thebigtuna

Hey guys,

So I've owned my miata for about a year and have been tuning myself on a MS3 for a while now. It's been going well and I have learned a lot but I've really struggled as of recent in trying to tune Closed Loop. I've gotten most things how I want them but now I've been getting this weird osscilation that I can't fix. I recently switched from 87 to 91 before boosting here in the next months when I get my Mkturbo kit in. I retuned my VE table, WE and ASE which I thought I had dialed again but I guess not. My issues have been a hanging idle at like 1500 after driving shortly after starting, which could be fixed by sitting still for a bit till it gets all warmed up and then going. Is there a better fix? Adjusting my WE seemed to help I suppose. The main issue is in the data log I have attached. There is a weird ossicliation that I believe is linked to that advanced part of the CL idle. I tried adjusting some things to get rid of the weird hanging idle and fix a droop that happens when I hold both of my power window switches. I'm a noob but would love to learn if you all know of a thread that would be good or can explain it to me. I've tried reading a miata blog? about a guy explain CL idle but was left with more questions and confusion. Thanks in advance. Please don't flame too hard

Edit: More info, 96 miata. Stock everything but soon to be boosted. Stock maf without using the provided one with the Megasquirt (Could that be causing issues with my idle?). Recently my AEM Uego has been reading off by about .5 too low. My head hurts

Akina_Downhill

iTrader: (1)

What do you mean about using the maf provided with megasquirt? You have maf off anyway.
Tune your idle cells first, then tune your closed loop idle.

matrussell122

iTrader: (1)

As Brianeak would say "tune and search"

I went through this just the other day. Search about tuning idle theres lots of threads on it. Start in warmup mode then go to CL if needed. You need to have your idle ve table and spark dialed in first. Also are you running AC/Power Steering?

thebigtuna

Thanks for the replies. I understand I need to tune idle first, it's been tuned for a while but I'm working on fine tuning which created the problem. I guess the maf question was dumb just throwing out idea as to what I could be doing wrong. Ve table has been tuned for a while. I don't want to touch the spark right now as I don't want knock and am unsure about my skills doing that right now. No A/C or PS.

matrussell122

iTrader: (1)

if i recall 10-15 decrees in the idle cells is optimum under 35kpa and up to 1350rpm

matrussell122

iTrader: (1)

also really do search there is a thread on here where brian has a step by step for CL idle. Ill post a screenshot of my idle when i get home its not fully tuned im at 1100rpm but by the end of the night ill have it idling at 800-900 which is where i like it

thebigtuna

Okay I'll try to do a better search and see what I find. Maybe it's not my CL idle. When I'm fully warmed up I idle at 800-900 but get a weird hanging idle for about 5 seconds or so at like 1200. I posted a datalog and tune so someone might be able to see what my problem is and help me. It's a weird osscilation that's kind of just started

thebigtuna

Is this the thread you were referencing?
https://www.miataturbo.net/megasquirt-18/idle-tuning-instructions-sticky-request-59027/

If so I feel like an idiot because it took me 10 seconds to find it in google. It seems my understanding of idle tuning was way off from what actually needs to happen so I apologize for this thread. Thanks for helping me realize this guys. Off to read and practice tuning more

matrussell122

iTrader: (1)

Thats the one

vitamin j

iTrader: (5)

Firstly, do you understand the idle target table how it drops from a high idle at cold temperatures to the normal operating idle once fully warmed up?

Secondly, the rev hang is because you CL idle target table is not tuned good enough, the computer picks the value from the table first before using CL to dial it in. The more accurate you get the table, the more accurate the idle will be. You will also want to check all of the requirements to enter CL and make sure they are good values, going into and out of CL can cause oscillations.

thebigtuna

Yeah I think I have a decent grasp on the CL idle target values. I think I have most of mine set to about 1000 till it gets to warm it gradually goes to 800. Is there a benefit to having it stay higher? To me it's just annoying to hear the engine revving louder than I'd really like which is why I chose a compromise of 1000.

The second part makes sense for my problem. I had never set up or even really known about the seperate Idle VE table. Thought idle ve was just the 4 or so cells it hung at in the normal VE. I recently found a post by y8s? Detailing how to dial in that table which I hope to do in the coming days. As well as the braineak one mentioned earlier in the thread

Akina_Downhill

iTrader: (1)

Your IAC valve frequency is high for a na valve.Try ~200Hz
The rpm hang is most likely cl idle algorithm not kicking in(conditions not met), plus you are using "use last value" and not an initial value table.
Initial value table is what vitamin_j told you to tune actually.
You can get the car to idle like a charm under any conditions if you get the grasp of it, follow the link posted above.

thebigtuna

Thanks for the help guys. I didn't even know closed loop idle initial values table was a thing. I can get close with those values by knowing my minimum I gained from doing the IAC valve test a while back to get my closed loop minimum duty? I'm learning a whole lot of new things I had been overlooking. If I'm understanding right this in the thread above Brain is discussing tuning closed loop idle PID and then later on the Idle VE. Which was also talked about by y8s in another thread I found. I also changed the PMW Idle frequency to 204 hz which should be better? I attempted to do Brain's CL PID but couldn't get the idle to hang at any rpm and then back it down by increasing I. I'm guessing that is because my Idle VE table and General Spark table have just big jumps in numbers? I've tried smoothing out the Spark a little in the idle regions and Tuning the Idle VE table but haven't gotten back out to the car to see if it helped. I don't have AC so it was kind of hard to get the car under load like he talks about. Also should I be using PID or normal activation for Idle VE? Normal so I can control the parameters correct?

matrussell122

iTrader: (1)

I just redid my clbidle last night and for me it works good. I'll post a screenshot of my setting when I get home but this is what I did.

1. Set spark cells the same and tune idle be table for the most vacuum I got 32kpa
2. Setup cl parameters and the initial value table
3. Then I followed Brian's steps and for our when I switched from basic to advanced I left it alone because it worked good.

You can see my general setting on my build now but I still did 5min of tuning after to get dialed in really good

thebigtuna

As soon as I set it to basic my rpm go haywire and i can't tune anything. It's just jumping around everywhere. Is that my parameters ******* something up. I was trying to do those steps basically to tune idle ve and the initial values but couldn't get anything done. Doing brains steps wouldn't work as the idle would never hang for me. Just dropped immediately as I turned things off or if I left my a/C on it would stat at 2k and wouldn't drop np matter how much I % I put in

matrussell122

iTrader: (1)

mine didnt hang either i dont think its a big issue if it doesnt especially with all the updates since brians thread. Post current tune and ill check it out tonight

thebigtuna

Okay I'll get it off my laptop when I get off work. Thanks so much. How did you tune interval if you couldn't get it to hang and increase it as it dropped to the idle you wanted?

thebigtuna

So here is the "updated tune". Check it out please as I'm sure I overlooked something basic but I tried to take in all the advice. Is it normal for my rpm dot to only be at a max 30 at idle and kpa around 35-40?. Might have been the higher idle rpm I'm not sure.

matrussell122

iTrader: (1)

just for ***** copy my cl idle settings and see what it does

matrussell122

iTrader: (1)

idle curve is no bueno at the last point i have mine set to go from 1500 cold to 900 warm, sensitivity is way high, rpm dot is way high, set it to basic mode first before advanced, close delay of 1

i set my sensitivity around 1000 and works good but have yet to dial in really good