Newbie Tuner Needs Help With Idle Surge

[wantsum411]

Hello everyone I have a LS1 m6 '72 SS Camaro ....H & C setup that was dynotuned by Goeff Skinner .He did an excellent job ,Drivability ,Perf. etc.
I have since purchased HP tuners 2.2 to assist with my LSX Conversion shop, start ups ,gear changes,ect.Well I have very lil time to tweak on my own stuff.
I have since added to my Camaro a Fast 92/92 & replaced the mid legth headers with L/T's & have surging issue after driving ,once the car is stopped it will drop back to normal idle everytime within 3-4 seconds ,sometimes it will not surge.Most all startups are good with normal idle .So where do I go from here ,Maf & VE tune ?Thanks for any help !

[Tongboy]

VE tune
MAF tune
idle running airflow tune

is what i understand to be the steps to take then you go to the throttle cracker/follower tables to get the return to idle fixed up

[wantsum411]

So start with the VE table first..to within + or -3% variation then move on to the MAF calibration table second ?

[Rinkrat456]

VE is important, but it's only 1/3rd of the idle equation IMO. Spark and air are equally important as proper fueling.

Best way to tell for now is to post up a tune for starters and preferably get a log up of this idle surge to see what's actually happening.

[wantsum411]

I will get a log up on Saturday..this will be my first break from the jobs here at the shop.Just normal cruising ...some WOT too or al lil of both ?

[Rinkrat456]

WOT blasts should never happen while VE tuning, IMHO. I'd focus on getting separate logs for a cold start idle, another for cruising around town and if you can a third to demonstrate the idle surge.

[wantsum411]

Yes I am aware not to WOT while VE or MAF tuning ,I will gather a cold start log & my 1/4 mile idle out to pavement & some normal cruising with some variation ...the idle up issues are always when you come to a stop.THANKS for all the help.
I should have the logs up Saturday afternoon sometime.

[wantsum411]

Here are some driving logs & a couple of WOT logs.Thanks for any input !
You can see the idle surge to 1700-1800 rpm or so & sometimes it will not search at all upon stopping ?
Yes I know the AFR is a lil rich besides the idle that is why I am here .Thanks once again for any & all help !

[kjhallex]

Please tell me your wideband is reading wrong... That is more than a "lil" rich, get your fueling right first then worry about idle problems, and post your tune also.

[wantsum411]

I am looking at only the WOT AFR under 100% TPS which is 11.88-12.00 ...& needs to be 12.7-13.0 ,correct ?Anything from idle to 2600 RPM should be 14.7 correct ?A copy of my tune is attached.
Stock block LS1 M6,PRC 5.3 Stg 2.5 heads 62cc,Pat G Custom cam 231/239 Dur,617/623 lift,109ctr line,FAST 92/92,Stepped LT's 1 3/4 to 1 7/8 into 3 " x no cats.
As far as adjusting my PE ,my EQ Ratio tables range are 1.250 at 0-1600RPM,1.271 at 2000-2400 RPM ,1.114 at 2800-7200RPM.How big or small of adj. to start with .025 log another run until it is right ?
If I need to read some other place let me know ,I realize this may be simple for some as I stated I am a NEWBIE TUNER .Thanks for ALL the help ! !
I posted the original Dynotune & tune which is in the car after a few Idle adjustmants.

[Rinkrat456]

Oooofta. There's a lot going on here that you're fighting.

I'm in the mood to help. Check back in an hour when I'm done typing.

[wantsum411]

NOTE....The original Dynotune done by Goeff Skinner was with a LS6 intake,Mac Mid legth headers & a Magic Stick 3 cam 237/242...603/609 .All the logs here are with the listed changes/upgrades .
Please tell me this gets easier the more you do it....right now it is a bit overwhelming or maybe the word I am looking for is FRUSTRATING !THANKS FOR HP TUNERS Website & all who are willing to help us NEWBIES !

[Rinkrat456]

Open your most recent tune, Save As, name it something else like "working tune" so that you don't lose your recent tune. We're gonna work with "working tune".

First thing with a tune is setting your absolute parameters. These include things like engine size, injector data, Air Fuel Ratio, RPM limits, O2 voltages and torque management that you wish to keep or remove. Tire size, rear end ratio, fan settings, A/C settings. Make sure your injector data is correct! If you don't know if the data is correct, call the tuner you were working with. If they don't know, pull an injector and read the part number off them to look up your own data. Proper fuel injector data is critical. Right now your data is set up as a return setup...is that the type if fuel system you have? I usually take this time to also set my timing tables to what I think they'll look like which is just based on experience tuning with certain heads and combos.

OK...we've gotta tune your VE tables. Yes, plural, you've got a primary table and a secondary. The primary table is your main fueling table when the engine isn't in speed density mode, but if you're planning to run speed density then whatever changes you make to your primary table you copy over to your secondary. Open both your primary and secondary table for a second and compare them side by side....you'll notice the secondary table skips every other row...so when you make changes to your primary table you copy the multiples of 10 (20, 30, 40, 50, 60 ----100) from the primary table to the secondary.

Squirrel!....first things first, set up your tune to be ready for tuning.

Follow along.

Engine>Fuel>Cutoff,DFCO>Deceleration Fuel Cutoff "DFCO Enable Normal"> Enable Temp = set to max 285 to disable this. By doing this your histograms for short term fuel trims (STFT's) will be more precise (I'm gonna say this a lot soon).

Engine>Fuel>Open & Closed Loop>Open Loop> EQ Ratio = set columns 140 through 248*F to 1.00 for all MAP values in those columns. This makes sure all your fueling is commanding 14.7 when the engine is up to temp and nothing is getting in the way. Again, the idea here is to tune the VE tables with no other modifiers so you can be more precise.

Engine>Fuel>Open & Closed Loop>Open Loop> Closed Loop> Closed Loop Enable ECT vs IAT = set all to max 285*F. This forces you into open loop the whole time during tuning. You can change this back later.

Engine>Fuel>Open & Closed Loop>Open Loop> O2 Rich/Lean vs Airflow> Bank 1 and Bank 2 = set all values to 451 for now.. When you have a good feel for what these voltages do you can play with them later. For now all set to 451 which = 14.7.

Engine>Fuel>Open & Closed Loop>Open Loop> Long Term Fuel Trims LTFT Enable > LTFT = Disabled.

Engine>Fuel>Power Enrich> Power Enrichment PE Enable TPS Cold = set all RPM ranges to 100 throttle position percent. This makes it so you never enter power enrichment unless you go to 100% throttle. When tuning, try to stay 99% and lower but just in case read on.

Engine>Fuel>Power Enrich> Power Enrichment EQ Ratio vs RPM = 1.00 in all values . In case you DO hit 100% throttle, set all values so that your A:F is still 14.7 and nothing is affecting your fueling so it's....more precise.


Engine>Spark>Advance>Main Spark Advance> (I'd re-do your spark tables but for now, copy the high octane table to the low octane table. . Make sure you're tuning with the best gas you plan on using and any time you log knock and make adjustments, make the changes to your low octane table. This is because the PCM uses the low octane table when in speed density mode.

Engine Diag>Airflow> MAF Sensor> MAF fail high = 0. This disables the mas airflow sensor so you can tune the VE tables and enter speed density mode. If you don't want to see the engine light, go to the DTC's tab and uncheck the SES enable box on P0101 thru P0103.

Save "working tune", and flash these changes to your PCM.

From here on out you're set to tune your VE tables.

Open your scanner, I can usually do everything I need with the default scanner config. Connect, start logging and start the engine with your new settings. Open the VCM controls and under the fueling tab, click "reset fuel trims." You only want to do this the 1st time while you attack the VE tables or when idle tuning. Make sure you're looking at your gauges, Chart display and Histogram display. You're going to focus most on histogram 4 which should be VE short term fuel trims, and histogram 2 main spark knock retard. Go out driving for 5 minutes and bring the engine up to operating temp so the O2 sensors are switching properly. Reset the log once warmed up by clicking the stop button and start button shortly after. This is so your O2 sensors are only giving you the best data (to be.....the most precise....)

Open histogram 4 while driving around and find some secluded piece of pavement and go have some fun. Use all your gears available and try to hit as many cells in histogram 4 as you can. You can see across the top of the histogram that each column represent RPM ranges and each row represents MAP value. Obviously lugging a M6 in 6th gear at 30mph will lug your typical Camaro or Vette down below idle RPM's at really high MAP values. The opposite goes for 1st gear use - revving up really high in 1st gear and then letting off will start filling in the 6-7k RPM ranges at 15kPa MAP values. You want to use all gears at all ranges and hit as many cells as many times as you can. I repeat, hit the cells multiple times to get a good average in each cell. Sometimes when you hit a cell more than once it'll change to a more precise value.

If the histogram is extremely dark green it means you're running really rich in the green (negative) cells. Negative values means your PCM is trying to subtract fuel. Any dark red cells means they need your attention ASAP and your PCM wishes you would add (positive) fuel. Use this histogram you collected to tell you where your changes need to be made. When you've populated as many as cells as possible from 800-6000+ RPM's and all MAP values in between, select all and copy the histogram and if numbers are beyond 10 or -10 in most cells...bring the data over to your 'working tune' and open your Primary VE table. Select all inside your VE table and right click > paste special > Multiply by %. This should change your VE table and make it look like a choppy mountain range. Make sure the primary VE table is still all selected and hit the "smooth selection" button once or twice until the choppiness looks smoother. When you start getting values under -10 and 10, you can "Multiply by % half" so the VE table doesn't change as drastically. When I get within -5 and 5, I start to move these values by hand. Remember when I saw that squirrel and started talking about the primary and secondary VE tables? This is that situation...open both your Primary and Secondary VE tables and use the 20, 30, 40, -.....100 rows from the Primary over to create a new Secondary VE table. If there are extremely rocky spikes in new the Secondary VE table, select all and smooth only once.

While we've got the tune open, go back to your scanner and look at histogram #2. If there are any cells reporting knock values during your last log, go back and open your editor's low octane table and scale down those cells where knock is present by half of what is reported. (if the histogram claims you experienced 6 degrees of knock retard, subtract 3 or 4 from the low octane table in the cell that knock was found).

Save these new changes to VE and spark as your 'working tune' and flash them to the PCM.

Repeat the scanner steps of warming the engine to operating temp, resetting the log scanner when you're ready, hitting as many cells in histogram 4 (STFT's) as possible and copying the data to your primary VE table (and then copying those values to your secondary VE) each time. Keep an eye on histogram 2 for knock retard and make changes to your low octane table as needed. When you start seeing lighter green values and light pink/red values that are within +/-4 or 5 percent, start focusing more on the lean condition values. A safe tune should have STFT histogram values of -5 to 0, preferably -3 to 0 for a more precise tune. There should be no red cells above +5 when you're done, preferably 0 to +2 tops. Each time you modify both VE tables and reflash the PCM with your changes you should see smaller values if you're doing things right.

When you're satisfied with your VE table you can move onto idle tuning. Let this be your guide.

http://www.silveradoss.com/forums/to...sing-hptuners/

After your VE table is spot on and idle is solid, re-enable a few things like DFCO, LTFT Enable, use a stock LS6 as an example for Power Enrichment settings until you get a better feel for what your Power Enrichment's EQ Ratio vs RPM could look like.

More to come after you do a few of these things...I'm tired, my fingers hurt and this is enough to keep you busy for hours.

[Rinkrat456]

Here's a tune to look at for the time being. This is a '99 Corvette LS1/manual I'm working on currently. It's almost done and it lays 150 feet worth of black lines on the pavement now where just three days ago it couldn't do a burnout or throw you back into your seat. It's a stock bottom ended LS1 with LS6 intake, 39lb injectors, ported and polished 799 heads, 228/230 cam, NGK TR55 plugs and 91 octane. It idles at 800 with rock solid stability, spark tables are optimized for 89 octane but the driver usually runs 91.

[Rinkrat456]

Those logs you provided showed more tuning is needed - almost starting over. No need to analyze more than one or two of them once you start looking at how unstable things are. That's ok though, read along what I typed earlier and you'll have a good start.

I did however focus pretty heavily on the idle log you uploaded though. The link I provided about idle tuning should help you immensely.

[wantsum411]

Thanks Patrick,Injectorsare scaled ....42# Green tops ,Walbro 255 in tank pump.
Even with all my issues the car stilll runs 11.58 1/4 @ 119mph & 7.30's 1/8 .It will get out of shape in 3rd @ 55mph so she should respond well to the tuning .I am working 10-12 hr days here at my shop so it will be Sat. before I can do anything.I will keep you posted.
I have some videos on my website of how it runs in its current tune @
http://bluecollarlsx.com/videos/

[wantsum411]

Well I finally got a LIL time to log ...as for the settings you laid out my VE LTFT histograms would only populate 0's Log is attached .Also car would not hardly idle & popped & ran bad under those settings .My car is MAF tuned & not SD for what it's worth .
I returned to the settings as laid out by Bob @ The Tuning School & have attached those logs also ,I noticed this time out my LM2 A/F reading was dif than what was logging ,what could be the deal ?
With the settings as laid out by Bob at The Tunuing School I
Set MAF Fail High @ 0 Hz
Set both Hot & Cold PE Enable TPS to 100 %
Set DFCO Enable Temp to 250 F.
Cell hits were changed to 5 to remove any bad data or spikes
Fuel Trim was reset once for a fresh start
3 test were done to collect data ,all in 2nd gear .
Test A -2000 to 5000 RPM in 500 RPM increments holding each at 5 seconds
Test B - 2000 to 4000 RPM in a slow or moderate rate .
Test C - 2000 to 4000 RPM in a more rapid rate but not above 50 % Throttle .
I copied ,Pasted ,Multiplied by % Ect. as # 2 looks best to me I think I should have went to 1/2 % but this is what I had time for .The idle is a lil better & does not hang at 1500 - 1800 RPM nearly as bad & my throttle response seems alot crisper .
I Liked the drive around & have fun set up you outlined Patrick but could not get it to populate in histograms 3 VE LTFT maybe you can tell me what was wrong or what I need to change .THANKS for any & all help .
Not sure what is up with my wideband it is a LM2 ,my O2 stays in my car all the time ,so is my reading on the logs good or what ?

[Rinkrat456]

Above, you disabled LTFT's because I recommended you use STFT's to tune the VE table. Use short term fuel trims if you believe your tune is close, otherwise re-enable LTFT's and use those to get under +/- 10 and then use STFT's to dial it in even further.

[wantsum411]

So do you agree to start with #2 log results then go to STFT to tune ?
What's up with the way the car would run with the setting's you set for me or what am I missing ,it would not hardly idle & if you tried to accelerate very hard at all it would pop & sputter a lil .

[Rinkrat456]

The whole idea behind tuning the VE table is to exclude as many fuel multipliers and helpers as possible, so until the VE table is tuned and certain functions turned back on, it'll feel a little rough but progressively it should feel better as you get closer to the final tune.

I agree with you, that you can use STFT's to dial it in from here. Focus first on your lean areas, there were whole ranges of cells lean by the same value ...which for you could mean multiplying the corresponding VE table ranges by that % richer (1.05, 1.06, 1.02...ect). If your common STFT's are lean by 5-6%, I'd try multiplying that area of the VE table by 1.06 to bring them closer to 0%.

Can you post a recent tune?