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[ion] C2 · 01-21-2024, 02:52 PM

Link is great. I just haven't learned how to use it fully yet. I shouldn't really have to, as the car should be tuned and ready to rock from the get go, and I just use the software for diagnosis. However, since there is a problem with the existing tune in regards to idle control and very low throttle fueling, I'm trying to learn (when I have time) how to properly adjust everything. I don't want to give my car to the tuner for days/weeks if I can figure it out myself. I'm kind of hesitant after having it gone for almost 3 years.

I've been insanely busy all day every day for work the last 2 months, though, so I just recently started to try to learn what exactly is going on, and I learned a few things. I have the Evans Performance Academy video course for this ECU and they thoroughly explain how to tune everything, so I just need to watch it in detail, and follow the process.

I changed the number of idle air control stepper steps from 310 to 160, and then clamped it 15% - 90% of the max values so it shouldn't ever bottom out in either direction and thus lose its understanding of what percentage it's truly open. I kept having my wife key on/off the car to reset its position as I adjusted the steps and then set percentage open to see how far it moves to find its limits. Originally, I think it would bottom out inadvertently when commanded at high/low percentages, and then it would not actually be where it was commanded from then on.

Now I need to follow the tuning instructions that Evans provides (and perhaps this forum thread: https://forums.linkecu.com/topic/529...eturn-to-idle/) and adjust the actual commanded stepper position values in open loop. Right now just from changing that, it holds the RPM too high when coasting to a stop so that it's still above the lockout RPM of 1800. It seems to command 50% stepper position while driving, and that's too far open after what I changed. Yesterday during my brief first drive after adjusting the min/max percentage and reducing the number of steps from 310 to 160, it was sitting at 2,000 RPM and thus wouldn't enter the state where it starts controlling the idle (until it went under 1800). A couple revs and brief dip under 1800 from engaging the wheels a bit triggered it to start calming itself down to 1,000 RPM.

I could just tell UMS what I found and have them adjust the idle, and the low end fueling. It's definitely way off on idle/coastdown/light throttle as my AFR error is always pegged at -20% (wayyyy too rich, like 10.0 AFR at idle/light throttle/coastdown). So obviously it needs some tuning on the low end. I think it was always unusually rich at idle ever since I got it back in March, but it's gotten worse after fixing vacuum leaks (obviously resulting in more fuel during vacuum conditions), so it definitely needs fuel table tuning. I could probably do this myself like I used to back in the day with HPTuners and AFR error.

My main priority is researching AWD parts and selecting what I need so I can push my fabricator to start working on my other chassis and get that project rolling. Plus nudging UMS about the custom JE pistons that are supposed to be being made so we can get this other engine built and ready to mock up with the AWD setup.

I should finally have some time after this week.

01-21-2024, 02:52 PM	#363
[ion] C2 636 whp Join Date: Aug 2006 Location: AZ Posts: 11,876	Link is great. I just haven't learned how to use it fully yet. I shouldn't really have to, as the car should be tuned and ready to rock from the get go, and I just use the software for diagnosis. However, since there is a problem with the existing tune in regards to idle control and very low throttle fueling, I'm trying to learn (when I have time) how to properly adjust everything. I don't want to give my car to the tuner for days/weeks if I can figure it out myself. I'm kind of hesitant after having it gone for almost 3 years. I've been insanely busy all day every day for work the last 2 months, though, so I just recently started to try to learn what exactly is going on, and I learned a few things. I have the Evans Performance Academy video course for this ECU and they thoroughly explain how to tune everything, so I just need to watch it in detail, and follow the process. I changed the number of idle air control stepper steps from 310 to 160, and then clamped it 15% - 90% of the max values so it shouldn't ever bottom out in either direction and thus lose its understanding of what percentage it's truly open. I kept having my wife key on/off the car to reset its position as I adjusted the steps and then set percentage open to see how far it moves to find its limits. Originally, I think it would bottom out inadvertently when commanded at high/low percentages, and then it would not actually be where it was commanded from then on. Now I need to follow the tuning instructions that Evans provides (and perhaps this forum thread: https://forums.linkecu.com/topic/529...eturn-to-idle/) and adjust the actual commanded stepper position values in open loop. Right now just from changing that, it holds the RPM too high when coasting to a stop so that it's still above the lockout RPM of 1800. It seems to command 50% stepper position while driving, and that's too far open after what I changed. Yesterday during my brief first drive after adjusting the min/max percentage and reducing the number of steps from 310 to 160, it was sitting at 2,000 RPM and thus wouldn't enter the state where it starts controlling the idle (until it went under 1800). A couple revs and brief dip under 1800 from engaging the wheels a bit triggered it to start calming itself down to 1,000 RPM. I could just tell UMS what I found and have them adjust the idle, and the low end fueling. It's definitely way off on idle/coastdown/light throttle as my AFR error is always pegged at -20% (wayyyy too rich, like 10.0 AFR at idle/light throttle/coastdown). So obviously it needs some tuning on the low end. I think it was always unusually rich at idle ever since I got it back in March, but it's gotten worse after fixing vacuum leaks (obviously resulting in more fuel during vacuum conditions), so it definitely needs fuel table tuning. I could probably do this myself like I used to back in the day with HPTuners and AFR error. My main priority is researching AWD parts and selecting what I need so I can push my fabricator to start working on my other chassis and get that project rolling. Plus nudging UMS about the custom JE pistons that are supposed to be being made so we can get this other engine built and ready to mock up with the AWD setup. I should finally have some time after this week.