Mindfreakattack Posted August 17, 2021 Report Share Posted August 17, 2021 Good day all, i kind of sorted out my idle with the closed loop. However, when i went driving around the neighbourhood, i noticed the car dropped too much in RPM everytime i clutch in to decel. My log says "Crank % DC" during this period. and im guesing the Idle position might had been the cause of this drop in RPM. May i know where can i adjust this crank DC? *Note this only happens in with A/C on. With the AC off, the rpm doesnt drop as much. Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 17, 2021 Report Share Posted August 17, 2021 That old firmware had a bug which caused idle status to be reported incorrectly in some cases. Update your firmware to fix that. But it is not the cause of your idle problem - just the status is reported incorrectly. It doesnt look like idle control has been tuned at all. 4 things to improve: Your base position table hasnt been tuned, you can see it needs 36%DC to idle when warm, but you only have 18% in your base position table. You have no speed lockout assigned, this means when you are in overrun the closed loop is winding the idle valve closed trying to bring RPM down to target, then when you push in the clutch and release the drive the valve is too closed to catch the falling RPM. RPM lockout is too high. This causes a similar problem to #2, the valve starts closing earlier than it should. Normal RPM lockout is around 400RPM. There is no idle ignition control, this generally improves the ecu's ability to quickly increase torque in a potential stall situation. Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 17, 2021 Author Report Share Posted August 17, 2021 Okie.. thank you very much for the reply.. noted all ur kind pointers.. will continue to work on those Im actually still learning the rope.. Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 17, 2021 Author Report Share Posted August 17, 2021 May i also clarify, my Idle position was set to 18 for 80Deg ECT, because that number (18) gave me idle rpm i wanted on the rpm target. The 35 you saw on the idle position during warm was with me having the AC switched on. Which i had the AC stepper set to 15 to achieve my rpm target. Does this make sense to you? or am i missing something off the formulae Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 17, 2021 Report Share Posted August 17, 2021 Yeah you have the logic right. But it still looks like base is too low to me. Would need to see a log with both AC on and off and fans on and off when hot, But it looks to me like the base needs to be a few % higher, probably AC step needs to be a bit smaller and there possibly needs to be more fan step. But make the other suggested changes and see how it looks. Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 18, 2021 Author Report Share Posted August 18, 2021 So i updated the map with 400rpm lockout and enabled speed lockout. Now the car doesnt drop as much in rpm during decel am very grateful for ur guidance. I am gonna activate the idle ignition control next.. hoping to fine tune the rpm for idle Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 18, 2021 Author Report Share Posted August 18, 2021 HI AdamW, may i ask why do we want to do open loop tune for the idle from cold to normal operating temp, before we tune the Closed loop from cold to normal operating temp again. From what i see, the Open loop or Closed loop shares the exact same Base Idle position map. Which mean when i do my tune for closed loop, i am actually changing the value i did for my open loop. doesnt that defeat the purpose of me doing open loop tune? Quote Link to comment Share on other sites More sharing options...
dx4picco Posted August 18, 2021 Report Share Posted August 18, 2021 Because in closed loop everything is compensated live, throttle position interact with igntition timing. You do not want to rely on the computer compensating for you. Yes you are right the table is the same. Because closed loop uses the base values that we call open loop. You must think like, I tune open loop and once everything runs fine I turn on closed loop to compensate/correct for small variation due to temps, humidity, elevation etc. Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 18, 2021 Author Report Share Posted August 18, 2021 58 minutes ago, dx4picco said: Because in closed loop everything is compensated live, throttle position interact with igntition timing. You do not want to rely on the computer compensating for you. Yes you are right the table is the same. Because closed loop uses the base values that we call open loop. You must think like, I tune open loop and once everything runs fine I turn on closed loop to compensate/correct for small variation due to temps, humidity, elevation etc. Okie... thank you very much for the sharing Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted August 19, 2021 Author Report Share Posted August 19, 2021 Hi guys, so i reattempted to tune my idle ISC for open loop, followed by Closed Loop (both starting from cold engine). I keep having to reduce the base idle position to values well below 30% with the AC off. The car drives perfectly fine with the AC switched off. after i applied the advise given by Adam earlier on the 4 pointers, i kind of have car idle and drive (decel) MUCH better, but only with the AC off. I did a couple of trial and errors, and concluded on my end that the only way to get the car get back to idle target rpm nicely without too much dip, or any rpm hunting is to have almost 25% AC Step set. Anyone has any idea why is this the case? Attached is my current tune files, and log file of me on warm idle with AC off and AC on, each with 3 x free rev, note how the RPM dip below target RPM with the AC on. Quote Link to comment Share on other sites More sharing options...
Adamw Posted August 19, 2021 Report Share Posted August 19, 2021 Update to the latest firmware - you are on 5.6.5 which is about 4 years old. Load this tune and give us a new log. Could do with lambda too to see what is going on there but see if this helps. Aconandoffwarmtune adams changes.pclr Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted November 22, 2021 Author Report Share Posted November 22, 2021 Hi Adam, So i redid the throttle body adjustment and tuned the cold to warm idle. Still observe drop in RPM during AC clutch engagement. Any further advise? i guess something worth mentioning is that when the engine is still relatively cold (40-50deg ECT), the rpm doesnt drop so drastically till almost stalling. Is it because at that point of time, the idle target rpm is still at 1300, thus the AC load cant drag it down much? Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 22, 2021 Report Share Posted November 22, 2021 Change the idle ignition MAP lockout to 75kpa, Change the AC clutch delay to 0.2s. I woul also change the idle ign table to be something like below. Then do a new log but leave the AC on and off for longer so we can see how much step it needs. Quote Link to comment Share on other sites More sharing options...
Mindfreakattack Posted November 23, 2021 Author Report Share Posted November 23, 2021 Hi Adam, as per your suggestion. However, unfortunately i didnt notice much difference 24nov tune.pclr Quote Link to comment Share on other sites More sharing options...
Adamw Posted November 23, 2021 Report Share Posted November 23, 2021 Increase all cells in the AC step table to about 12% and increase the AC clutch delay, try around 0.5sec. Quote Link to comment Share on other sites More sharing options...
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