FUEL TRIMS Tab
[-] FUEL ADJUST
INJECTORS
Fuel table factors are used to scale fuel table cell values. They represent the actual value of a fuel
table cell with a value of 1. The maximum raw value of a cell is 255. Increase the factor to increase
fuel across the map.
- SD FACTOR - Fuel table cell factor for MAP load tables.
- MAF FACTOR - Fuel table cell factor for MAF load tables.
- BASE - This is the actual stock injector size installed when base tunes are developed.
- CURRENT - This should be the currently installed injector size.
- ALTERNATE - This can be used when switching between alternate fuels. This factor is used when USE ALT INJECTOR SIZE is set when switching to either ALTERNATE MAPS or SET2 MAPS
- INJECTOR BATTERY OFFSET - Sets the time in msec required to open an injector based on battery voltage.
- INJECTOR CLOSE TIMING - Sets the injector closed timing based on RPM. Negative values are ATDC exhaust stroke. Positive values are BTDC exhaust stroke.
Cranking Mode
Cranking mode begins when the starter is engaged and ends when either the starter is released
or MAX RPM is reached.
While in cranking mode, cranking IPW is set from the Cranking Injector Pulsewidth table
and then reduced by the factor from the Cranking RPM Factor table.
The active injector size factor is then applied.
When the starter is released, or the MAX TIMER expires, cranking IPW is decayed at the DECAY FACTOR rate. Timer expiration does not cancel cranking mode.
The normal IPW is constantly calculated and compared to cranking IPW. If cranking IPW is greater than normal IPW, Injector PW is set to cranking IPW. This smooths the transition from cranking mode to normal operation. Note that TTIF FACTOR increases normal IPW for some engines while cranking mode is active.
While cranking mode is active, the injectors are fired in batch mode. The IPW in batch mode is half of the logged Injector PW value. In batch mode, all injectors are fired once every crank revolution (every other cycle). When cranking mode is exited, and cylinder 1 sync has occurred, batch mode is exited and sequential injection begins.
- MAX RPM - Once the engine reaches this RPM, cranking mode is exited.
- DECAY FACTOR - Sets the rate at which the cranking IPW is decayed.
- MAX TIMER - Sets the maximum amount of time for cranking mode. When this timer expires, cranking IPW is decayed at the DECAY FACTOR rate.
- TTIF FACTOR - Total TIF is multiplied by this factor to increase the normal IPW calculation during cranking mode.
- Cranking Injector Pulsewidth - Sets the cranking IPW based on ECT.
- Cranking RPM Factor - Reduces cranking IPW based on RPM.
While in cranking mode, post start enrichment, or Post Start Trim, is initialized from the INITIAL ENRICHMENT table. When cranking mode is exited, Post Start Trim decays at a rate based on either WARM DECAY or COLD DECAY, depending on ECT at startup above or below WARM DECAY ECT. The decay is subtracted from Post Start Trim every 100msec.
- WARM DECAY - Sets the Post Start Trim decay rate when startup ECT is above WARM DECAY ECT.
- COLD DECAY - Sets the Post Start Trim decay rate when startup ECT is below WARM DECAY ECT.
- WARM DECAY ECT - Selects the Post Start Trim decay rate.
INITIAL ENRICHMENT
- INITIAL ENRICHMENT - Sets the initial Post Start Trim based on ECT.
ECT enrichment, or ECT Trim provides extra enrichment during warmup based on ECT. ECT Trim can be reduced by the factor from the RPM FACTOR table based on RPM.
- ECT ENRICHMENT - Sets ECT Trim based on ECT.
RPM FACTOR
- RPM FACTOR - Provides a means to reduce ECT Trim based on RPM.
IAT FUEL TRIM
IAT fuel trim, or IAT Trim, provides a means to either add or subtract fuel based on
density corrected IAT.
NOTE: IAT Trim is applied ONLY when the active load source is MAP.
- IAT FUEL TRIM - Sets IAT Trim based on density corrected IAT. Positive values increase fuel.
The calculation is:
density corrected IAT = (IAT x factor) + (ECT x (1 - factor))
- Enable Density Correction - Enables density correction. If disabled, IAT alone is used in place of density corrected IAT.
- Density Correction Table - This table, based on MAP load and RPM, contains factors that are the percentage of IAT to be used to calculate density corrected IAT. The MAP and RPM scales can be edited.
BOOST FUEL COMPENSATION
Boost fuel compensation, or Boost Trim provides additional fuel based on MAP and can be
used to simplfy tuning when increasing boost pressure.
NOTE: Boost Trim is applied ONLY when the active load source is MAP.
- BOOST FUEL COMPENSATION - These are factors that are applied to IPW to increase IPW based on MAP, or boost pressure.
BARO FUEL COMPENSATION
Baro fuel compensation, or BARO Trim provides a means to add or subtract fuel
based on barometric pressure to compensate for altitude and atmosphereic changes when
running ITBs using TPS as the load source.
NOTE: BARO Trim is applied ONLY when the active load source is TPS.
- BARO FUEL COMPENSATION - These are factors that are applied to IPW to increase or
decrease IPW based on BARO sensor voltage.
See also BARO SENSOR SETUP.
KNOCK ENRICHMENT
Knock enrichment, or Knock Trim, provides a means to enrichen the fuel mixture when the
timing is being retarded due to knock analysis.
- ENRICHMENT DECAY FACTOR - Subtracted from Knock Trim every 100msec.
- KNOCK ENRICHMENT TABLE - This table contains fuel enrichment factors based on the number of degrees the knock analysis system is retarding the timing.
[-] CYLINDER TRIMS
CYLINDER TRIMING
CYLINDER FUEL TRIM TABLES
These tables provide individual cylinder fuel trim capability.
- CYLINDER FUEL TRIM TABLES - Contains fuel trim factors based on RPM for each individual cylinder. Factors greater than 1.00 increase fuel, less than 1.00 decrease fuel.