Settings Spotlight #5

Welcome back to another Setting Spotlight, Aces people! In today’s post, we’re going to be going over another batch of variables that allow you to keep your Aces EFI system tuned just the way you like it. As always, these will be added to the Settings Glossary in full, searchable form soon.

Let’s get started!

• FPS x Point:
  Defines the voltage breakpoints for the fuel-pressure sensor calibration (volts).
  Change them only to match the installed sensor's voltage-to-pressure data, keeping each voltage paired with the correct pressure value.
• Fuel Inj FPS Compensation:
  Enables injector-flow compensation using measured fuel pressure.
  Turn it on only when a correctly calibrated fuel-pressure sensor is installed and the pressure reference is configured; otherwise leave it off.
• Fuel Learn:
  Enables long-term fuel learning from closed-loop oxygen-sensor feedback.
  Turn it on after the base fuel and target-AFR tables are reasonably close; turn it off during diagnosis or when you need the calibration to remain unchanged.
• Fuel Learn Cycle:
  Sets how often the ECU updates long-term fuel learning. A shorter cycle learns more quickly but may react to transient noise; a longer cycle learns more slowly and smoothly.
• Fuel Learn Max Limit:
  Sets the maximum positive fuel correction that long-term learning may store or apply.
  Raise it only when the base tune is known to need more correction; lower it to prevent large learned enrichment from hiding a calibration or hardware problem.
• Fuel Learn Min ECT:
  Sets the minimum coolant temperature required before fuel learning begins.
  Raise it to prevent learning during warm-up, or lower it only when the engine and oxygen sensor are stable enough to learn accurately at cooler temperatures.
• Fuel Learn Min Limit:
  Sets the maximum negative fuel correction that long-term learning may store or apply.
  Make it more negative only when the base tune legitimately needs fuel removed; keep it conservative so learning cannot hide a sensor or fuel-system problem.
• Fuel Learn Rate:
  Sets how aggressively long-term fuel learning changes the stored correction.
  Increase it for faster learning, or decrease it for smoother, more conservative updates when the learned table is unstable.
• Fuel Learn Read Coef:
  Controls how strongly the stored fuel-learn correction is applied.
  Increase it to use more of the learned correction or decrease it to soften its effect; change it only when validating the learning strategy.
• Fuel Loop:
  Enables closed-loop fuel correction using wideband oxygen-sensor feedback.
  Turn it on for normal self-correction after the sensor and target AFR are verified; turn it off for open-loop testing or sensor troubleshooting.
• Fuel Loop Min ECT:
  Sets the minimum coolant temperature required before closed-loop fuel correction begins.
  Raise it to keep warm-up fueling open loop longer, or lower it only if the wideband is active and stable sooner.
• Fuel Power On Percent:
  Sets a global fuel offset percentage applied by the fuel strategy.
  Increase it to add fuel broadly or decrease it to remove fuel; use it only for temporary overall correction, then fix injector, pressure, or VE settings if the offset is consistently needed.
• Fuel Prime Percent:
  Sets the amount of priming fuel delivered when the system is powered on before cranking.
  Increase it if the engine needs more fuel for the first start attempt; decrease it if it floods or produces a strong fuel smell before cranking.
• Fuel Self Learn Table:
  Displays or stores the learned fuel correction by operating cell. Positive values add fuel and negative values remove fuel.
  Review the pattern to improve the base fuel table, and edit or clear cells only when correcting known bad learning.
• Fuel System Pressure:
  Sets the reference fuel pressure used to calculate injector delivery.
  Enter the actual pressure differential at which the injector flow rating is specified; an incorrect value will make the entire fuel calculation inaccurate.
• Idle AFR:
  Sets the commanded air/fuel ratio at idle when the single-value idle target is active. A higher number is leaner and a lower number is richer.
  Adjust it for idle quality, emissions, and fuel stability while watching misfire and exhaust temperature.
• Inj Startup RPM:
  Defines the engine speed breakpoints used by this table (RPM).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• Injector Off Time:
  Defines injector dead time/offset across battery voltage.
  Enter data for the installed injectors and fuel pressure; incorrect values cause fueling errors that are most noticeable at idle and low pulse widths.
• Learn MAP x:
  Defines the manifold pressure/load breakpoints used by this table (kPa).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• Learn RPM y:
  Defines the engine speed breakpoints used by this table (RPM).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• Loop Max Limit:
  Sets the maximum positive short-term closed-loop fuel correction.
  Increase it only if additional enrichment authority is needed; reduce it to prevent closed loop from masking a base-fuel or hardware problem.
• Loop Min Limit:
  Sets the maximum negative short-term closed-loop fuel correction.
  Allow more negative correction only when necessary; keep the limit conservative so closed loop cannot remove excessive fuel because of a bad sensor or base calibration.
• MAP Acceleration Decay Rate:
  Controls how quickly MAP-based acceleration enrichment fades at each temperature.
  Increase values for a faster decay or decrease them to keep enrichment longer; adjust when the initial response is correct but the mixture afterward is not.
• MAP Acceleration Enrich vs ECT:
  Sets MAP-based transient enrichment versus coolant temperature.
  Increase values where rapid load changes go lean, especially when cold; decrease them where the engine becomes too rich during the same transition.
• MAP Trans Fuel Table Gain:
  Scales the overall MAP-rate acceleration-enrichment table.
  Increase it if rapid load changes cause a lean stumble, or decrease it if those transitions are too rich; tune after the MAP sensor and base fuel table are correct.
• MAP x Point:
  Defines the manifold pressure/load breakpoints used by this table (kPa).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• MAT Fuel Enrichment:
  Adds or removes fuel based on intake-air temperature.
  Adjust it only when logs show a repeatable fueling error as air temperature changes; avoid using it to mask an incorrect air-temperature sensor calibration.
• MAT x Point:
  Defines the intake-air temperature breakpoints used by this table (°C).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• Mild Fuel Table Offset:
  Applies an overall fuel offset to the corresponding cam/base fuel profile.
  Increase it to add fuel across that profile or decrease it to remove fuel; use only for broad correction, then refine individual VE cells.
• Mild VE:
  Defines volumetric-efficiency/fuel-model values across RPM and load for the selected base profile. Higher values command more fuel and lower values command less.
  Tune cells from wideband data after injector, displacement, pressure, and sensor settings are correct.
• Min Fuel PW:
  Sets the minimum injector pulse width allowed by the ECU across operating conditions.
  Raise it only to stay above an injector's unstable minimum, or lower it when the current limit causes overly rich operation at very low fuel demand.
• Race Fuel Table Offset:
  Applies an overall fuel offset to the corresponding cam/base fuel profile.
  Increase it to add fuel across that profile or decrease it to remove fuel; use only for broad correction, then refine individual VE cells.
• Race VE:
  Defines volumetric-efficiency/fuel-model values across RPM and load for the selected base profile. Higher values command more fuel and lower values command less.
  Tune cells from wideband data after injector, displacement, pressure, and sensor settings are correct.
• Rev y:
  Defines the engine-speed breakpoints used by the target-AFR strategy.
  Change them only to redistribute tuning resolution across the RPM range, keep the points in ascending order, and review the related AFR table afterward.
• RPM y Point:
  Defines the engine speed breakpoints used by this table (RPM).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• Stock Fuel Table Offset:
  Applies an overall fuel offset to the corresponding cam/base fuel profile.
  Increase it to add fuel across that profile or decrease it to remove fuel; use only for broad correction, then refine individual VE cells.
• Stock VE:
  Defines volumetric-efficiency/fuel-model values across RPM and load for the selected base profile. Higher values command more fuel and lower values command less.
  Tune cells from wideband data after injector, displacement, pressure, and sensor settings are correct.
• Target AFR Type:
  Selects how the ECU determines target AFR, such as fixed idle/cruise/WOT values or a full RPM/load table.
  Choose the mode that matches the desired tuning strategy, then confirm the corresponding target settings are configured.
• Target Air/Fuel Ratio:
  Defines the commanded air/fuel ratio across engine speed and load. Higher AFR values are leaner and lower values are richer.
  Change cells to match the engine's idle, cruise, and power requirements while verifying results with a calibrated wideband.
• TPS Acceleration Decay Rate:
  Controls how quickly TPS-based acceleration enrichment fades at each temperature.
  Increase values for a faster decay or decrease them to keep enrichment longer; adjust when tip-in is correct but the mixture stays rich or goes lean immediately afterward.
• TPS Acceleration Enrich vs ECT:
  Sets TPS-based transient enrichment versus coolant temperature.
  Increase values when quick throttle opening causes a lean stumble; decrease them when tip-in is excessively rich, tuning cold and warm regions separately.
• TPS Trans Fuel Table Gain:
  Scales the overall TPS-rate acceleration-enrichment table.
  Increase it if quick throttle movement causes a lean hesitation, or decrease it if tip-in becomes overly rich or boggy.
• WOT AFR:
  Sets the commanded air/fuel ratio at wide-open throttle when the single-value WOT target is active. A lower number commands a richer mixture and a higher number commands a leaner mixture.
  Tune only with a verified wideband and appropriate load testing.
• WOT MAP Threshold:
  Defines the manifold-pressure threshold used to identify wide-open/high-load operation.
  Raise it to require more load before WOT enrichment activates, or lower it to activate the strategy sooner.
• WOT RPM x:
  Defines the engine speed breakpoints used by this table (RPM).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.
• WOT TPS Threshold:
  Defines the throttle-position threshold used to identify wide-open-throttle operation.
  Raise it to require more throttle before WOT logic activates, or lower it to activate sooner; keep it above normal cruise throttle.
• Key On Pump Hold Time:
  Sets how long the fuel pump runs for priming after key-on before the engine is cranking or running.
  Increase it if more prime time is needed to build pressure, or decrease it to reduce unnecessary pump operation.
• Turn Off After Lose RPM:
  Sets the delay before the fuel pump turns off after the ECU loses the engine-speed signal.
  Keep it short for safety, increasing it only enough to prevent nuisance shutoff during brief signal interruptions.
• Turn Off RPM:
  Sets the engine-speed threshold below which the fuel pump is considered eligible to turn off.
  Change it only to match the cranking/RPM detection behavior, keeping the setting low enough that the pump remains on during normal cranking.
• Absolute RPM Error:
  Defines the engine speed breakpoints used by this table (RPM).
  Change these points to place more table resolution in the operating range you need to tune; keep them in ascending order and then review the table values after changing the axis.

That’s all for this week. We’ll continue to work through all 2000+ variables with you every week, right here on AcesEFI.com.

Happy Tuning!