Need Idle tune help

[RLSEBRING]

I have worked on my tune for some time and with various help have the car running very well except at idle.

Car is 08 A6 LS3 Hot Cam specs are .525 lift and Duration @.050 intake is 219 and exhaust is 228 Gear is 2.56

The car lurches and lunges in a time able cycle when sitting still. Depending on the setting it does this both in Park and drive as well as neutral. And by time able I mean it can idle for about 10 seconds pretty smooth than start the lurching and lunging for about 20 to 30 seconds and return to a smooth (relatively speaking idle) then return to lunging again.

As soon as I step on the gas to go it runs like it should. Before I get too far It has been suggested that I may need to install a stall speed converter. This seems excessive at this point. I'm told that the converter may be too tight but I believe it should be able to be tuned out but will but will give in if necessary.

GMPP tells me it should idle just as good as a normal LS3. I have adjusted the Idle Air, Airflow and idle timing tables in small increments from the base LS3 tune all the way to almost LS7 numbers. I cannot seem to find a happy medium. It seems to go from a very rough idle in park to very rough idle in gear. The idle just seems like it run hard instead of a nice smooth feeling.

Most everyone tells me this is a fairly big cam and needs lot s of idle air. The stock idle air:

200 400 650 800 1000 1200 1600 2000 2500 3000 3500 4000 4500 5000 6000 7000 8000
1st Gear 1.0582 0.8598 0.8598 0.9259 1.0184 1.0913 1.1427 1.2564 1.4628 1.7010 1.9836 2.2893 2.5729 2.7440 2.9101 2.9101 2.9101
2nd Gear 1.0582 0.8598 0.8598 0.9259 0.9259 0.9510 1.1303 1.1665 1.3344 1.5550 1.8090 2.0942 2.3688 2.5135 2.6455 2.6455 2.6455
3rd Gear 1.0582 0.9590 0.9590 0.9590 0.9590 0.9590 1.1070 1.1225 1.2998 1.5220 1.7480 1.9472 2.1668 2.2583 2.3810 2.3810 2.3810
4th Gear 1.0582 0.9259 0.9259 0.9259 0.9259 0.9396 1.0939 1.1094 1.2690 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
5th Gear 1.0582 0.8598 0.8598 0.8598 0.8598 0.9350 1.0797 1.0900 1.2667 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
6th Gear 1.0582 0.8598 0.8598 0.8598 0.8598 0.9350 1.0797 1.0900 1.2667 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
Neutral 0.7937 0.6614 0.7937 0.7937 0.8267 0.9259 1.0582 1.1905 1.3228 1.4551 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873
Reverse 1.0582 0.8598 0.8598 0.9259 0.9259 0.9510 1.1303 1.1665 1.3344 1.5550 1.8090 2.0942 2.3688 2.5135 2.6455 2.6455 2.6455
Park 0.7937 0.6614 0.7937 0.7937 0.8267 0.9259 1.0582 1.1905 1.3228 1.4551 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873

I am currently at:

200 400 650 800 1000 1200 1600 2000 2500 3000 3500 4000 4500 5000 6000 7000 8000
1st Gear 1.6762 1.3620 1.3620 1.6134 1.7744 1.5847 1.5512 1.6201 1.4941 1.7010 1.9836 2.2893 2.5729 2.7440 2.9101 2.9101 2.9101
2nd Gear 1.6762 1.3620 1.3620 1.6134 1.6134 1.3809 1.4147 1.5005 1.3750 1.5550 1.8090 2.0942 2.3688 2.5135 2.6455 2.6455 2.6455
3rd Gear 1.6762 1.5191 1.5191 1.6710 1.6710 1.3923 1.3977 1.4664 1.3419 1.5220 1.7480 1.9472 2.1668 2.2583 2.3810 2.3810 2.3810
4th Gear 1.6762 1.4667 1.4667 1.6134 1.6134 1.3641 1.3732 1.4401 1.3150 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
5th Gear 1.6762 1.3620 1.3620 1.4982 1.4982 1.3577 1.3610 1.4277 1.3091 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
6th Gear 1.6762 1.3620 1.3620 1.4982 1.4982 1.3577 1.3610 1.4277 1.3091 1.4889 1.7150 1.8881 1.9968 2.0609 2.1164 2.1164 2.1164
Neutral 1.3827 1.1525 1.3827 1.5209 1.5300 1.5235 1.5199 1.6160 1.4261 1.4551 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873
Reverse 1.4439 1.4850 1.5269 1.7423 1.7106 1.5930 1.5708 1.6478 1.5509 1.6240 1.8170 2.0919 2.3360 2.5109 2.6130 2.6455 2.6455
Park 1.3827 1.1525 1.3827 1.5212 1.5212 1.4788 1.5199 1.6160 1.4261 1.4551 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873 1.5873

I have ran the idle timing portion from 600 to 2000 rpm’s from 13 degrees to 35 degrees with no noticeable differences. Here is where it stands now:

Labels 0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400
0.08 35.5 35.0 35.0 35.0 35.0 37.0 40.0 41.0 42.5 45.5 45.5 45.5 45.5 45.5 45.0 45.0 45.0 45.0
0.12 35.5 35.5 35.5 35.5 35.5 37.5 41.0 42.0 44.0 45.0 45.0 45.5 45.5 45.5 45.0 45.0 45.0 45.0
0.16 35.5 35.5 35.5 35.5 35.0 37.5 41.0 42.0 44.5 45.0 45.0 45.5 45.5 45.5 45.5 45.0 45.0 45.0
0.20 35.5 35.5 35.5 35.0 35.0 37.0 40.5 41.5 42.5 44.5 45.0 45.5 45.5 43.5 43.0 43.0 43.5 43.0
0.24 30.5 30.5 30.5 30.5 31.5 33.0 35.0 38.0 40.0 42.0 44.5 45.0 45.0 43.0 43.0 43.0 43.5 42.5
0.28 25.0 25.0 25.0 26.0 27.5 30.0 32.5 35.0 37.5 39.0 41.0 42.0 42.0 41.0 41.5 41.5 41.5 41.0
0.32 21.5 21.5 21.5 22.5 24.5 27.0 30.5 33.0 35.0 37.0 38.5 39.0 39.5 38.5 39.0 39.0 39.0 39.0

I was in the process of changing the injector flow rates as I believe they are set to LS3 and not LS7 sizes but my MVPI cramped out so I am waiting on a replacement. Any input would be greatly appreciated.

I will attach my tune if anyone wants to look into it and make any suggestions. My goal at this point is to smooth out the idle. I don’t expect it to be perfectly smooth but am looking for something far better than it currently is.

[ktoonsez]

I found severla things you should try.
1. Your idle RPM is set too low in most of the fields. Set the first 6 columns to 1000 and the rest to 900
2. Set Idle Speed Minimum table to all 900's.
3. You put the 35's in the High octane table in the right spot but did not match up Idle Spark Advance Base table. It is set to 23. Also expand out the areas you want 35 in by 2 columns and rows and I would smooth the numbers around the 35's. This can cause choppy idle if not smoothed.
4. Your Minimum idle airflow table looks a little low for that cam which has some overlap. Add 2 or 3 to the entire table. If you think the table is completely jacked up, just get the stock table back and add 6 to that one and see where you are.
5. Get your stock table back in the Idle Startup Airflow table and add 7-8 to entire table.
6. On the "Adaptive Idle" fields, change the enables to 25 and 6 instead of 50 and 12. You can also reduce sensitivity of those adaptive tables by cutting them by half, just be careful, one side of one of the tables is negative.

Try all that first

[ktoonsez]

Looked at some of your logs too from Chris. When testing idle, you really should leave the hood up to try and keep a steady IAT, it is way up there during some of these logs, you should start with a more constant temp.

[ktoonsez]

Did you add headers to this car? Noticed you have Fuel trims enabled, this will reak havok with the idle in a car with headers. What is the LSA on the cam?

[RLSEBRING]

Did you add headers to this car? Noticed you have Fuel trims enabled, this will reak havok with the idle in a car with headers. What is the LSA on the cam?

No mods on the car everything is stock. Cam is 112 LSA. There's so much that I do not have a clue on yet. I am glad that you and chris know each other as you both were hitting about the same area. Some of the other PM's I was taking lightly.

I am waiting on my interface to come back from HP, should be the end of the week. I will start a new tune file with the mods that you and Chris suggested to have ready. My main question at this point is is there any alternative to having such a high idle I would really like to something low. I had the idle, with a slightly different tune, at 850 but it took a lot of brake to hold the car still and with that tune I still had the lopping, lunging.

I appreciate the both of you taking the time to look this over. Please don't take my questions as arguing with you. I really want to learn more about tuning and I am not questioning your knowledge.

[ayousef]

No mods on the car everything is stock. Cam is 112 LSA. There's so much that I do not have a clue on yet. I am glad that you and chris know each other as you both were hitting about the same area. Some of the other PM's I was taking lightly.

I am waiting on my interface to come back from HP, should be the end of the week. I will start a new tune file with the mods that you and Chris suggested to have ready. My main question at this point is is there any alternative to having such a high idle I would really like to something low. I had the idle, with a slightly different tune, at 850 but it took a lot of brake to hold the car still and with that tune I still had the lopping, lunging.

I appreciate the both of you taking the time to look this over. Please don't take my questions as arguing with you. I really want to learn more about tuning and I am not questioning your knowledge.

Send me you're stock ls3 file, I got the idle really good on two of my friends cammed cars, but they were M6's though, I might be able to help you.

[ktoonsez]

No problem at all. Just from my experience, the large LSA is not gonna idle very well at lower RPM's and will cause surging and lunging at low RPM's. You can see my mods below each post, my LSA is 114 and I have to do 850 to make it smooth as stock and you have a 112 so I don't see you getting below 850-900 and still being smooth.

[RLSEBRING]

Send me you're stock ls3 file, I got the idle really good on two of my friends cammed cars, but they were M6's though, I might be able to help you.

I am running the Mike Norris tune now pretty sucessfully except for the idle portion. The other trune is the stock tune from the car at thebeginning.

[RLSEBRING]

Sorry I don't understand the units in 4) and 5). In 4) I add 2 or 3 what? My table is in pounds per minute. Are these grams?

I found severla things you should try.
1. Your idle RPM is set too low in most of the fields. Set the first 6 columns to 1000 and the rest to 900
2. Set Idle Speed Minimum table to all 900's.
3. You put the 35's in the High octane table in the right spot but did not match up Idle Spark Advance Base table. It is set to 23. Also expand out the areas you want 35 in by 2 columns and rows and I would smooth the numbers around the 35's. This can cause choppy idle if not smoothed.
4. Your Minimum idle airflow table looks a little low for that cam which has some overlap. Add 2 or 3 to the entire table. If you think the table is completely jacked up, just get the stock table back and add 6 to that one and see where you are.
5. Get your stock table back in the Idle Startup Airflow table and add 7-8 to entire table.
6. On the "Adaptive Idle" fields, change the enables to 25 and 6 instead of 50 and 12. You can also reduce sensitivity of those adaptive tables by cutting them by half, just be careful, one side of one of the tables is negative.

Try all that first

[ktoonsez]

Sorry I don't understand the units in 4) and 5). In 4) I add 2 or 3 what? My table is in pounds per minute. Are these grams?

Sorry about that, the older version always defaulted those table to Metric (grams/second), so switch the table by right clicking in the table and go to "units" and switch to g/sec and do the adding. Sorry about that.

[RLSEBRING]

Sorry about that, the older version always defaulted those table to Metric (grams/second), so switch the table by right clicking in the table and go to "units" and switch to g/sec and do the adding. Sorry about that.

No problem, It's the little things that keep me screwed up. Everything I would read would say grams so I would have to convert to the lbs equivelent and I think something would get lost in the translation. I reset HP to metric but now will have to remember to change the tables to F instead of C for temp.

[ktoonsez]

I would leave it at Imperial for the main option, I do, and just change those table we are dealing with to g/sec. It does remember the settings for each table I believe.