Jeff Hare Posted March 29, 2015 Report Share Posted March 29, 2015 Hi, My subaru has a hesitation when you first apply the throttle and when you let go of the throttle. Â Happens in every gear, even with no load ie free revving. Â It is worse when cold. Â It also happened on the factory ecu before I changed to Link and has been there ever since I bought the car. Â I have a very experienced tuner and he has tried everything he knows of with only a minor improvement. Â Therefore I dont believe it is in the tune but something physical. I have started running logs to troubleshoot why this is occuring. Â I have ruled out the throttle position sensor as the sensor voltage looks good and seems to respond quickly and accurately to changes in the throttle. What I have found is that there is a dip in the fuel injector pulse width when this hesitation is felt. Â I have attached a graphical representation of the logs showing what I have found. What I am missing is the next step, how do I work out what is telling the ecu to have this dip in the amount of fuel causing the hesitation? Thanks, Jeff Quote Link to comment Share on other sites More sharing options...
Simon Posted April 1, 2015 Report Share Posted April 1, 2015 Most likely would be a dip in the MAP pressure. This signal has the biggest impact on the fuelling. Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted April 8, 2015 Author Report Share Posted April 8, 2015 Thanks Simon, I have attached a plot of the MAP signal and it seems to be normal. Â We have increased the delay on the fuel injector so now there is not a dip in the fuel injector pulsewidth. Â However, the ignition angle does seem to be strange. Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted April 8, 2015 Author Report Share Posted April 8, 2015 What could cause a dip in the fuel and ignition? Â (MAP and TPS already ruled out) Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted April 8, 2015 Author Report Share Posted April 8, 2015 Thanks Ross, I have sent the files to you and I hope you can help! Does the ignition directly follow the fuel pulsewidth? The problem is much worse when the engine is cold. Â Do you think this could be a clue or is that normal behaviour if there is a dip in fuel? Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted September 21, 2016 Author Report Share Posted September 21, 2016 Most likely would be a dip in the MAP pressure. This signal has the biggest impact on the fuelling.Thanks Simon, could it be a delay in the MAP sensor reading instead of a dip? I have attached a plot Quote Link to comment Share on other sites More sharing options...
Simon Posted September 21, 2016 Report Share Posted September 21, 2016 Looking at that the fuel is increasing as the throttle is applied and then it looks like the overrun fuel cut is activating?Putting up a copy of the MAP and a copy of a full PC log will help. https://www.youtube.com/watch?v=_P1LRANeO4A Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted September 24, 2016 Author Report Share Posted September 24, 2016 Thanks Simon, i am working on getting the logs.In the meantime, I noticed that my ecu is configured to use a V7-9 Map sensor. The map sensor is Subaru part number: 22627-AA170. The version numbers on the Link ecus confuse me. I notice there are 3 choices for a Subaru map sensor: V1-6, V7-9 or V10. Can you tell me if I have the right Link ecu setting for the above subaru map sensor part number? Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted September 25, 2016 Author Report Share Posted September 25, 2016 I tried setting the Map sensor to the V1-6 option but it fails as soon as I try and calibrate the Map sensor, see attached error Quote Link to comment Share on other sites More sharing options...
Scott Posted September 26, 2016 Report Share Posted September 26, 2016 Hi Jeff,When using the correct MAP sensor the calibration the MAP reading with key on engine off should be pretty close to your local barometric pressure (BAP).You can see the ECUs current MAP and BAP reading by looking at the General tab of the Runtime Values Window (F12 key to open).Once you have the correct calibration selected you can use the MAP calibration function to get the MAP and BAP matching exactly.Scott. Quote Link to comment Share on other sites More sharing options...
Jeff Hare Posted September 26, 2016 Author Report Share Posted September 26, 2016 Thanks yes the BAP and MAP readings with the car on engine off are within 1kpa so looks like I do have the correct MAP sensor settings. I have taken a log and emailed it in with my tune and description. Thanks. Quote Link to comment Share on other sites More sharing options...
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