My car goes really lean when you let the clutch out (or in...whatever makes the car start moving). On the original lancer rom, no problems, but using the evo tephra speed density rom, I'm seeing that one issue. It's a lot worse when cold, to the point of my wideband going all the way lean where it can't even display it, just "---". If I hold the clutch and pedal right where they are, it sputters for a bit really lean, then all the sudden the RPM climb and the car is fine until I come to a stop again. The same type of behavior is also present if I shift gears and I'm at a very low RPM in the next gear.

In EcuFlash, what could affect initial burst of fuel when coming off of idle, and be somewhat temperature dependent?

 

Oh, and it also does it when I just rev the engine sitting still. Not like a hard rev, just a gradual rpm increase....if it's cold enough the rpm's actually drop and the car sounds like it's gonna stall. Is it ISCV maybe?

 

I don't mean to bump my own thread, but I noticed one other thing this morning. When you (I) start the car, the wideband reads 14.7, then after about 10 seconds it starts to creep up leaner, and leaner to 17 or so. It drops back down to 14.7 at idle as it warms up.

The real point though, was this...for that 10 seconds, when the AFR sits at 14.7, if I start driving there, there is no leaning, no hesitation, no stuttering. As soon as the AFR starts to climb lean though, the behavior is there. It's basically like 1-2 seconds of no response from the injectors or something, and then all the sudden the car and RPM's "surge" to what you would expect. Thoughts on what ecuflash table might help tweak this out?

 

Here is a graph of what happened yesterday when I started it up as cold as it can be, just so you can see a visual of it. I basically just pushed the pedals like normal, nothing crazy, or anything, just a normal start from a stop.

Next Pic is a log view of basically turning out of the parking lot, and then getting up to 40 on the lil road next to work. So, the thing I was sort of seeing though, is on that initial shift, it goes lean like starting from a stop. I have tried adjusting a couple tables like ISCV startup, MAP VE, and maybe a bunch of work on the MAF tables that's all been reverted, since it didn't have the desired effect.

One thing that may also be important, I'm always a little lean when starting up, then I'm fine when it's warm. I can post VE and what not if anyone thinks that might help, or a pic of it....Meh, I'll do it, here is.

 

I don't mean to keep bumping myself, but I wanted to add that I have increased VE vs load or whatever it is substantially in the 50-80 range, which I see when taking off from a start, and the issue is slightly less, but still very obvious when cold. The second thing I noticed, my logs when on MAF also did the same thing.

I thought it might be the IPW startup latency, because my injectors don't match stock, but that turned out to have no effect at all.

Also, finally check this image with injector pulse width included...points to the issue perhaps, thoughts?

 

Looks like you are adding allot to your VE table. Something is not right. VE in the low load idle areas should not be in the 100's. Your injector scaling and latencies are probably wrong. Also make sure you are using the correct map sensor scaling.

What are your fuel trims like?

 

Keep in mind most people scale ve as a percent, I have mine set as 1-128, so I can see each increment. When it was percent, I would hit plus or minus, and the number wouldn't change sometimes, and it just bothered me so bas that I changed scaling to milt-128 or whatever.

I would probably bet my scaling or latency values are wrong, but I stay in open loop all the time. Still I may go back to MAF rom, work on my injector scaling, then have another go at the sd rom so I can tell if my injectors are giving me fits. For map sensor scaling I think its right, but I will have another look in the am.

I also increased tps delta accel, and it got rid of the leaning when warm, but on first start of the day, its so lean on the clutch release. Is there some sort of, like...idle table for the area between idle and going into gear or something? Roadspike said it could b that before the sensors all" wake up", its in a starts limp mode of some sort, but because the engine is so different than an egos, the predefined values aren't close enough, so it sucks in that area. I do remember itbeing even worse in winter, and that actually was on the old injectors that I know were scaled perfect...hmm, more digging I shall do, it has to be temp relatedthough I think.

 

I would look at these tables:
Post Cranking Transient Enrichment vs Coolant Temp #1
Post Cranking Transient Enrichment vs Coolant Temp #2

Maf Comp vs Coolant Temp #1
Maf Comp vs Coolant Temp #2

Get your fuel trims, scaling and latencies in check and then work on dialing on the cold start.

 

I'm thinking good advice on latencies and scaling, because I went back to MAF...and the car drives a crap ton better on the MAF except for at idle, with scaling at 420. My SD scaling was at 375, so something is quite awry. The reason I went to speed density was the EVO Maf adapter made me idle way too rich, I think because the honeycomb got ripped out by the previous owner (I hate that btw...he didn't tell me when I bought it) So, it cruises, accel's, etc all really well on the evo maf, except idle, so I will go back to the lancer MAF sensor, and then see how that works as well.

Basically, something is off in my SD tuning with various different roms. I have a working SD "2.0" rom that I'm using, which has that really weird VE table I posted above. I also tried to get an original SD rom for 9653 running on my car, but it just sucked hard. I run lean at idle, especially idle with the scaling at 420 or whatever where it works well on MAF. Thoughts? Should there be something specific I increase to make the car run richer? Also, to get the car to actually idle, I have to increase ISCV significantly.

 

So, does this stuff look weird? This was what I finally landed on today, while using the oldschool speed density stuff. I get "hot spots" I would call them, or "rich/lean spots", so it's most likely because I tweaked the wrong tables. Something is weird, because no matter what ROM I use, I'm lean at idle it seems. I used latencies and scaling that I knew are right this time, and just left them as is. Anyway, without further suspense....

Oh, and it did pretty good, ran well and was pretty close to within the specified AFR's...not perfect, but close. I was in forced open loop, so it would have been pretty unnoticeable if I had closed loop on.

 

Not sure if your problem specifically relates to SD - it could just be a Tephra modded ROM thing in general. Lots of people (including me) have the same issue where the car runs lean briefly when getting back on the throttle during the cold start cycle (e.g changing from 1st-2nd-3rd etc). There's a few threads on here which discuss it, but I haven't found a solution as yet.

My issue started when I went from 90550001 v5.1 to 96530706 v7. If I go back to 90550001 v5.1 it goes away again. Now that 9055 v7 is out, I might try that to see if it works.

Here's a thread where I posted some of the fixes that I tried:
https://www.evolutionm.net/forums/8868374-post440.html

 

I would leave the MAF Comp alone until you get the RPM VE close. That RPM VE table is not right. You should not be at 105 at 500 rpm. I think you need to take a step back. Get it dialed in on an EVO maf and your injectors, and get your scaling and latencies down. Then id try and move over to SD. You are changing multiple things and are more than likely contributing to your problem then solving it.

 

Yeah, I did go back to MAF today, and on the EVO MAF it's perfect everywhere except at 18 & 25 hz, which I believe is because of the honeycomb getting ripped out. The Lancer MAF is very good as well, but it's so small that I wanted to get rid of it because it could be robbing me of power. Still, in either case, the scaling and latency was near perfect...so I kept that same scaling and latency when moving up to SD.

Would you increase the MAP VE table instead of increasing RPM VE in that area?

My biggest issue with SD, any ROM, seems to be at low load, above 3000 rpm the car runs really rich. I don't spend a lot of time there, but it makes for some awkward looking maps. Do you think my car being SOHC, and longer stroke than the evo has anything to do with the VE being seemingly different? Also, compression is higher, if that makes a difference, which I don't think it really does.

Thanks again for giving me helpful advice and direction btw.

 

Alright...I went back again, and really rocked that thing! I did somewhat the opposite of the guide on tuning SD, but I got the MAP VE right first, then I went back and tuned up RPM VE, and it ended up like this...I'm really happy with it, still a little lean WOT, but I can iron that out tomorrow.

I think I was just all *** backwards on tuning it, and going to SD (the original one) really helped me get it sorted out. I bet I could go back and straighten out the one with the 3D ve table...maybe, might stick with this one for a bit though. Oh, and latency and scaling of injectors is still "right" as far as compared to MAF.

Thank you again for making sure I didn't stay with those bunk VE RPM values....I'm going to keep working on it, but the tune feels really good, and doesn't go lean upon startup either!

 

Looks better. Go drive it for like 30min and let it idle for a while and see what your fuel trims are doing.