couple questions on some fuel corrections

[non-vtec]

hey guys. so far ectune has impressed me fully....works pretty well i must say. some questions i have because I'm not familiar with these types of settings/features. mainly these: ECT and IAT trims individual cylinder fuel trims crank fuel table/maps post fuel start maps i do understand what they do but I'm having trouble understanding the numbers that need to be used when using these features. are the values a percentage of the fuel values from the map? or are they actual fuel values that gets added on top of the fuel value from the main fuel map? or do the all operate differently? hope my question makes sense. thanks

[Bindegal]

Below is my attempt at getting users through some of the tables. See if it makes sense. This will be part of the helpfile included with eCtune. Comments/additions/corrections are very welcome. About tuning fuel and ignition corrections Tuning the fuel corrections and idle is critical to obtaining stock-like driveability of the car. The following pages serve as an example only of how this can be done. The order in which the settings are tuned is somewhat important, as this helps to isolate the impact of each setting as much as possible. Adjusting idle speed Prerequisites: -The fuel tables and Injector offset must already be tuned for a stable air/fuel ratio in the entire load/RPM section where the engine is supposed to idle when warmed up. -Across that same section, ignition timing values should be identical. -Turn off the light, A/C, heater fan and other accessories. -O2 feedback/closed loop should be disabled. -Base timing should be set precisely at the distributor before proceeding. Then complete this procedure to adjust the idle speed: 1) Warm up the engine to its fully warmed-up state, 80 degrees C coolant temperature. 2) Open Parameters, Fuel and Ignition corrections, Idle settings . 3) Input your desired idle speed in the Target idle and Target Idle Map . 4) Move the IACV slider until the desired idle speed is stable. 5) Verify that air/fuel ratio and correct as necessary. Re-adjust the slider if required. Tuning the injector battery offset The Injector battery offset table enables you to compensate for differences in the way fuel injectors and fuel pumps react to variations in battery voltage. Especially with large injectors, tuning this table is important, as every aspect of engine operation depends on it. Prerequsites: -To successfully tune the battery offset, you should have already completed the idle speed adjustments as described above. -The initial injector battery offset selection should already be set to the injector type that resembles your actual injectors the most. -Leave O2 feedback/closed loop OFF. Then complete this procedure to tune the battery offset: 1) Warm up the engine to its fully warm state, 80 degrees C coolant temperature. Watch the coolant and IAT temperatures closely during battery offset tuning. You want to keep them as stable as possible to avoid the ECT and IAT affecting the air/fuel ratio while tuning the battery offset. 2) Go to Parameters, Hardware Settings, Injector Calibration . 3) Notice that the actual battery voltage is highlighted in the table. The object of this exercise is to keep the air/fuel ratio as stable as possible across various battery voltages, modifying each cell as required to accomplish this. 4) Turn on the headlights, heater fan and other accessories to force the battery voltage down. Correct the table as necessary. Higher number means more fuel, lower numbers result in less fuel. 5) Notice that the voltage will drop shortly when accessories are turned on. Use this to tune the lower-voltage settings so that AFR remains stable at all times, even when the headlights and heater fan is turned on at the same time. If possible, you may disconnect the generator from the battery to help tune in the lower-voltage areas of the table. Things you should know about the engine start process 1) During cranking, Crank Fuel map is used - the tables are not. 2) Immediately following cranking, fueling is read from the tables. The Post Start Correction tables are applied according to coolant temperature, in addition to ECT fuel correction . 3) Post Start Correction (also known as \"post fuel\") is active for approx. 20 seconds, which is showed in the datalogs. 4) After post fuel, fueling is read from the tables. ECT fuel correction is applied. 5) Closed loop is activated when the Minimum ECT for closedloop temperature set in Fuel & Ignition Settings, Closedloop is reached. 6) AFR during start up is highly dependant on the Engine Coolant temperature compensation table and multiplier. 7) ....and also ensure that the Injector battery offset is tuned properly before fine tuning engine start. Be warned! All widebands lie! What´s that? Well, here is the explanation. A wideband uses the remaining oxygen content in the exhaust gas to estimate the air/fule ratio resulting from the combustion process. If that fuel does not ignite, your wideband is useless. If too much fuel is injected, it may show up as a lean mixture on your wideband because the air/fuel mixture isn´t ignited fully, or not at all. Oxygen will be present in the exhaust gas, effectively fooling the wideband. A couple of tips to more easily dial in engine start: -If possible, to accurately observe the air/fuel ratio during cranking, connect your wideband to a seperate power source and datalog from the wideband directly, using the software from the manufacturer. -Allow the wideband to warm up fully, then attempt to start the engine. Carefully observe the air/fuel ratio, but also use all your senses to find out what´s really happening. When tuning the start-up, ideally you want to end up with something like this: -When cranking, the engine should ignite about ½ to 1 second after cranking. -RPM should increase quickly to the preset idle speed, depending on coolant temperature, quickly and without hesitating or stumbling. -During cranking and post fuel, AFR is rich, typically 11.0 to 12.0 This is normal. -Engine start should work equally well in all operating conditions and temperatures. Adjust the Engine coolant compensation table as required. /Allan

[blenz]

This is a very helpful thread, would it be possible to explain how to tune the Idle Ignition Correction table since my timing seems to be jumping around quite a bit at idle. Is an idle correction of 3.5 to -3.5 degrees a good amount to use over -300 to 300 rpm?

[calvin]

This is a very helpful thread, would it be possible to explain how to tune the Idle Ignition Correction table since my timing seems to be jumping around quite a bit at idle. Is an idle correction of 3.5 to -3.5 degrees a good amount to use over -300 to 300 rpm?

make sure your car idles around the target idle. Then the ign correction will be less. What you want to do, disconnect IACV, make car idle 500-550 rpm, reconnect IACV. Reset ecu. The car will more likely idle near the target rpm and less jumping with ign.

[TopMountGSR]

Way to go Bindegal.. This should be a sticky.

[calvin]

will be in the new help file