Slo_crx1

iTrader: (9)

Currently I have the jitter fix #2 on the car as that seemed to run the best for me. My MAP VE is not a strict 1:1 ratio, rather I found it was never quite exactly on through the whole rpm range and any time I ever made any adjustments to it I would get odd "rich spots" in certain portions of my fuel map for no apparent reason (like 10:1afr's during a cruise situation that 200rpm more would clear out to the normal 14.7).
On the other hand I don't have any of the typical lean conditions when first starting the car cold. On the contrary, I sit at idle in the mid 12afr range and it gently leans out to 14.7 as it warms up. The problem I'm experiencing is only during the initial take off and does not happen in any other gear at that rpm range. I think it has to do with something regarding the closed loop o2 feedback at idle still trying to control the fuel as I initially take off, but it can't keep up and leans out considerably. Later on I'm going to play with a bit of open loop control for the problem ranges and see if that helps at all, or maybe drop my fuel table in the problem areas down to the 9 or 10 range lol...maybe the large injectors are making life difficult.

l2r99gst

iTrader: (2)

See if you are switching from closed to open loop when you are experiencing the problem (is STFT going to 0?). If you are still in closed loop, then the fuel trims should take care of any fluctuation, unless the short term trim is maxed. If you are switching to open loop, then the short term trim won't have any effect.

Thinking about the Map VE more, I doubt that's your problem. While the VE does change from idle to when you get going, it shouldn't have that big of an effect as you are seeing, since the change in map should handle most of the fueling in the SD calculation. It has to be something else going on.

I still suggest getting a good log with both long term trims and short term trim, so that we can make a 3D chart of total trim adjustment against map and RPM.

Slo_crx1

iTrader: (9)

Ok, I'll make some quick little changes to the fuel map (still hitting some pretty rich spots at 26-28psi lol) and possibly down in the low rpm ranges as well and post up my findings.

Slo_crx1

iTrader: (9)

Ok really no change at all for the initial take off. I dropped the open loop #1 crossover point a lot for those rpm ranges and dropped the afr's into the low 11's with no real change in drive-ability. From idle at ~14.7 I hit the throttle to raise the rpm a tad, afr's drop to ~12.8-13.3 and I let out on the clutch. Afr's drop from 12.8-13.3 to around ~17-18afr until I let off slightly on the throttle, and it looks like closed loop is still controlling afr's from idle into the take off and can't respond fast enough to bring the afr's in check until around 1800rpm. I'm going to log the MAF HZ that it corresponds to and see if I can make an adjustment for it in the MAF Compensation table.

l2r99gst

iTrader: (2)

Did you verify this from logs? STFT responds pretty fast. Are you sure you aren't maxing it at that point or switching to open loop?

Slo_crx1

iTrader: (9)

Yeah, it's a slow transition for STFT that goes from -4.87 to -11.07 as my Asynch tip in is added, and then once it hits 17afr it comes back the opposite way and eventually hits +13% to richen the mixture back up to 14.7afr. This is with a LTFT Low of +2.02%, it looks like my LTFT's moved a little bit today as I added some fuel in certain areas, but still not enough to make a huge difference in my opinion. It honestly seems like my STFT is trying to compensate for the Asynch tip in and leans it out way too far for it to recover in time, which pretty much means any MAF compensation adjustment is going to be pointless as well since it seems I need to have it running in open loop pretty much for idle and up to 1500rpm. I'm also seeing about 37% throttle too during this entire ordeal.

Slo_crx1

iTrader: (9)

Ok, after dropping my open loop load area for 500-1500rpm down to around 25% throttle I noticed my closed loop feedbacks are now way all over the place. I went from a very gentle 5-6% STFT + the +/-5% LTFT Low to now seeing +15-20% SFTF and +4% LTFT Low. Very odd indeed. It actually felt like the car performed worse and leaned out even more than previously, but I think I may be on to something here. Tomorrow I'm going to reflash the VE RPM changes to clean up the trims and see what the results are. I have a feeling I may actually have to lean out quite a few portions of my fuel map now in the lower load/rpm cells. I'll keep everyone updated as I go.

Slo_crx1

iTrader: (9)

An update from the weekend, trying to clean up the VE mess with the feedback just made things worse, set the throttle crossover for open loop to kick in on anything over 20% throttle up to the 1500rpm range...and it didn't work. I can still see my STFT trying to over compensate for the fuel even when it's supposed to be in open loop, and I watched it lean out to almost 20:1afr during the last few runs. This has to be something maf related I would imagine, but I never got a chance to adjust the MAF Compensation tables to see if it made a difference.

I did notice however (not too sure how pertinent this is but worth the mention) that somewhere along the line I had lean spool enable and disable set for 1500rpm, which is right in the area of my problems. I set lean spool to come on at 2500rpm now and disable at 4000 so when I get time tonight I'll see if that makes any difference.

Any ideas though as to why I can't seem to see open loop down low in the rpm range?

charlie.tunah

iTrader: (7)

would it be worthwhile to disable to lean spool and see if that is the culprit? I wonder if that is why some folks have this problem, but others say they dont? Id guess its about 50/50 with folks that run lean spool and folks that dont. Im going v7 sd this summer and Id love to know all these issues where worked out before hand.

03whitegsr

iTrader: (8)

Is anybody using lean spool with the SD patch?

To be realistic, even on the MAF there was issues with this area. My car would go incredibly rich (10:1) below 2000 RPM under certain condtions for seemingly no reason. Makes me wonder if it is realted to this issue.

l2r99gst

iTrader: (2)

When I was running SD for a short while, I had lean spool enabled, as I do on my MAF tune. I don't remember having any issues as being mentioned here. I've been meaning to swtich over again to go full time SD, but just haven't had the time with other things going on. I haven't really touched my car in quite a while (modding/tuning that is).

Slo_crx1 - Lowering your open loop switchover will just make things worse if you are truly running lean or have a fueling/VE issue. Without closed loop to correct for it, then it will obviously be worse.

It'd be interesting to see what your lean spool changes have. Hopefully that's part or all of your problem.

If not, if you can pinpoint the area to a certain map or certain Hz, you can try adjusting just that specific cell in either the map VE table or the maf smoothing table,assuming the other fixes like the fuel map didn't work, etc.

03whitegsr

iTrader: (8)

L2r99gst, I think it would be most beneficial for you to go back to SD and put some miles on it to see if you encounter the issue before saying it's a tuning issue. If I recall correctly, didn't you only run it for a very brief period of time before switching back to MAF because of the jitter issue?

I feel this issue is something that driving style more than anything will show it and if your driving style just didn't show it, you would never even know the problem was there. In that situation, you would almost have to look for it. To compare, I never felt the jitter you reported because I don't ever find myself driving at 2500 RPM at light throttle. But once I actually looked for what yu were talking about and intentionally drove under the conditions you described, I finally noticed it.

At least for me, if I don't pay attention to AFRs when the car is warm, I don't even notice this lean issue as the car can drive right through it without a hiccup. It's mostly just noticeable when the car is cold, as the lean issue causes misfires on the cold motor but not when the car is warm. The lean issue exists regardless of temp though and I see it when I am actually looking for it. I think if you (or anybody else for that matter) go back to SD and start intentionally driving under the conditions this pops up, you’ll see what we are talking about and I think you'll find no amount of tuning will fix it with our current understanding of the system.

I've seen NUMEROUS people complain of symptoms of this issue. I've seen a couple different ways to COVER it up. But the hard fact is, the problem is there and currently we do not have a way to fix it, only hide it. To me, hiding it is not a solution, if it was, I would have just changed my main fuel map to cover it up or flood it with tip in enrichment like others have done.

charlie.tunah

iTrader: (7)

Mine seems to have always done this on the 95630006 rom (except mine is with anything below 3k) with a slight lift off, then super pig rich. Changing BOVs helped, but it was still there to a certain degree. Lean spool off and running on the MAF btw. Wasnt much of an issue until selling my aps bov and going back to a ix bov recently.

l2r99gst

iTrader: (2)

I was on SD for about a month or so, IIRC. And was on and off several times before and after for testing here and there.

I'm familiar with the issues that you have had as well...but is that the exact same thing as crx is mentioning? Weren't yours revolved around your high altitide, incorrect baro, and cold coolant temps (or something along those lines). I don't remember crx mentioning that this was only during a cold engine, which would bring in many other factors. But that's what the discussion is about...he's asking for help, and we (I) are trying to gather as much data as possible to offer suggestions.

By no means am I trying to blame anything or anyone...I'm simply offering ways to try to solve the issue. Maybe it comes across some other way in a forum post, but I am always here to try to offer help and don't claim to know the root causes of many problems. I'm merely suggesting things to do or try. You seem to always be combative in nature against me for some reason. I simply played it off as frustration in dealing with problems like this.

That's why, in the case of crx, I asked for logs serveral times. People explaining things are one things, but logs are hard data that we can examine and analyze, then make changes, and see the changes in data. If there is no solution, there is no solution...but that doesn't mean we shouldn't try to fix it with what we know. Especially if the issue crx is mentioning isn't the same exact issue that you have been battling for a while. It would be wrong to dismiss it quickly, and offer no help.

KevinD

iTrader: (56)

from experience, i can tell you it has nothing to do with o2 sensor feedback and closed loop/open loop transitions. i had a customer car a few months ago i was working on that had a hell of a problem with leaning out at 4k rpm (unrelated to this problem). anyway, after a few weeks of playing with it, i disabled the front o2 sensor entirely and ran the car open loop 24/7. car ran 100x better (reason it wasn't running well before was because it was a cheap aftermarket front o2.. avoid them at all costs). even with the car in open loop 100% of the time it still gets the lean out issue at low rpms when leaving a stop light. i'm going to be adjusting the open loop fuel tables in this rpm/load range further to see if it helps.