Map Switching With EcuTek

Reading Short and Long Term Fuel Trims with Map Switching to determine Ethanol content 

• Map 1 - Pump Gas(E10)

• Map 2 - E50 (20% More Fuel/Half ethanol half gas) 

• Map 3 - E70 (30% more fuel/Filled with E85 but had gas in the tank) 

• Map 4 - E85+ (Full tank of E85, filled from a tank of ethanol)

(E85 requires 43% more fuel than pump gas and for cars with only Direct Injection e40/50 is recommended as the max you will make more power this way) 

 You will be reading a combination of short and long term fuel trims at idle. For example, if short term fuel trims read +2% and long term fuel trims read -1% you have a total of +1% fuel added. With a STFT of -5 and a LTFT of +5 the is equal to 0. The idea is to have Total fuel trims at 0 at idle for each map and mixture. This means you are at the exact content, 

  example map 1 with e50 will show +20% but map 2 for E50 should show less than a few %. If you fill with e85 and map 4 shows 0-5% corrections at idle you have the correct map. 

 When adding Ethanol to your tank, you must use the fuel in your fuel lines before switch maps, due to the fuel system design, once fuel is pressurized in the lines it does not return to the tank, so you must burn the pump gas before you change maps.  

When you add ethanol, you will bring up short and long term fuel trims in data longing, start the car, and drive away from the station. When you see the combined fuel trims adding +10% or more at idle you will change maps and continue to drive soft a few more miles .  

Wrong map? 

If you have pump gas in the e50 map you will see -20% roughly

if you have pump gas on the e70 map youll see -30%

and on the e85 map you would see -35 or more %

If you are in the pump gas map with e50 you will see +20% and if you are in the the puump gas map with e85 you should bee +35 or more %

The stock Ecu on the WRX/86 Can add 40% long term and 40% short term fuel, plus added race rom coding allows for a extra 20 or more %

Even in the wrong map the car should still hit afr target but you will get a cel