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v3settingsreverttodefaults [2012/04/01 07:19]
twdorris
v3settingsreverttodefaults [2013/12/03 11:11] (current)
dmertz [Low battery voltage while cranking]
Line 48: Line 48:
  
 ==== Low battery voltage while cranking ==== ==== Low battery voltage while cranking ====
-This situation is far more common than the missing MFI relay case.  ​ 
  
-In this situation, someone'​s car simply does not maintain good battery voltage while cranking. ​ This can force the ECU to reset and lose all factory learned settings (fuel trims, idle settings, etc.). ​ But this will also lose any recent ECMLink **ECU Config** changes as well!+ 
 +This situation is far more common than the missing MFI relay case. 
 + 
 + 
 +In this situation, someone'​s car simply does not maintain good battery voltage while cranking. This can force the ECU to reset and lose all factory learned settings (fuel trims, idle settings, etc.). But this will also lose any recent ECMLink **ECU Config** changes as well! 
  
 The scenario goes like this. The scenario goes like this.
  
-  ​- Engine is off and customer makes changes to **ECU Config** settings. + 
-  - Customer hits **Save to ECU** and then tries to start the engine to test these new settings.+  ​- Engine is off and customer makes changes to **ECU Config** ​ settings. 
 +  - Customer hits **Save to ECU**  and then tries to start the engine to test these new settings.
   - Battery voltage drops too low while cranking and forces the ECU to reset.   - Battery voltage drops too low while cranking and forces the ECU to reset.
-  - **ECU Config** settings are lost and ECU powers back up with previous settings. +  - **ECU Config** ​ settings are lost and ECU powers back up with previous settings. 
-\\  + \\ The ECU reset occurs so fast that you don't even really notice it. The only indication you'll have is that the check engine light will come on for 5 seconds like it normally would when the ignition key is first turned on. So watch for this as your clue that something is wrong while you're cranking the engine. If you see your check engine light suddenly come back on, then that's a problem. 
-The ECU reset occurs so fast that you don't even really notice it.  The only indication you'll have is that the check engine light will come on for 5 seconds like it normally would when the ignition key is first turned on.  So watch for this as your clue that something is wrong while you're cranking the engine. ​ If you see your check engine light suddenly come back on, then that's a problem.+ 
 + 
 +The other issue you'll run into is that the ECMLink laptop application will have no idea that the settings were lost. So when you look at the settings in the ECMLink application,​ things will appear as they were when you last hit **Save to ECU**. If you exit the ECMLink application and start it back up or simply hit "​disconnect"​ followed by "​connect",​ the application will re-read all the settings from the ECU and you'll see that your settings are not what you intended them to be. 
 + 
 + 
 +But unless you do that, ECMLink will just show you what you last saved…not what's really inside the ECU. So that can definitely add to the confusion. 
 + 
 + 
 +By far, the BEST way to solve this problem is to replace the battery with one that is capable of sustaining sufficient voltage to the ECU while cranking. Check for corroded terminals or ground connections as well. 
 + 
 + 
 +But if that's not possible, you can always go into **Direct Access** ​ and make some trivial change to a setting there and hit **Save to ECU**  before you attempt to start the engine. That will force the current **ECU Config** ​ settings to flash so that even if the ECU resets, it will just start back up with your recent changes from flash. 
  
-The other issue you'll run into is that the ECMLink laptop application will have no idea that the settings were lost.  So when you look at the settings in the ECMLink application,​ things will appear as they were when you last hit **Save to ECU** If you exit the ECMLink application and start it back up or simply hit "​disconnect"​ followed by "​connect"​, the application will re-read all the settings from the ECU and you'll see that your settings are not what you intended them to be.+Another option would be to make your **ECU Config**  ​changes, turn off the ignitionwait for the MFI relay to click (6-10 seconds later) and then turn the ignition key back on and crank as normal.
  
-But unless you do that, ECMLink will just show you what you last saved...not what's really inside the ECU.  So that can definitely add to the confusion. 
  
-By far, the BEST way to solve this problem is to replace ​the battery with one that is capable of sustaining sufficient voltage ​to the ECU while cranking ​Check ​for corroded terminals or ground connections as well.+And one final work around would be to simply leave the engine running. As long as you don't have to restart ​the engine, the settings can't get droppedWhen you do turn off the ignition, though, make sure to wait at least 6-10 seconds ​for the MFI relay to click off before attempting to start the engine.
  
-But if that's not possible, you can always go into **Direct Access** and make some trivial change to a setting there and hit **Save to ECU** before you attempt to start the engine. ​ That will force the current **ECU Config** settings to flash so that even if the ECU resets, it will just start back up with your recent changes from flash. 
  
-Another option would be to make your **ECU Config** ​changes, turn off the ignitionwait for the MFI relay to click (6-10 seconds later) and then turn the ignition key back on and crank as normal.+Beginning with V3 firmware version 3.24.143 (V3lite) or 3.24.144 (full V3), when presented with a momentary drop in battery voltage the ECU will attempt to avoid losing ​changes ​and reverting to the previously-saved configuration or to defaults. Howeverif the voltage drop persists ​for too long, the ECU will still revert ​the settings.
  
-And one final work around would be to simply leave the engine running. ​ As long as you don't have to restart the engine, the settings can't get dropped. ​ When you do turn off the ignition, though, make sure to wait at least 6-10 seconds for the MFI relay to click off before attempting to start the engine. 
  
-Obviously these work arounds ​are only needed if you have this battery reset issue. ​ As long as battery voltage is maintained to the ECU while cranking, then you don't need to do any of these things. ​ Settings will just work naturally then.+Obviously these workarounds ​are only needed if you have this battery reset issue. As long as battery voltage is maintained to the ECU while cranking, then you don't need to do any of these things. Settings will just work naturally then. \\
  
v3settingsreverttodefaults.txt · Last modified: 2013/12/03 11:11 by dmertz