Krystian Posted November 26, 2021 Report Share Posted November 26, 2021 Hello. I have g4x ecu in my lancer evo 8. I purchased this ecu 2 weeks ago. When we try to tune the car the air fuel is changing by itself for no reason. When we tuned it at 14.7 idle and 11.7 full throttle it is running those parameters for 10-20min and than it is running 15.7 idle and 12.5-12.7 full throttle. There is no specific time when this is happening. Sometimes after morning startup running good air fuel than after 20 min running lean, sometimes the other way around. It is happening more often when I turn off the car and start it back on. Please help. Car is running with link iat sensor also. This problem was not happening on my old autronic ecu but the same car setup. I am including 2 loggers showing air fuel difference. thank you PC Datalog - 2021-11-25 8;55;45 pm.llgx PC Datalog - 2021-11-25 9;17;44 pm.llgx Quote Link to comment Share on other sites More sharing options...
Baggy-4G63 Posted November 26, 2021 Report Share Posted November 26, 2021 Tune file?? Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 26, 2021 Author Report Share Posted November 26, 2021 Here is a tune file. e72% 3.pclx Quote Link to comment Share on other sites More sharing options...
Baggy-4G63 Posted November 27, 2021 Report Share Posted November 27, 2021 Would start with looking at your IAT sensor wiring etc. Logs show a value that starts at 3 degrees and goes as low as 1 deg. Surely that's not correct Also if you haven't gone to far with the initial tune i would suggest starting over with fuel equation mode set to "Modelled". Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 27, 2021 Author Report Share Posted November 27, 2021 Thank you for reply. Iat sensor that I have is link iat sensor brand new. I tried different sensor and showing same temperature. Outside temp is minus 5 degree and I have 4 inch thick intercooler and e85 fuel. Tune is all set but I can start over and try modelled. Should I look into that temp sensor still? Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 28, 2021 Author Report Share Posted November 28, 2021 2 more logs from today. Bad air fuel than I stopped the car restart it and it has good air fuel. Very strange problem and link doesn't stand up behind their product and not trying to help. I am just sick with this ecu. When I install old autronic ecu and even stock ecu problem is not there. Fuel pressure is the same on bad and good air fuels. Anyone can help please before I return this ecu to the seller? PC Datalog - 2021-11-27 6;44;59 pm.llgx PC Datalog - 2021-11-27 6;46;38 pm good pull.llgx Quote Link to comment Share on other sites More sharing options...
Ducie54 Posted November 28, 2021 Report Share Posted November 28, 2021 In my quick look you can see the fuel table scaling is very similar from low rpm to high rpm. Why is the master fuel set for 12ms? Why didn't the tuner use modelled mode? Quote Link to comment Share on other sites More sharing options...
essb00 Posted November 28, 2021 Report Share Posted November 28, 2021 The fuel main & fuel table is obviously not yet properly set by your tuner. Even other parameters have not been set. ...so you really can't compare it (yet) with another ECU that has been tuned to your engine. Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 28, 2021 Author Report Share Posted November 28, 2021 Thank you for reply guys. Would those settings cause problems like I have? it is acting like using 2 different fuel maps. Its good but when I restart the car is bad. When I restart the car again is good and so on. The tune was not completed because we run into problems with air fuel when car was restarted. If some of the settings are wrong wouldn't the car run bad all the time? Not only when is restarted? Thanks Quote Link to comment Share on other sites More sharing options...
Ducie54 Posted November 28, 2021 Report Share Posted November 28, 2021 I would strong suggest if your tuning this yourself to visit. https://www.hpacademy.com/ Otherwise find another tuner. essb00 1 Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 28, 2021 Author Report Share Posted November 28, 2021 I was taking classes at hpacademy and dont take me wrong I am far away from professional tuner but When you finish fuel map and you have good air fuel ratio than you turn off the car and start back on and air fuel ratio is 1.0 point leaner it means something is wrong. I took the car to professional tuner w and he started tuning it and when we turn off the car and started back on whole fuel map was running 1.0 point leaner but when you restart it again it is back to normal. My tuner says it is a problem with the ecu. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 28, 2021 Report Share Posted November 28, 2021 Have you compared injector duty cycles/pulse widths at similar points in the fuel map when it is having issues to when it isn't? or alternatively do you have logs of both? If it is running rich at one point and lean at another you really want to know if you are giving it the same amount of fuel or if the airflow has changed. Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 28, 2021 Report Share Posted November 28, 2021 For everyones elses benifit, I have tried helping this user for several days last week via the tech support ticket system. If you overlay a "good run" with a "bad run" and line up a point where the RPM & MAP is the same, you can see the injector PW is also the same. RPM & MAP is a good indicator of air flow. So, we can say the airflow is the same, the ECU is commanding the same injector PW, if air and fuel flow is the same, the result should be the same AFR. The fact it is different would suggest some external influence or injector behavior that is not repeatable. For this reason I have suggested the first thing he needs to do is fit a fuel pressure senor and verify the IAT calibration is correct (since this seems very low). Overlayed logs below. Coloured traces are a good run, pink traces are the lean run. dx4picco 1 Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 28, 2021 Report Share Posted November 28, 2021 I've actually thought of another thing to check, the Lambda input is an analog voltage so what controller is being used and does it have a sensor ground reference? Quote Link to comment Share on other sites More sharing options...
kaptainballistik Posted November 28, 2021 Report Share Posted November 28, 2021 17 minutes ago, Vaughan said: I've actually thought of another thing to check, the Lambda input is an analog voltage so what controllers are being used and do they have a sensor ground reference? If its an Autronic O2 controller it will take the sensor ground/Power from the ECU.. from memory (Its been awhile), I'm not sure how well it would play with a Link. 1 hour ago, Krystian said: I was taking classes at hpacademy and dont take me wrong I am far away from professional tuner but When you finish fuel map and you have good air fuel ratio than you turn off the car and start back on and air fuel ratio is 1.0 point leaner it means something is wrong. I took the car to professional tuner w and he started tuning it and when we turn off the car and started back on whole fuel map was running 1.0 point leaner but when you restart it again it is back to normal. My tuner says it is a problem with the ecu. Coming from a Diehard Autronic user standpoint, You need to be careful of the related tables, Takes a little bit of time but once you figure out what does what the ECU is much easier to understand... Just takes some reprogramming of the old headspace! Can I ask what O2 controller you have, and how far the O2 sensor is from the turbo? and.... do you have a Exhaust gas temp sensor? I did manage to get my Autronic IAT sensor to work, just took some mucking about! Quote Link to comment Share on other sites More sharing options...
JOEL Posted November 28, 2021 Report Share Posted November 28, 2021 We had this same problem in my brothers EG Civic, thought the fuel pump might be dying, opened the tank, and it was full of rust/corrosion. Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 28, 2021 Author Report Share Posted November 28, 2021 21 minutes ago, JOEL said: We had this same problem in my brothers EG Civic, thought the fuel pump might be dying, opened the tank, and it was full of rust/corrosion. When I install my autronic ecu back to the car problem is not there. I also opened my fuel pumps and no rust or corrosion there. It has steady fuel pressure no drops. Good vs bad air fuel happened when car is turn off than back on on link ecu 1 hour ago, kaptainballistik said: If its an Autronic O2 controller it will take the sensor ground/Power from the ECU.. from memory (Its been awhile), I'm not sure how well it would play with a Link. Coming from a Diehard Autronic user standpoint, You need to be careful of the related tables, Takes a little bit of time but once you figure out what does what the ECU is much easier to understand... Just takes some reprogramming of the old headspace! Can I ask what O2 controller you have, and how far the O2 sensor is from the turbo? and.... do you have a Exhaust gas temp sensor? I did manage to get my Autronic IAT sensor to work, just took some mucking about! I am using aem wideband with link ecu. I am using link iat sensor. No exhaust temp sensor. 1 hour ago, Vaughan said: I've actually thought of another thing to check, the Lambda input is an analog voltage so what controller is being used and does it have a sensor ground reference? I am using aem wideband connected to the link ecu. I also have another wideband gauge in car so 2 air fuel gauges with brand new sensors in car showing same air fuel. But when car is restarted both showing lean air fuel JOEL 1 Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 28, 2021 Author Report Share Posted November 28, 2021 1 hour ago, Adamw said: For everyones elses benifit, I have tried helping this user for several days last week via the tech support ticket system. If you overlay a "good run" with a "bad run" and line up a point where the RPM & MAP is the same, you can see the injector PW is also the same. RPM & MAP is a good indicator of air flow. So, we can say the airflow is the same, the ECU is commanding the same injector PW, if air and fuel flow is the same, the result should be the same AFR. The fact it is different would suggest some external influence or injector behavior that is not repeatable. For this reason I have suggested the first thing he needs to do is fit a fuel pressure senor and verify the IAT calibration is correct (since this seems very low). Overlayed logs below. Coloured traces are a good run, pink traces are the lean run. Hello Adam. Iat sensor I am using is link iat sensor . when iat sensor showing 9c and I restart the car and it is still showing 9c but 1.0 point leaner air fuel it means iat has nothing to do about it. Am I understand it correct? I would understand when iat temperature would be different on both logs it means maybe iat fuel correction its in the game. I can fit fuel pressure sensor in but again why would it have pressure problem when even on idle car showing different air fuel and same fuel pressure. When I start the car and its showing 14,7 air fuel idle and 38psi fuel pressure than I shut the car off and start back in and showing 15.2-15.3 on idle and still 38psi pressure it means pressure is working just fine. Also when I switch ecu to autronic or stock ecu fuel pressure is fine also. I was running this car on 45psi boost with those fuel pumps and autronic ecu week ago so I highly disagree there is a fuel pressure problem. Also voltage by pump is the same on lean and normal air fuel around 13.7V. Thank you for all your help Adam I really appreciate that! I will most likely install fuel pressure sensor to be sure. I spoke with another gentlemen from link support today and he says that it is strong possibility that ecu is playing up and it will need firmware update ( I do have latest update now) so he advise me to test injectors with the scope and give him an update. Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 29, 2021 Report Share Posted November 29, 2021 6 minutes ago, Krystian said: Hello Adam. Iat sensor I am using is link iat sensor . when iat sensor showing 9c and I restart the car and it is still showing 9c but 1.0 point leaner air fuel it means iat has nothing to do about it. Am I understand it correct? I would understand when iat temperature would be different on both logs it means maybe iat fuel correction its in the game. How about if air temp had changed but the sensor was showing the temp was the same? In one of your logs the IAT showed 1degC at 280kpa which is why I suggested you should validate it. It is a pretty simple test to dip the sensor in a cup of ice water and a cup of boiling water to confirm. 8 minutes ago, Krystian said: I can fit fuel pressure sensor in but again why would it have pressure problem when even on idle car showing different air fuel and same fuel pressure. Because it is not fuel pressure that matters - you need to know what differential pressure is - this is the difference in pressure between the top of the injector and the bottom of the injector. Looking at a gauge on the regulator only gives you half the picture. Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 29, 2021 Report Share Posted November 29, 2021 6 minutes ago, Adamw said: Looking at a gauge on the regulator only gives you half the picture Also the visible resolution of those gauges tends to be fairly average. Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 29, 2021 Author Report Share Posted November 29, 2021 42 minutes ago, Adamw said: How about if air temp had changed but the sensor was showing the temp was the same? In one of your logs the IAT showed 1degC at 280kpa which is why I suggested you should validate it. It is a pretty simple test to dip the sensor in a cup of ice water and a cup of boiling water to confirm. Because it is not fuel pressure that matters - you need to know what differential pressure is - this is the difference in pressure between the top of the injector and the bottom of the injector. Looking at a gauge on the regulator only gives you half the picture. Iat sensor showing 20c in my heated garage so it look like it is working. I do agree with you about fuel pressure I will install pressure sensor anyway. I did one more test. I don't have scope in my garage but I did start the car and air fuel was lean (bad) and I measured injectors Mv with my voltometer. On bad (lean 15.5) air fuel idle car warm Mv was 105 than I shut off the car and restart it and this time air fuel was good 14.7 and mv was 115. But when I looked at laptop both bad and good air fuel had very similar Injector ms. It does mean that the pulse width has changed right? Why? Quote Link to comment Share on other sites More sharing options...
Vaughan Posted November 29, 2021 Report Share Posted November 29, 2021 measuring the injector voltage with a multimeter won't give you the pulse width, you need an oscilloscope for that. You could measure the voltage of the injector supply though to see if the power supply to the injectors is inconsistent. A different power supply voltage means a different deadtime and if this different deadtime isn't accounted for this means a different volume of fuel injected. Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 29, 2021 Author Report Share Posted November 29, 2021 5 minutes ago, Vaughan said: measuring the injector voltage with a multimeter won't give you the pulse width, you need an oscilloscope for that. You could measure the voltage of the injector supply though to see if the power supply to the injectors is inconsistent. A different power supply voltage means a different deadtime and if this different deadtime isn't accounted for this means a different volume of fuel injected. I know I need oscilloscope for that but I dont have one in my garage. I measured mv on the cable that going to injector. On bad air fuel is 105mv on restart and good air fuel is 115mv but laptop showing similar injectors ms also car had same idle rpm but mv at injector wires was different Quote Link to comment Share on other sites More sharing options...
essb00 Posted November 29, 2021 Report Share Posted November 29, 2021 I'm just wondering, what's the location of the IAT sensor? From idle/vacuum all the way to 280kPa, IAT reading remains constant? Quote Link to comment Share on other sites More sharing options...
Krystian Posted November 29, 2021 Author Report Share Posted November 29, 2021 1 hour ago, essb00 said: I'm just wondering, what's the location of the IAT sensor? From idle/vacuum all the way to 280kPa, IAT reading remains constant? It is located in the intercooler pipe in the middle between intercooler and throttle body. Typical evo 8 location. When I tried different sensor it does show similar results. It has big turbo on low boost at this moment. Has 4 inch thick intercooler and I am using e85 fuel Quote Link to comment Share on other sites More sharing options...
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