Idle hunting?

[Speedforhire]

Would someone please chime in and see what adjustments I need to make to this tune? The car runs great and idles nicely, but it has a very slight idle hang when parked. The running idle rpm is actually 100rpm's more than the desired rpm. It will eventually fall to the desired level but it takes some time. The car will also hunt when the throttle is released abruptly. It dips to about 600rpm's then recovers back to the high value after a few seconds (that seem like minutes).

I really can't nail it down. Please help!

2013Z16GSVetteA6.hpt
Post#2.hpl

[Niemer]

Your idle airflow is pretty high in the low RPM regions, try lowering it 3-4 g/s.

[schpenxel]

Would someone please chime in and see what adjustments I need to make to this tune? The car runs great and idles nicely, but it has a very slight idle hang when parked. The running idle rpm is actually 100rpm's more than the desired rpm. It will eventually fall to the desired level but it takes some time. The car will also hunt when the throttle is released abruptly. It dips to about 600rpm's then recovers back to the high value after a few seconds (that seem like minutes).

I really can't nail it down. Please help!

2013Z16GSVetteA6.hpt
Post#2.hpl

I noticed your min idle airflow table starts at 11.something, decreases to 9.something (as RPM increases), then starts going up again. All stock tables I've seen only increase as RPM increases.. I think that is your problem. It doesn't make sense for min air to go down as RPM goes up. I would expect erratic behavior from it being setup like that.

I would go back to the stock table and try to keep trends close to stock. When you make changes at first, change the entire table by a percent or whatever. I had a problem where my min airflow was too low and after engine braking it would almost stall/hunt for the right RPM for a while. The best results ended up being by multiplying the whole table by 1.25 or so then I brought some of the higher RPM cells down a little bit at the end. I'm assuming I needed to add this much due to having added a blower which the engine now has to spin at idle.. Lowering some of the higher RPM cells seemed to help in bringing RPM's down faster during shifts.

What are some details on your setup?

I can send you a copy of my min airflow table if your setup is comparable at all.

[Speedforhire]

2013 GS LS3 A6 car:

227/243 .614/.624 113+2 LSA
1-3/4 headers w/ catless exhaust (no muffs)
160* thermo
AIRAID intake
stock stall A6

I tried reducing the table and it didn't help at all. It did calm the car down a little. Does that make sense? LOL!

[SultanHassanMasTuning]

your idle hunts due to adaptive idle getting overworked.

your airflow table

flatten your 1000rpm and below and increase say 5% at 200rpm and interpolate to your target.

you have 20 degrees in your idle timing tables, you should be close to that now your hoovering around the 10-12 advance

you need to decrease idle airflow as mentioned.

[Speedforhire]

New air table.........but it still falls too fast and then rebounds. ??????

Idle log with revs for an example.

[GHuggins]

Idle proportional airflow= keep increasing (*1.2 good starting point) / Idle integral airflow = keep decreasing (*.8 to .55 good starting point) = You'll eventually have an idle hang meaning you went too far. Before this set min air table to where you can put it into drive without idle dips and go from there. Just don't increase it too much. Go back to stock and add 2.5 to 3 to the entire board, should be enough.

Also noticed you have headers with no cats... Did you get your O2's dialed in correctly? If you hold it at 1500 rpms, does your engine tone and rpms change with O2's and fuel trims switching? If so get them in better too. Looking for a constant rpm and engine tone while maintaining rpms and decently slow switching stft's. Can't give you any direction on this because it seems all are different. Typically increase O2 proportional 1.2, have even seen it respond well to decreasing or *.835 then increase O2 integrator delay somewhere around 1.15 to 1.5... This will help tremendously with cruise surge or idle hunting/surging.

Then due to the fact I don't have my labtop to look at your tune, with your cam you should have also retarded your injection timing somewhere around 20+ degrees... This will also help with cruise surging or bucking...

Lots of things to change that the OE spends countless weeks to months dialing in, so don't plan on it being a first time correction. You may have to keep fine tuning the tables, until things are working together correctly.

You can also play with timing and a few other things, but think this is enough for now.

Hope this helps

[SultanHassanMasTuning]

fix your fuel trims

[Speedforhire]

fix your fuel trims

I don't know how! :-(

I'm more of a gearhead, not an engineer. I could disassemble this whole car and put it back together but tuning is a ZEN art form. LOL! I can turn the LTFT off and the STFT will stay negative, but I can't keep them from dipping all the time.

[SultanHassanMasTuning]

from a quick glance looks like you need to remove from your maf transer

from 0Hz to say 5500Hz 5% so highlight and multiply by .95

also try having your timing in both and Idle and park timing maps or 18 degrees

[Speedforhire]

...................Idle Base Spark vs. RPM vs. CylAir updated.

[Speedforhire]

Would someone please view my current tune and make recommendations?

I owe you guys a beer.

[GHuggins]

What exactly has been tried and what effects did it have (good and negative)

Do you know how to make your own histograms? This will help immensly with getting your fueling correct.

[Speedforhire]

Histo's don't want to run. :-(

Main spark and Retard are the only two that show info.

Histo_Message.jpg

[GHuggins]

Those histograms only work on the older gens. You have to make your own for the newer.

Start by making sure you still have all of the "self populated" pids in the table. These are the ones that are originally in the main table view when you open it up. (short term & long term fuel trims, O2 voltages, rpm, ignition advance and so on)

Now click on one of your empty tabs then right click on it... Go to configure user defined... Click on one of the empty "undefined" parameters on the left then on the right where "name" is enter in Fuel Trim Correction... Now go down to the empty function area "white line at bottom" and enter in this --- ((([PID.6]+[PID.8])/2)+([PID.7]+[PID.9])/2))) --- Only enter the part with colons --- Now hit the (X) and accept changes. Go back to which ever empty blank line in the table you want to enter this into - right click - insert - Now under user defined you should have a Fuel Trim Correction option. Double click on this and it's now in your table display.

You also want MAF lb min, MAF HZ (SAE), RPM, MAP kpa (SAE), Dynamic Airflow, Intake Valve Temp, Inj Pulse Width, TP (SAE), ST&LT fuel trims and engine run time all in your table. These you can get straight from the engine section...

For the engine run time, you'll also want to make another user defined on top of this one - call it run time - then take [PID.2131]/60 to help with confusion. Regular engine run time has to stay in the table for this one to work unfortunately, so if you don't want it don't bother. I use it as a timer for the "rich after flash issue".

Now go to your histograms. You can pick a unused tab or replace one already in existance. Now Click on the little folder looking icon beside the "plus" symbol. Click on the histogram tab you want to make the new histogram in on the left column. Where name is - enter MAF Error Fuel Trim Correction - Where PID is - Click on this and then go to user defined and click on your fuel trim correction pid - Now click on Row & Col Axis - Click on Sensor in the middle "Col (TOP) Axis Header" section - Insert Mass Air Flow Freq - On units - Find and click on "Hz" - Now enter in just as it's typed -

0,150,300,450,600,750,900,1050,1200,1350,1500,1650 ,1800,1950,2100,2250,2400,2550,2700,2850,3000,3150 ,3300,3450,3600,3750,3900,4050,4200,4350,4500,4650 ,4800,4950,5100,5250,5400,5550,5700,5850,6000,6150 ,6300,6450,6600,6750,6900,7050,7200,7350,7500,7650 ,7800,7950,8100,8250,8400,8550,8700,8850,9000,9150 ,9300,9450,9600,9750,9900,10050,10200,10350,10500, 10650,10800,10950,11100,11250,11400,11550,11700,11 850,12000,12150,12300,12450,12600,12750,12900,1305 0,13350,13500,13650,13800,13950,14100,14250,14400, 14550,14700,14850,15000

Now if you notice this is the Hz airflow scale straight out of your tune. You now have a histogram for making fuel corrections to your MAF transfer curve. Just make sure to smooth out any humps that may apear after each of the first couple of remaps.

You can setup histograms the same way for pretty much anything now. Just make sure what ever your trying to log is in the main table display, otherwise it won't work...

[GHuggins]

Then of course if you have a wideband you can make a second histogram with all the same settings and where you entered in the fuel trim correction sensor, just enter in your user defined wideband setup.

You can use this. Just enter this into your table as air fuel error

(([AUX.20121]/[PID.6001])-1)*100

Ohh, almost forgot, your going to need to add Cammanded Air Fuel Ratio to your main table display from your vehicle pid list.

[Speedforhire]

...........same message: This histogram doesn't support the currently loaded parameters..............

Hist-FTC.png

I get data in the Table Display...........but not the Histogram

..............I'm ready to drive it off a cliff! :-(

[schpenxel]

...........same message: This histogram doesn't support the currently loaded parameters..............

..............I'm ready to drive it off a cliff! :-(

Post a picture of the table display.. the whole thing

That is where your problem is

[GHuggins]

Yes, if you entered in the histogram setup that I listed and have the table pids as listed, then it should have worked...

What version of 2.24 are you using? Are you using beta? If you are try with the latest version of 2.24.

[schpenxel]

...........same message: This histogram doesn't support the currently loaded parameters..............

Hist-FTC.png

I get data in the Table Display...........but not the Histogram

..............I'm ready to drive it off a cliff! :-(

you need to be logging MAF hz

Without it any histogram that uses MAF hz in any way will not work.. i.e. what you're seeing happen now