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Subject learning haltech's ECU manager/tuning (long post)
     
Posted by Mizzuh on February 25, 2017 at 5:02 AM
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Message Let me begin by saying, I have absolutely no clue how to tune an ECU. nor can I afford a 10 grand class to learn. But I'm interested as hell and trying to learn all I can for free.

So I downloaded Haltech's ECU manager, and a vg30dett base map from there website and started poking around. So far I've got through the fuel section of the manager. Basically I'm trying to figure out if I understand the sections/values correctly, or if I'm way off (my interpretation is listed as "Field value" and "Notes".) Any correction or further explanation is HIGHLY welcome.

The list is just of the Fuel subsection:

? Base
Description: This table determines the base amount of fuel. All corrections to injector opening will be applied to this table.

Field Value: Percent

Notes: The x axis is based off engine load (Generally determined by reading a MAP/MAF/TPS sensor). The y axis is engine speed (RPM of the engine). The values are how long the injector sprays for during a certain load at a certain RPM (i.e. idle@1000rpm, half throttle@3400rpm, WOT@6500rpm, etc)

? Target AFR

Description: The values in this table represent the target Air Fuel Ratio that the ECU will use for its calculations.

Field Value: Stoichiometric ratio (AFR)

Notes: The ideal AFR is 14.68 parts of air to 1 part fuel (14.68:1) this is the ratio of air to fuel that allows the oxygen and fuel to burn completely, but the most efficient AFR depends on a few different variables such as temperature, the engine’s rpm, air density, or engine load (MAP/TPS input).

? INJ Dead Time
Description: This table will compensate for the delay in opening the injector when battery voltage varies. If the voltage is low, the injector will fire late.

Field Value: Milliseconds

Notes: (i.e. If your battery is at 12 volts, it takes 1 millisecond to send the "fire" command from the ecu to the injector. So you would put 1.0 in the 12v section to adjust for the delay, making the injector open exactly when the engine needs it, and not 1 millisecond late)

? INJ Flow Rate

Description: This table represents the actual flow of the injectors if the fuel pressure is not referenced to manifold pressure, then the flow rates will decrease with manifold pressure.

Field Value: cc's

Notes: This is where you put your injector size. (a value of 550 would mean you have 550cc injectors)

? Inj Firing angle

Description: This table dictates the engine angle (btdc) that the injectors will be fired at.

Field Value: Degrees.

Notes: (i.e. if your injector fires too early, you get poor atomization during spark. if it fires too late, you could be spraying fuel after the spark and get crappy combustion)

? Prime Pulse Time

Description: This is the first fuel pulse fired by the ECU. When the ECU first detects RPM, an initial pulse is fired to assist with the engine starting.

Field Value: Milliseconds

Notes: (i.e. If the engine does not immediately fire during cold starts, as it does during hot starts, the Prime Pulse Time could need adjustment for that temperature. You could need 150ms when cold, but only 8ms when hot.)

? Cranking Inj Time

Description: This table is solely used for injection timing while the engine is at cranking speeds.

Field Value: Degrees

Notes: There are 2 RPM columns (0 and 400) 0 RPM is for the first revolution(the first time the injector fires for each cylinder), 400 RPM is the appx. speed of the engine while actually cranking. The injection timing generally decreases the warmer the engine temperature.

? Post-Start Enrich

Description: This is the amount of additional enrichment that will be added once the engine has started

Field Value: Percent

Notes: (i.e. If an engine fires, runs for 2 or 3 seconds and shuts off, the post start enrichment is possibly too lean. I read that some cars require around 50% or possibly more when the weather/engine is very cold.)

? Cool Temp Corr

Description: This is the amount of fuel correction that will be applied across the engine coolant temperatures

Field Value: percent

Notes: (i.e. Lets say you just started your engine, and your coolant temp is 68 deg F. Your engine's fuel needs can vary from what your base map says it should be during operating temp. The higher the coolant temp becomes, the less correction is needed. once the engine reaches optimum temperature, the correction should be 0% )

? Overall Trim

Description: This table allows the fuel injection timing for all cylinders to be corrected. The correction is a percentage adjustment on the overall fuel timing value. Axes Setup can be accessed by pressing the F3 key.

Field Value: Percent

Notes: The ECU uses Fuel Trim to help maintain the ideal air/fuel ratio across the map. Fuel trims could be adjusted for stuff like high or low fuel pressure, increased air flow, or a nasty air filter (not sure why you would adjust trim for that instead of replacing it, but hey, stupid people exist). Reading overall fuel trim during tuning can also point to a problem such as vacuum leak (positive fuel trim – lean) or a stuck open fuel injector (negative fuel trim – rich).

so.... how far off am I with these?

(TL;DR: I'm learning stuff and I like cars)

     
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  • learning haltech's ECU manager/tuning (long post) - Mizzuh 05:02:37 02/25/17
 
     
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