MS3 startup and idle when cold
09-30-2016, 04:04 PM
#21
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Also, I got more information about my idle issue that I was having. Basically, it would oscillate up over 2k after driving for a few minutes whenever I put the clutch in. Got to the point where even after 15 minutes of driving, it was still doing it until I left the clutch in or put it in neutral and didn't touch the gas for 10-15 seconds. Then it would settle down and run normally.
I noticed that the oscillation was being cause by the fuel-cut activating at 2k while it was revving up on it's own (once again, in neutral or clutch in, no throttle). So my idle control is revving the car up unnecessarily, but then fuel cut comes in and stops it.
My question is this:
Is there some sort of trigger that needs to be met (condition) to stop the car from trying to idle up? The car is 100% warmed up in this case, but still idling up like it's cold. IF, and this may help, I let the car warm up for 1-2 minutes before driving when first starting it, this issue does NOT take place. But if I crank it over, wait 5-10 seconds, then start driving, happens every time. So in my mind, the MS3 never figures out that the car is done it's warmup even though CLT is in it's happy place (200 or so). WUE and ASE are both not enabled when this condition occurs. The logs I posted way earlier in this thread demonstrate the issue but don't show the fuel cut taking place, which it is.
I noticed that the oscillation was being cause by the fuel-cut activating at 2k while it was revving up on it's own (once again, in neutral or clutch in, no throttle). So my idle control is revving the car up unnecessarily, but then fuel cut comes in and stops it.
My question is this:
Is there some sort of trigger that needs to be met (condition) to stop the car from trying to idle up? The car is 100% warmed up in this case, but still idling up like it's cold. IF, and this may help, I let the car warm up for 1-2 minutes before driving when first starting it, this issue does NOT take place. But if I crank it over, wait 5-10 seconds, then start driving, happens every time. So in my mind, the MS3 never figures out that the car is done it's warmup even though CLT is in it's happy place (200 or so). WUE and ASE are both not enabled when this condition occurs. The logs I posted way earlier in this thread demonstrate the issue but don't show the fuel cut taking place, which it is.
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09-30-2016, 08:38 PM
#22
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I believe I have the exact same issue and that it is the same one mentioned here: https://www.miataturbo.net/megasquir...ng-idle-87616/ . As you mentioned, when the car is cold, it will go to the proper target closed loop idle target for the corresponding CLT. However, as the car is warming up, the Closed Loop Idle Target keeps jumping up by 300-400RPM every time the car is placed into neutral. Then, you have to wait 5-10 seconds in neutral for the Closed Loop Idle Target to ramp down to the desired 850RPM for CLT > 180degrees (or whatever the corresponding RPM for your current CLT is).
If you encounter a lot of stop signs on the way to your destination (like I do to work), the car never sits in neutral long enough for the Closed Loop Idle Target to ramp all the way down to 850RPM. You end up with a Closed Loop Idle Target jumping up 300-400rpm every time you push the clutch in (which results in an idle RPM of ~1800RPM), until you finally sit in neutral long enough for the Closed Loop Idle Target to go down to 850RPM (i.e. the red light outside my work). I took a good log of this happening a few days ago and can upload it if it'll be of help to solving this issue. Sorry I don't have an answer to this yet.
If you encounter a lot of stop signs on the way to your destination (like I do to work), the car never sits in neutral long enough for the Closed Loop Idle Target to ramp all the way down to 850RPM. You end up with a Closed Loop Idle Target jumping up 300-400rpm every time you push the clutch in (which results in an idle RPM of ~1800RPM), until you finally sit in neutral long enough for the Closed Loop Idle Target to go down to 850RPM (i.e. the red light outside my work). I took a good log of this happening a few days ago and can upload it if it'll be of help to solving this issue. Sorry I don't have an answer to this yet.
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10-01-2016, 10:09 AM
#24
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A possible solution on the Enhanced MS3 would be to switch to open loop idle, and then rely on the electrical load idle-up and the power steering idle-up functions of the Enhanced MS3 to compensate for any loads.
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10-04-2016, 07:58 PM
#25
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Unfortunately I have the MS3 Basic but that might be a good solution for OP. I'll have to see if changing the over-run fuel cut RPM has an effect on my problem as well. It's really only a nuisance when the car is warming up but I'm still wondering what actually is going on.
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10-04-2016, 08:34 PM
#27
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Increasing the priming pulse and bumping up my ASE did the trick. Typically it does a crank-sputter-sputter-sputter-die or crank-sputter-sputter-revtothemoon for 5 seconds then settle.
This morning was the first time in months that it fired up normally when cold. I'm happy and will continue to tune.
I wish there was a "A-Z, installing your MS2/3 and getting it to run alright" thread somewhere. The magic "most of our cars need 200-300% ASE" statement I read yesterday on a random thread here was the tidbit I needed to fix my nagging issue.
This morning was the first time in months that it fired up normally when cold. I'm happy and will continue to tune.
I wish there was a "A-Z, installing your MS2/3 and getting it to run alright" thread somewhere. The magic "most of our cars need 200-300% ASE" statement I read yesterday on a random thread here was the tidbit I needed to fix my nagging issue.
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10-06-2016, 01:53 AM
#30
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No.
Another solution that works well for me is to lower the closed loop targets and the PWM idle cranking duty.
Like 1000rpm target from 25-30 onwards, with the cranking duty to match that target + 2%.
Another solution that works well for me is to lower the closed loop targets and the PWM idle cranking duty.
Like 1000rpm target from 25-30 onwards, with the cranking duty to match that target + 2%.
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04-03-2017, 11:03 AM
#31
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To update this thread, I finally did enough reading of dozens of threads to get myself somewhat educated about idle and all the crap that goes along with it.
The oscillation I was seeing was due to the car idling up (even after fully warm), trying to get to a high idle but fuel cut would engage at 1900rpm and then it would start over again. The idle control was using "use last value", not the closed loop idle target table.
If I let the car idle and warm up for 1-2 minutes without driving, the car would drive fine and wouldn't rev up when the clutch was engaged. If I started the car, then began driving normally right away, anytime I'd engage the clutch or put it in neutral, it would rev up to like 2300rpm and stay there for a few seconds at least before starting to drop slowly to normal idle. If I was at a red-light and had to start driving again before the idle dropped all the way to normal hot idle, then it would go right back to the 2300rpm idle every time I was off the gas in neutral or with the clutch in. Because the fuel cut would engage at 1900, the car would just forever be like I was revving the car in neutral. Very aggravating.
I troubleshot this by disabling fuel cut. Once I did that, I noticed that the car would still idle up to 2300rpm or so, but instead of dropping right away then repeating every 2 seconds, it held 2300rpm, then started to back down slowly.
Yesterday, I switched over to from "use last value" to the closed loop idle initial values table. The table was set to all 0's. Set them all to 30 as a starting point (idle valve duty currently between ~14 and 60) and it ran. Idled high once hot, so put those cells at the lower end of my idle valve duty. Seems as though this is the path forward.
I'll be adjusting the closed loop idle initial value table. Does anyone have an example of their own closed loop idle initial value table so I can see what type of changes you make across the table as a baseline?
The oscillation I was seeing was due to the car idling up (even after fully warm), trying to get to a high idle but fuel cut would engage at 1900rpm and then it would start over again. The idle control was using "use last value", not the closed loop idle target table.
If I let the car idle and warm up for 1-2 minutes without driving, the car would drive fine and wouldn't rev up when the clutch was engaged. If I started the car, then began driving normally right away, anytime I'd engage the clutch or put it in neutral, it would rev up to like 2300rpm and stay there for a few seconds at least before starting to drop slowly to normal idle. If I was at a red-light and had to start driving again before the idle dropped all the way to normal hot idle, then it would go right back to the 2300rpm idle every time I was off the gas in neutral or with the clutch in. Because the fuel cut would engage at 1900, the car would just forever be like I was revving the car in neutral. Very aggravating.
I troubleshot this by disabling fuel cut. Once I did that, I noticed that the car would still idle up to 2300rpm or so, but instead of dropping right away then repeating every 2 seconds, it held 2300rpm, then started to back down slowly.
Yesterday, I switched over to from "use last value" to the closed loop idle initial values table. The table was set to all 0's. Set them all to 30 as a starting point (idle valve duty currently between ~14 and 60) and it ran. Idled high once hot, so put those cells at the lower end of my idle valve duty. Seems as though this is the path forward.
I'll be adjusting the closed loop idle initial value table. Does anyone have an example of their own closed loop idle initial value table so I can see what type of changes you make across the table as a baseline?
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