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--- sdveadjcomft [2009/06/11 14:05]
twdorris
+++ sdveadjcomft [2024/03/15 11:16] (current)
@@ Line 12: / Line 12: @@
-====== STEP 2: Check For Close Loop Operation ======
+====== STEP 2: Check For Closed Loop Operation ======
 Make sure the car is able to run in closed loop mode.  Look for a cycling FrontO2 sensor and a "1" in the ClosedLoop log item.  It doesn't have to be running with fuel trims near 0%, but it does need to at least cycle in closed loop mode on its own.  If it does not, you need to make some manual adjustments first to at least get it running in closed loop.
 A good understanding of [[v3combinedft|CombinedFT]] and [[fueltrimupdatepoints|fuel trim in general]] will help a lot with your understanding of this function.
 ====== STEP 3: Data Capture ======
 To use this tool, you need to capture some non-default data from your ECU while you drive around.
-{{  http://www.ecmtuning.com/images/forums/sddata/sdmaploc.png}}
+**NOTE:**  As normally installed, first generation (not Gen 2 or MAFT Pro) MAF translators get their ground from ECU sensor ground via the Mitsubishi MAF connector and draw a moderate amount of current, particularly when powering the GM MAF sensor at higher airflow, so the pressure and temperature readings seen by the ECU will change a little if you later unplug the GM MAF or MAF translator, upsetting the VE table calibration.  Changing the translator's ground from ECU sensor ground to chassis ground instead will eliminate this effect. Cut the MAF translator's ground wire between the translator box and the Mitsubishi MAF connector and connect the end of this wire coming from the translator to chassis ground. Leave the wire end that remains on the translators Mitsubishi MAF connector isolated and insulated.
-Add the following log items to your captured values (F10): CombinedFT, ClosedLoop and MAP sensor
+{{  https://www.ecmtuning.com/images/forums/sddata/sdmaploc.png}}
+Add the following log items to your captured values (F10): CombinedFT, ClosedLoop and MAP sensor.
 The MAP sensor you want to log here is the one you have already configured in your **Manifold pressure (MAP)** field on the ECU Input tabs.  An example of this is shown here.  More details on configuring and installing this sensor can be found on the [[sdsetup|ECMLink - Speed Density Setup]] page.
-When attempting to initialize the **SD VE Adjust (SDRatio)** tool, the application will check your ECU Input tab to locate the MAP sensor.  It will then attempt to find this sensor in your datalog.  Using the image above as an example, you would want to log the GM 3-bar sensor attached to the MDP input in order to use this function.
+When attempting to initialize the **SD VE Adjust (CombinedFT)** tool, the application will check your ECU Input tab to locate the MAP sensor.  It will then attempt to find this sensor in your datalog.  Using the image above as an example, you would want to log the GM 3-bar sensor attached to the MDP input in order to use this function.
+Once you're satisfied that the requirements above have been met, you're ready to grab a datalog.  Let the car idle for about a minute.  Then go drive.  Try to keep the car in closed loop mode as much as possible (more on that in the advanced section).
+====== STEP 4: Run the Adjustment Tool ======
+When you're done, you right click in the graph area and select the **SD VE Adjust (CombinedFT)** menu item.  The application will then make a number of suggested changes to your SD VE table.  You will definitely want to smooth and tweak this data a bit to make it "look nice".  The application is just going to slap numbers into cells that it has data for.  You'll need to extrapolate that data a bit to areas where you don't normally drive if you want to make the table work well in unexpected conditions.
+**NOTE:**  You're basically changing the very data long term fuel trim was previously based on.  So if you're making fairly large changes to MAF compensation, you should consider resetting the long term fuel trim values using the "Reset fuel trims" menu item in the ECU menu.
+====== Advanced Usage ======
+Because this function operates only during closed loop mode, it's handy to try to extend closed loop mode as much as possible so that you get a wider range of data in your logs.  This will produce a larger number of auto-adjustments for you.
+There are several ways you can extend closed loop conditions.  The easiest of which is to simply edit the DirectAccess tables that control when open loop is triggered.  By moving those open loop trigger points "higher", you extend the conditions under which closed loop mode will be maintained by the ECU.
+The image below shows a fairly typical setup for the various open loop threshold tables you can use to extend closed loop mode for this test.  Keep in mind what you're doing here, though.  You're basically telling the ECU to maintain stoich air fuel ratios under more load (LoadFactor) and with more throttle.  This could very well produce a hotter mixture than you'd like to maintain for any lengthy period of time.  So monitor EGTs if possible or if not, just try not to stay under high load/closed loop mode for very long.
+{{ https://www.ecmtuning.com/images/forums/mafadjcombft/olthresholds.png }}
+With that table in place, you can grab a datalog with a bit more load variation.  Personally, I like to find a nice hilly area and apply light throttle to vary LoadFactor between 0.9 to 1.3 while maintaining closed loop operation.  This driving combined with the typical flat road driving (with LoadFactors around 0.6-0.9), combined with typical idle and free rev (LoadFactors around 0.3-0.4) really produces a good set of data for this function.

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