TJaruzel

1.6 Miata on a Ms3 Basic with 640cc injectors from flow force. There has always been one problem with my tune. Basically, Ill set my afr in the VE table cells I idle in, usually to around a 14.3 because that is where it is happy. Then Ill drive around some, hit a red light and my idle afr will be a 13.7. I figured maybe it is my air density table but most of the time the temp isn't moving but a couple degrees between the time my afr has gotten richer. Also, this seems to only really affect idle, My wot afrs really don't change between the lights where my idle goes from 14.3 to 13.7. Anyone have any ideas? I'm running closed loop idle. Don't have any logs right this second, but can get some.

matrussell122

iTrader: (1)

For us to help we really need the tune file at the very least. Also logs help a ton. When you take the lok ad markers to points at the light where the issue is

rwyatt365

Start here ^^^

Basic questions (from me) would be;
- Does the AFR at idle ever go back to 14.3?
- Are you using CL Idle?
- What's your "ramp to target" time?

Too many "What if's" to diagnose.

curly

iTrader: (25)

If you're not in the 12s or 15s, I'd say you're doing something right. You're barely half a point from your 14.3 target. What are you concerned about?

TJaruzel

Yes, obviously neither afrs it reaches are dangerous so I guess I shouldn't care but as it is my daily, I just find it annoying because I feel it shouldn't be different if in the same cells it was minutes ago... Here is the tune file for now, will go capture some logs later today. Yes, the afr does seem to make its way back to 14.3 if it is idling for a while but that is actually due to my density table pulling fuel out. I have watched intake temps go up decent enough to make that impact. As you will see in the file, I am using closed loop, and the ramp to target time is 1 second.

curly

iTrader: (25)

One of two things is happening. You're either getting more fuel, or less air. We really need to see a log to figure out what is happening. But look for a decrease in your idle valve duty cycle, an increase in your injector duty cycle, or a change in enrichment percentage. You want to look at total correction, and if it's higher when you're at 13.7afr, you then need to find if it's WUE, ASE, EGO, etc.

TJaruzel

I guess sometimes I would stop and see my idle valve was more open now that I have figeted around with stuff and it would be more lean. I guess my question now is what causes the same idle rpm to be at different idle valve percentages. Causing the idle to be leaner or richer even with the same ve cells. Here are 2 logs where I guess you can get an idea. Log 1 is where my idle is fairly constant 14.6-14.7 then I drive and stop and it starts at a 14 then works its way around relatively back. But I have also had it lean out and its because the idle valve is open more with the same fuel. How would I go about stopping this?

TJaruzel

I have definitely noticed a pattern over time of paying close attention still trying to reduce the changes in afr from idling. Cruising through traffic hitting red lights my idle valve will usually be some were around 29% at a red light and keep my afr right at a 14.3 which is where I want. Although, I may go park in a spot and idle for like 5 minutes and my idle valve starts to creep open more usually around 32%. This is what causes the leaning out, because obviously it is commanding the same fuel in my ve table each time. The afr will creep up to a 14.7-14.8 when sitting around idling for a bit. Definitely not my Air temps, because they are fairly consistent during my testing, and I have my MAT table tuned pretty well. Now you may ask why I care, well when it leans out to a 14.8 it will get slight idle stumbles, maybe this would be solved by going sequential, but I would rather try solving why closed loop is having to open my idle valve more sometimes just to hold the same rpm for now. Is this possibly due to me not having my idle valve plumbed into my intake piping? Right now I just run a small filter on it

curly

iTrader: (25)

TJaruzel

I keep timing at 16 degrees at idle, and it does not change during the afr change. Rpm stays very consistent at 900. I don't run ego correction until above 1300 rpm so yea it is doing nothing. I guess I could just lower that down so it corrects it. Never thought about it, will test tomorrow.

curly

iTrader: (25)

TJaruzel

Lowered the rpm threshold for ego, quickly realized having it on the simple algorithm was not going to cut it. Oscillated too much around the afr. So I changed it to PID and messed with the settings for a while and I must say it does compensate well, but still likes to oscillate around a 14.3 cause it is trying to correct for every little difference. I'm happy with it though