HEMI Technical Info

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FAST Xfi 2 Notes

Start
CTS -warm up fuel
Turn the key on for about a minute before starting (this heats up the O2 so you can trust the reading immediately at start).  Then start the engine while watching the ACTUAL AF RATIO. 
Adjust the CTS correction as required to keep the AF at about 13:1 during warm up.
CTS correction must go to ZERO for closed loop to work.
 - Cranking fuel is just for getting it to fire
 - After start should start almost immediately and should only be active for a short time no longer than 15-20 (5-20) seconds. just enough to get the engine running stable. After that it should be only adding fuel for the enrichment vs CTS
 - IAC should be set near 100 at startup. Depends on the size of engine and injectors. Smaller engines with large injectors like more.
 
Idle
 - AX TPS for idle should be 2% assuming you calibrated the TPS which you must do.
 -  TPS should go between 0 and 100%
 - CTS correction must go to ZERO for closed loop to work
 - NEVER use more timing trim spark adjustment than 5 or 6 degrees. Spark will go way outside limits
 - Throttle follower MUST START AT ZERO or it will hold the IAC open at idle.
 - reset the mechanical throttle to get the IAC down under 30 at idle on a hot engine
 - set all the boxes around idle to about 13.8 - 14.1 AF and timing steady 15 - 25
 - reset the mechanical throttle to get the IAC down under 30 at idle on a hot engine
 - max tps for idle should be 2
 - O2 gain and make sure it is 10-15 where you idle
 
Cruise
The target F ratio is whatever the engine likes. Built engines want 13.5 - 14 (cruise)
VE is a steady state adjustment. You have to ignore accel and decel   If it hunts and pecks even though you got everything else filled out correctly then you idle P and D values are not right. I would start there with 32 in the P and 8 in the D this works well with most cars if you have the idle screw and throttle follower set up properly.
 
Acceleration
AE fuel set to -2 or -3.
closed loop gain table around 25 in the cruise area and 35 in the higher load areas
 
Key info:
 - when learning - If you re-fresh the ve table pressing f3 you will see the new ve numbers,
but you wont see the old ones as they will be over-written by the new numbers.
- Using the "G" key to see a 3D version of the VE table really helps to smooth things out.
- Using the "L" key during closed loop tuning to help select the correct VE value in real time.
 
IAC Status – A numeric code that gives information about the operation of the IAC controller.
15 = Normal operation
14 = Short to ground
13 = Short to battery or open load
12 = Thermal shutdown
11 = ECU control error (disabled)