Qwikrex

Ok I recently had my Field SFC-VTEC dyno tuned. I had a question however. If I were to reset my ecu(pulling the backup fuse), wouldnt the ecu relearn a new fuel map once I started the car back up? If this was the case, wouldn't the piggyback unit be modifying a "new" base map, thereby rendering the settings made on the dyno less than optimal?

greebler

TK421 why arn't you at your post!

Qwikrex

ttt

euclid

i dont think honda factory ecu's can learn anything.... when you get your car tuned it just tuned your piggyback, but your factory ecu is still using the same program. so if you reset your factory ecu it wouldnt make a difference. i think, but i could be wrong.
if you reset your piggyback, then you be back to square one though.

Qwikrex

So honda ecus dont have a learning feature?

Fuminsho

It does "learn"

If you add an intake it will change its fuel maps... if you reset the ecu it will reconfiger itself to the new set up... It will optimize itself for better fuel economy, ping factor, and more. The ECU always monitoring the engine and making changes.

Just because it's not as big as a disktop or laptop computer doesn't mean it's not able to save and change it's programing to meet the current demands on the engine.

Fuminsho

Just to add an after thought... why do you think it's so hard to get real HP from an obd2 equiped car?

Zer0DazE

it does not change fuel maps! the fuel maps are just a starting point and the ecu will compensate (via all those neato little sensors) fuel and timing, to a degree to help make the engine as effiecient as it can.

Fuminsho

"ecu will compensate"

This statement means "change" =P

Of course it starts with a base it has to start somewhere.......

Zer0DazE

nope, it means to compensate
http://thesaurus.reference.com/search?q=compensate
http://dictionary.reference.com/search?q=compensate

i see what your saying, yes the ecu will change the amount of fuel/timing, but the original question was:

"Ok I recently had my Field SFC-VTEC dyno tuned. I had a question however. If I were to reset my ecu(pulling the backup fuse), wouldnt the ecu relearn a new fuel map once I started the car back up? If this was the case, wouldn't the piggyback unit be modifying a "new" base map, thereby rendering the settings made on the dyno less than optimal?"
and the answer to this is no. the fields piece has no affect on the original maps. if im not mistaken all it does is "intercept" the data coming and going from the ecu and engine.

sgT

heres the thing, if you ran the car for say 10000 miles of drive time the ecu
has a certain long term fuel trim modifier stored in memory. lets say hypothetically
that its 10%. That means that its multiplying the fuel map by 10% at all times.
Now, you go and dyno tune your car while the ecu is at 10% plus, thats fine
but when you reset the ecu, now it resets to 0 and then your tuning pretty
much went to waste. This is why you should always reset the ecu before tuning
and not afterwards.

Granted my explanation may have been a little exaggerated, but thats the general
idea of it.

Qwikrex

how many miles does it take before the long term fuel trim modifier takes effect?

euclid

i see, i see, i appologize for posting the wrong info. i thought the ecu was just standard program than ran all the time no matter what the characteristics of your engine..... i dont see any point in tuning then if the ecu will recognize changes and adapt to them accordingly.

jdmitr

All the piggy backs do is take in the signal from the map sensor, and changes it at the rpm you want by changing the out signal to the ECU (what ever % you have assigned) and "tricks" it into making an increased or decreased "map". Very simple!

However they are just that!! Simple!! One thing you will notice if you have a very good A/F gauge (not a auto meter or split second -They both just have pretty lights!!)) like the Greddy A/f w/ O2, you will notice that climate, and elevation changes do dramaticaly affect the tuning of the piggy back unit!! If you go up in elevation your map, and many other things will be affected with less O2!! So you have a different map, but your piggy back unit doesn't know this and still adds the % you assigned!!
So for it to work correctly all the time you would have to constantly monitor your A/F and make changes to the %'s to keep it tune!!
When I had a V-afc I noticed major changes when one day it was 95 out and dry, and the next day it was raining, and 85!!
That is why Hondata, and the stand alones are the best way to go!! They work like your ECU, and make changes to timing and fuel maps all the time, and they make corrections as needed with elevation, and climate changes at the %'s you assign!!

Piggy backs are good for the $ if you spend $300 on a good A/F so you can make changes as needed!!

I have seen that the Greddy A/F Gauge with O2 was VERY close to the Lambda when I Dynoed my car!!! I was VERY suprised!!! Better than paying $2000!!!

Just my $.02!!!