Quick question about idle tuning
#21
I think your "Idle up duty adder" is waaay too high at 14%. So when you turn on the AC you get idle to jump up a lot. Not too bad. But then CL turns the IAC valve back down. And now, when you turn of AC, we take 14% away from the IAC value and the engine stalls. Lower that to maybe 3% or so and see if that fixes it.
Like I said, I have no problems when the A/C comes ON. All that works pretty smoothly considering I spent not a lot of tuning time on that. The adder is enough so it doesn't crawl up to target rpm, it might be possible to make it lower, but it's only going to be something like 2%, it's pretty close I think.
Also I've noticed that the ac up delay doesn't kick up the RPM's until it sends the AC out, it doesn't "get ready" 300ms before, it just delays the activation.
#24
Switch goes into MS, MS sends AC UP to A/C. But the switch in the A/C system overrides the A/C switch on the dash, which allows the MS to cycle the A/C when necesary. I might be wrong on that last statement, but I'm getting closer to fixing this.
What did it was the RPMdot activation/deactivation values.
I had the activation value too high I think, It's a very confusing value to me, but I changed this:
From 250 to 30 as I saw in a blog post and it seems like it's ALMOST perfect, it's pretty smooth considering the **** it was yesterday.
I still wouldn't be able to explain the setting to a 5 year old so I would appreciate it if someone explained what that one combined with the RPMdot in the delay settings do when the **** goes up and down. I would've believed that the RPM change had to be LOWER than 30 for the closed loop to activate, but perhaps it means it has to be AT LEAST that? cunfusing
The positive side is that I drove in heavy traffic with the A/C on, I tried to stall it doing all the stuff that would've done it yesterday and it only tried to stall once and it was outside these two on/off events, I have a log of that so hopefully I can understand what happened. Mostly, a decent drive.
What did it was the RPMdot activation/deactivation values.
I had the activation value too high I think, It's a very confusing value to me, but I changed this:
From 250 to 30 as I saw in a blog post and it seems like it's ALMOST perfect, it's pretty smooth considering the **** it was yesterday.
I still wouldn't be able to explain the setting to a 5 year old so I would appreciate it if someone explained what that one combined with the RPMdot in the delay settings do when the **** goes up and down. I would've believed that the RPM change had to be LOWER than 30 for the closed loop to activate, but perhaps it means it has to be AT LEAST that? cunfusing
The positive side is that I drove in heavy traffic with the A/C on, I tried to stall it doing all the stuff that would've done it yesterday and it only tried to stall once and it was outside these two on/off events, I have a log of that so hopefully I can understand what happened. Mostly, a decent drive.
#25
Retired Mech Design Engr
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Coming into idle from, say 1600 + RPM, once the TPS goes below setting (your 3% is a bit high) the IAC is opened to the value of (DC in the target table PLUS the Dashpot PLUS fan adder PLUS A/C adder [if fan or A/C are on]). That value of DC should be enough to stabilize RPM at a value ABOVE your idle target. Note word "stabilize". That means a LOW RPMDot. Then, if also MAP is above your 25kPa trailing throttle value, CL idle PID will engage and begin controlling idle, usually driving it down to your target RPM.
DNM
DNM
#26
How would that change if my RPMdot was 250? It wouldn't try to stabilize unless the change is bigger than that, or it would try to stabilize until the change is bigger than that? I'm trying to understand why the IAC control was like "well I'm out" until it was too late and then it was like "oh damn, the idle took a ****!" Now it's more like "oh used we are going down, ok let me help" and the landing is soft.
Thanks for the explanation though, I understand better overall
Thanks for the explanation though, I understand better overall
#27
Retired Mech Design Engr
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I don't know why that setting would affect A/C idle-up. Mine is set at 90. I can't remember why. On the other one, the PID Disable, I never did figure that one out, so it is set at 1000 to not ever come into play.
I do have a general question about the log you posted above: Do you know why it does not show any AFR readings?
I do have a general question about the log you posted above: Do you know why it does not show any AFR readings?