MEGAsquirt A place to collectively sort out this megasquirt gizmo

Brain MS3X Idle 'Issues' (Idles at 3k)

Thread Tools
 
Search this Thread
 
Old 04-18-2017, 10:59 AM
  #101  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Originally Posted by aidandj
1.4.1 didnt have engine states. They are the backbone of the tune. Used for cl idle, idle ve, idle timing, overrun, etc.

Here is my best guess on how to tune engine states. Waiting on confirmation from Ken. And tuning them myself.

Fast acceleration threshold: Some low gear, step on the throttle. Pick the lowest(?) RPMdot while accelerating. Set the fast acceleration threshold just below that?

Slow acceleration threshold: Datalog idle and see what the highest RPMdot is during idle. Add and remove loads to get rpm changes. Set to just above the highest RPMdot at idle

Fast deceleration threshold: Rev high in neutral and let it drop back to idle. Set it slightly above the highest RPMdot from that test.

Slow deceleration threshold: Same as Slow acceleration threshold, but with negative RPMdot

TPS: Pretty self explanatory, value when tps is closed, and when full throttle

Overrun Map Threshold: Set as high as possible, I usually use a MAP value just under the lowest MAP I see on idle.
Edited my overrun map threshold tuning based on input from Ken.
aidandj is offline  
Old 04-18-2017, 11:04 AM
  #102  
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 15,177
Total Cats: 1,681
Default

I have had VSS not be overly accurate, at least not on an NA with a mechanical sensor. I wouldn't use it for anything except for knowing a rough speed you are going.

​​​​​​​NB might be different and better.
shuiend is offline  
Old 04-18-2017, 12:58 PM
  #103  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Originally Posted by Braineack
i guess since they look at mapdot now, it's fine. we were running into all sorts of issues when they just added vss into the CL idle activation -- mostly high gear, low load cruising.
Right, VSS can now be controlled by speed. So if you enable VSS, the it enables you to select a VSS threshold (MPH). The description for VSS is 'When VSS is enabled for engine states, this setting should be set just above the vehicle speed where idle operation is desired.' and for VSS threshold is 'Use VSS to help get more accurate engine state. Used by Closed-loop idle control.' I think they have them backwards lol.

So if I enable VSS and set speed to say 5 mph, which is what I tried yesterday, it won't kick into idle till I slow down that much. I can see this potentially being an issue in a situation where I'm slamming on the brakes (getting cut off maybe?), so I might raise it to 8 or so. I'm guessing the MS needs like a split second to trigger idle and if the idle valve setting is close enough it should bump right up.

Originally Posted by aidandj
Edited my overrun map threshold tuning based on input from Ken.
I'm going to write down all of those and do a log when I go out tonight. I think the car is working well enough now that I can drive it around, so I'm going to start taking it to school with me so I can take a study break and go tune things instead of reading about them and/or go drive a local loop on the way home to get more data. I'll post the 2 giant logs and tune from last night when I get on my surface so you can check those out and see if there's any info in there that satisfies your curiosity.

Originally Posted by shuiend
I have had VSS not be overly accurate, at least not on an NA with a mechanical sensor. I wouldn't use it for anything except for knowing a rough speed you are going.

NB might be different and better.
I think 1.5 may circumvent this issue by only triggering VSS below a certain speed.

Unrelated to anything, if virtual dyno is smart enough to use the best pull in a large log, then apparently I'm sitting at 110ish whp and 100 wtq. Lulzzzzz. My goals for the turbo setup are to double the stock hp. I think I'll be able to do that and keep my stock engine happy hahaha.
I still haven't deleted/modified the stock air intake so I'm guessing things could be a lot better than they are. Also fueling needs to be optimized a bit. I feel like I should be seeing a higher number right now though. I also used 2450 as the weight which might be like 200 lbs low because my gas tank is full, the car has a roll bar + heavy wheels + donut, and I weigh like 170. I'm curious what the 'actual' weight is closer to... I think the stock 2000 weighs like 2332 or so, but I'm guessing that's without a full tank of gas.

Edit: I think the 2332 weight is the curb weight that includes all fluids etc for the nb1. I guess I just need to add like 200lbs for myself and the roll bar.

Last edited by ridethecliche; 04-18-2017 at 01:35 PM.
ridethecliche is offline  
Old 04-18-2017, 02:02 PM
  #104  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

So if I enable VSS and set speed to say 5 mph, which is what I tried yesterday, it won't kick into idle till I slow down that much. I can see this potentially being an issue in a situation where I'm slamming on the brakes (getting cut off maybe?), so I might raise it to 8 or so. I'm guessing the MS needs like a split second to trigger idle and if the idle valve setting is close enough it should bump right up.
i want to be able to idle at 80mph. im not kidding.


also, VSS stands for: vehicle speed sensor. Your terms are killing me

only triggering VSS below a certain speed.
youre using your VSS to tell the MS how fast youre traveling.
Braineack is offline  
Old 04-18-2017, 02:52 PM
  #105  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Haha, sorry. I'm just going by how MS has it displayed under engine settings to enable VSS for idle/engine states.

Do you just adjust your Idle tables for loads you'd encounter at 80mph? I'm guessing it'd be a cruise load?
ridethecliche is offline  
Old 04-18-2017, 03:23 PM
  #106  
Elite Member
iTrader: (1)
 
sonofthehill's Avatar
 
Join Date: Apr 2014
Location: SF Bay Area, CA
Posts: 3,079
Total Cats: 553
Default

Our idles don't change depending on how fast we are going. Seems like a silly setting, like Brain said I want my car to idle properly regardless of speed.
We tune our tables for every condition our engines encounter.
sonofthehill is offline  
Old 04-18-2017, 04:44 PM
  #107  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

I guess I just don't understand why one would need to idle at 80 miles an hour.

I just drove the car around town for errands without my computer plugged in. Still had a hiccup with the battery light flashing on at low rpms once or twice, but it ran well. I'll do more logging later tonight. For now it's time to go to the library and hide from anyone with BUSM affiliations!
ridethecliche is offline  
Old 04-18-2017, 04:46 PM
  #108  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Its for when you blow your transmission at 80mph. You don't want you engine to die.
aidandj is offline  
Old 04-18-2017, 05:32 PM
  #109  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Originally Posted by aidandj
Its for when you blow your transmission at 80mph. You don't want you engine to die.
Fair enough! I guess it makes sense to have some cells way up there haha.

And I spoke too soon about everything working well lol. Idle dipped low and was hunting real hard on a hot restart. My engine also sounds totally different than what I remember it sounding like. I mayyyy have an exhaust leak from when I moved things around to drill sway bar bolts.
ridethecliche is offline  
Old 04-18-2017, 06:35 PM
  #110  
Senior Member
iTrader: (2)
 
Onyxyth's Avatar
 
Join Date: May 2013
Location: Boyertown, PA
Posts: 735
Total Cats: 62
Default

Originally Posted by ridethecliche
Fair enough! I guess it makes sense to have some cells way up there haha.

And I spoke too soon about everything working well lol. Idle dipped low and was hunting real hard on a hot restart. My engine also sounds totally different than what I remember it sounding like. I mayyyy have an exhaust leak from when I moved things around to drill sway bar bolts.
Flatten your air density table

edit: nvm! I see you already did
Onyxyth is offline  
Old 04-19-2017, 02:01 AM
  #111  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Originally Posted by aidandj
1.4.1 didnt have engine states. They are the backbone of the tune. Used for cl idle, idle ve, idle timing, overrun, etc.

Here is my best guess on how to tune engine states. Waiting on confirmation from Ken. And tuning them myself.

Fast acceleration threshold: Some low gear, step on the throttle. Pick the lowest(?) RPMdot while accelerating. Set the fast acceleration threshold just below that?

Slow acceleration threshold: Datalog idle and see what the highest RPMdot is during idle. Add and remove loads to get rpm changes. Set to just above the highest RPMdot at idle

Fast deceleration threshold: Rev high in neutral and let it drop back to idle. Set it slightly above the highest RPMdot from that test.

Slow deceleration threshold: Same as Slow acceleration threshold, but with negative RPMdot

TPS: Pretty self explanatory, value when tps is closed, and when full throttle

Overrun Map Threshold: Set as high as possible, I usually use a MAP value just under the lowest MAP I see on idle.
Going to go log these things now. I'll do a mix of things and either take different logs or mark them so I can figure out which is which. I'll post them on here likely tomorrow morning. It's late!

Did the method of testing for overrun MAP change? I.e. is it still supposed to be done by revving up high in a gear and coasting down? Or is it supposed to be done just on idle as above?
ridethecliche is offline  
Old 04-19-2017, 02:15 AM
  #112  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

I edited my post to contain the correct way to tune Overrun Map.
aidandj is offline  
Old 04-19-2017, 08:53 AM
  #113  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

Originally Posted by ridethecliche
Do you just adjust your Idle tables for loads you'd encounter at 80mph? I'm guessing it'd be a cruise load?
have you never had to stop for a redlight, push the clutch, and just put the car in neutral despite traveling over 5mph?

if your code waits for 5mph to engage the idle valve, you have probably already stalled.
Braineack is offline  
Old 04-19-2017, 10:33 AM
  #114  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Originally Posted by Braineack
have you never had to stop for a redlight, push the clutch, and just put the car in neutral despite traveling over 5mph?

if your code waits for 5mph to engage the idle valve, you have probably already stalled.
It doesn't do that though. I'm not arguing with you about the practicality of what you're saying because it makes sense. But last night I put the car in neutral at 20-30 mph and braked to slow down at a light.

I didn't stall. Not once. I did this like 10 times last night. I did get some unwanted idle behavior while completely stopped that I need to figure out. But I have logs for that.
ridethecliche is offline  
Old 04-19-2017, 12:05 PM
  #115  
Retired Mech Design Engr
iTrader: (3)
 
DNMakinson's Avatar
 
Join Date: Jan 2013
Location: Seneca, SC
Posts: 5,009
Total Cats: 857
Default

Still not seeing the advantage to engine states. It also seems to me that to obtain the needed info to set up states, one needs an already tuned car.

And a +1 to idle and speed should be totally independent.
DNMakinson is offline  
Old 04-19-2017, 12:39 PM
  #116  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

Originally Posted by ridethecliche
It doesn't do that though. I'm not arguing with you about the practicality of what you're saying because it makes sense. But last night I put the car in neutral at 20-30 mph and braked to slow down at a light.

I didn't stall. Not once. I did this like 10 times last night. I did get some unwanted idle behavior while completely stopped that I need to figure out. But I have logs for that.
yeah, all im saying is, if activation is only tied to VSS, it's bad. that's a time when it could cause trouble and never engage idle. and if not stall, possible idle droop or very low until you met the thresholds.
Braineack is offline  
Old 04-19-2017, 01:53 PM
  #117  
Elite Member
Thread Starter
iTrader: (2)
 
ridethecliche's Avatar
 
Join Date: Aug 2016
Location: New Fucking Jersey
Posts: 3,890
Total Cats: 143
Default

Originally Posted by DNMakinson
Still not seeing the advantage to engine states. It also seems to me that to obtain the needed info to set up states, one needs an already tuned car.

And a +1 to idle and speed should be totally independent.
Yeah, it certainly seems more complicated than 1.4. I'm still not sure if I should just flash down to 1.4 and start all over with Brain's basemap. It seems like there's much more info I can glean from reading things about that as well. The additional complexity about this has certainly made for a more entertaining start.

Originally Posted by Braineack
yeah, all im saying is, if activation is only tied to VSS, it's bad. that's a time when it could cause trouble and never engage idle. and if not stall, possible idle droop or very low until you met the thresholds.
I can't really comment on that because I really don't know how the code is written, but I'm working on figuring it out. For now the biggest issue was the 3k rpm jump when I was rolling to a stop and that has been 'fixed' for now. I'll likely take it off VSS entirely shortly and try to work on that as well. I was actually getting droop low enough to trigger the battery light but only when I was stopped entirely. I think VEAL might have messed with my idle tables. I might have to go in and see if there's any way to use VEAL without affecting idle values or just do what sonofahill recommended and just tune VE based on logs and fueling from said logs. I can certainly do that as well.

I wonder if the lower temps were messing with things too. I tuned in the 60's the first time and it was in the low 30's last night when I was driving around at 2 AM.

Brain, should I email you or post a video here of the fuel pump priming?
ridethecliche is offline  
Old 04-19-2017, 02:08 PM
  #118  
SADFab Destructive Testing Engineer
iTrader: (5)
 
aidandj's Avatar
 
Join Date: Apr 2014
Location: Beaverton, USA
Posts: 18,642
Total Cats: 1,866
Default

Fuel pump: Check for continuity to ground at the Fuel Pump diagnostic pin. Key off should be not continuous. Then it should go to ground while priming. Then be not grounded a few seconds later.

Bolded text will tell us if its Brain's fault or yours
aidandj is offline  
Old 04-19-2017, 02:46 PM
  #119  
Boost Czar
iTrader: (62)
 
Braineack's Avatar
 
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,501
Total Cats: 4,080
Default

ha.
Braineack is offline  
Old 04-19-2017, 02:47 PM
  #120  
mkturbo.com
iTrader: (24)
 
shuiend's Avatar
 
Join Date: May 2006
Location: Charleston SC
Posts: 15,177
Total Cats: 1,681
Default

Originally Posted by aidandj
Bolded text will tell us if its Brain's fault or yours
​​​​​​​It is never Brain's fault.
shuiend is offline  


Quick Reply: Brain MS3X Idle 'Issues' (Idles at 3k)



All times are GMT -4. The time now is 03:06 AM.