure.

and its not so much about lap time, being as lap time is affected by alot, besides just speed, and its very hard to replicate the EXACT driving pattern pewr lap, basically, you will datalogg, by doing individual gear pulls usaully, like you will datalog, a lets say 3rd gear pull from as low of rpms as you can get to redline, then you go back, review the datalogg of the 3rd gear pull., and you would then either add or subtract points from the AFR blocks per rpm, you dont really wana go rich, or lean, you want to get ample AFR, which depends on the car, for example, i have an 08 civic si, and the optimal AFR at idle for my car is 14.7:1, however under wide open throttle, thats to lean, so optimal AFR under wide open throttle is in between 12.9:1 and 13.1:1... as i said, ample AFR ratios vary by the type of car, you need to figure out what you ample AFR is, datalogg at idle for like a few mins, make sure AFR stays ample at idle, then with the above mentioned 3rd gear pull, you would adjust the AFR very slightly at a time. you keep adjusting them to get them within the premier AFR range. you adjust, then go do a 3rd gear pull again after the adjustments, check the afr again, adjust as neccisary, until you get all the cells at each different rpm to be within the premier range under Wide open throttle.

im not positive, if you are supposed to tune like this for every gera, it would make sense, but you should defintaly make sure( i was looking into tunning my AFR my self with hondata flashpro, but in the end decided to get a ETUNE using the hondata flsh pro.

i learned alot, about tuning, but never finished, i suggest going and wathcing tutorials on hondatas website
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