LNF Misfires and Rough Idle on Cold Starts

[splash]

Hi there, I was wondering if someone would be able to take a look at my tune and log and let me know what they think. I see based on this forum that this is a common problem but there has not been any clear-cut answer to the solution to solving these problems. I'll get random misfires and random surges and the rpms will fluctuate quite a bit.

I have tried everything as follows trying to solve this problem:
New coils
New plugs
New upstream O2
New Evap purge solenoid
Cleaned MAF and Map Sensors
Lubricated bypass valve
Valves were blasted 10k miles ago
New boost control solenoid

No change still having idle problems. 100% of the time other than cold start idles, it will idle fine and under all other driving conditions the tune is spot on. Only mods to the car are Catless Downpipe and K&N intake. Before I installed the intake, I used to be able to run no cat warmup and it would idle pretty good. I feel like the intake is most of the problem for the rough idle. I just can't figure it out. I have tried changed tons of different things in the tune to no avail. If anyone would be able to look at it and give me feedback I would be thrilled. I will post a log and my tune.
new plugs new coils cold start.hplDexterSRI91-14-2.hpt

[cobaltssoverbooster]

try setting cold and warm cam tables for idle as follows....intake value = 10 every cell, exhaust value = -6 every cell
go to your ignition tables and in the top left table highlight from 400-1000 rpm and out to 30% load and set the highlighted section = 20
now copy entire table and transfer to the remaining 3.

that should stabilize your idle airflow and help you tune the fueling in that range to prevent stumbling. When adjusting ignition advance for idle make sure you log the map sensor as well. the boost sensor only tells boost and your goal will be to do 2 things...i make the vacuum as high as possible and 2 produce a smooth rpm log. if you raise ignition and the map increases but the rpm starts to fluctuate a little, then back it off in favor of idle rpm quality.
Note: adjust the highlighted range for idle ignition all at the same time. this makes an idle plateau and helps with stability as to much or too little ignition on either side can make for some nasty idle swings.

most people shove this setup process under tuning 101 because some of the off the shelf books include this kind of defaulting information.

[splash]

So is this what you're suggesting?

[MikeM173]

There is an entire thread that discusses idle. I know because I wrote it. Why don't you try out what you have and try out other things until you figure it out???

https://www.hptuners.com/forum/showt...55951-LNF-Idle

[splash]

That seems like a good thread man. Do you have those images from the one main pic? I can guess the values pretty good I think, but I'd just like to be sure. The whole table would be beneficial.

[MikeM173]

Trial and error is best. I posted plenty of info in that write up.

[splash]

Would you mind emailing me??

[MikeM173]

Not sure there is much more to say outside of what is in the post I linked.

[splash]

The only thing in that thread that I haven't tried is adjusting the wastegate duty cycle. Other than that I have tried just about everything as far as the tune goes.

[T-Man]

I'd check for boost leaks and see if you don't have a problem with the end tanks (Assuming you have a factory IC)

[splash]

No boost leaks. Have checked many times. I just don't get it, if there was a problem, wouldn't it be apparent all the time and not just with cold starts??

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So I did a few things to the tune. Lowered idle rpm. Changed wastegate D.C to the table Mike used in his base file thread. Made the idle cam tables all the parked position. And it worked for three or so cold starts. Everything was pretty good for the most part, timing was steady, no misfires. Then today; I went to start it. 80 degree coolant temp, 70 degree ambient. It stumbled and idled really rough. It threw code P0106 (Map Sensor). I just cleaned Map sensors about a week ago. Any suggestions?

[splash]

I have tried everything to get it to idle good with cat warmup off, and have come up with absolutely nothing. It still hunts idle really bad and is then fine when cat warmup is done. However, with cat warmup on, the car idles pretty good. No misfires and a pretty solid idle. Another caveat, last week I was going to switch to E47. I had my tuner send me a tune for it. Uploaded it to the car. Mixed the fuel. 100% sure that I mixed the fuel right. The car WOULD NOT RUN. Tuner adjusted a couple of things and there was no change. Would not run. I'm back on 91 now but going to E47 for that little bit is leading me to believe that I have a mechanical issue somewhere. My tuner said he has tuned 50+ cars on E47 and has never had a problem like this. I feel at this point the only other things left to check would be the HPFP or the Injectors themselves. Any help would be appreciated.

[ECaulk]

when you changed your cam tables did you change all the idle tables including the cat warmup ones? iirc even if cat warmup is turned off it will still use the values in those tables during the initial warmup.

Also how did you adjust your DAL in the lower load area?

[splash]

Here is the tune I'm running right now on 91 if you wanna take a look at it.

[cobaltssoverbooster]

your idle should land between 20-30% and stay between 600-1000 rpm cells. try making that idle zone constant ignition. See the lnf is hard coded with idle surge ignition corrections. if you leave values that jump around in this zone then it surges harder as it fluctuates.
monitor etc, advance, map, and of course rpm at idle. if the fuel trims are dialed in then the etc should land lower between 2-3%. if it does not then you need to up ignition or adjust change the dals to close it back down again. if you adjust ignition you need to compare 2 items on the list at the same time per correction. look at map and rpm. Your looking for the highest map value that nets the smoothest idle. it is possible to overshoot timing at idle and get a higher map but end up with a shittier idle.

Keep the optimum spark in mind as well. This table can effect the sensitivity of corrections at idle. get it close using the other methods and then come see how the sensitivity is effected in the optimum spark.
your cam settings are set to maximum separation at idle which is great. particularly with big cams this helps lower the amount of air bleeding through the cylinder.

just as a hint from my experience...not every cam change needs idle rpm bumped but if i notice the vacuum is hovering in the 7-8 in range then i bump it up 50 rpm at a time to how it responds in smoothness and to see if i can get closer to 10 in. not usually a big issue in the ecotecs since the lnf has lift/duration restrictions related to miss fires but i always keep it in mind as a last resort.

[MikeM173]

OptimumTorque in the idle range will effect it. Wastegate at idleaffects it. Fuel pressure affects it. You literally have to dial everything in perfectly for idle. Well kind of. You can get away with not changing some tables, but lots of tables not mentioned can alter idle. Hence why I posted a link to my write-up. Idle is also affected by your area. What works with one car as well, won't necessarily work with another car. Idle is one of the most frustrating things, but you just have to keep playing with it until you figure it out.

[splash]

It really leads me to believe that I have a mechanical problem because when I went to E47, the car would even run. It was the same E47 concept that my tuner used on numerous different cars and said he never had that problem before. But I honestly don't know how to find a mechanical problem like that if there are no CELs. Sometimes I can get it to idle okay during cat warmup, other times it will surge multiple times. It's extremely inconsistent. I'm going to test for boost leaks again tonight.

[ECaulk]

I've been messing with my idle more lately, and like MikeM says you literally have to mess with all the tables. I've adjusted all the tables in his thread about idle and mine look nothing like his, but i'm getting closer. I'll take one table adjust it till it stops affecting idle, then start adjusting another. It's not a quick set on table to this and everything is awesome. And it certainly isn't copy someone elses tables and everything is awesome

[splash]

Well I honestly just have no idea how the car would simply not run on E47. I am absolutely bewildered about it.