Say I was wondering if some of you guys can clear something out for me. I was reading alot of the threads here and I came up to one that says that when he/she changed their exhaust system that their evo ran funny. A few people replied and said to reset the ecu by removing the negative cable so the ecu can re-adjust for the "free flowing" exhaust. Is this true? But then there was one who said he put a HKS exhaust and he didn't even have to reset the ECU.

 

You should not have to.

 

i had to reset the ecu after i installed my hks intake. i already had 9000 miles on it. i guess it's not big deal if cel comes on or not. just disconnect the negative cable for a while and attach it back on. problem sovled.

 

Maybe it's a good idea to reset after mods? Disconnect the battery and step on the brake for a 10 or so seconds to drain it.
I am still stock so there are many other people who no more

 

Actually no, you do not have to reset your ecu because your ecu has a technology called "fuzzy logic" which means it will self adapt or learn if you will...... It will compensate when more or less air or fuel is taking in.......

Resetting the ecu just makes this process faster because it starts learning right away once resetted.

 

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It will learn, but the ecu can take up to 500 miles to reconfig its fuel maps,versus just adjusting to the change.

 

Yep.. The ECU reset really speeds things up.. The long term fuel trims and timing tables are the things that are relevent.. If you just drive the car for a few days (From a full cycle, that is, cold engine, warm, and then some performance load, and A/C on) But if you reset the ECU, the long term fuel trims, and default timing tables are reset, so it starts "From scratch" And takes less time to learn.. This also helps if you get the secondary maps (low octane maps) and the car feels "Underpowered" after a tank of bad gas..

 

Thanks for all the response guys. It was really helpful. I am planning on a full exhaust system from the downpipe all the way back. So I guess instead of buying the parts one by one and resetting the ecu, I will just have to save enough money to buy everthing at once so I will have to reset the ecu once.
thanks again!