2010 Camaro SS Auto Idle Issue

[Mike Norris]

Hey All,

I have tuned quite a few 2010 SS's with LS3 conversions (VVT and AFM delete) using my cam (224/236 114) and an FTI 3000 converter and all seem to work quite well.

This car came in after being done at another shop and has a larger cam, 235/242 114, and a PI 3000 converter as well as a stock TB. Everything is great as far as the trans and driveability. The issue is slow speed rolling idle.

When it first starts it will surge slightly and take a steady idle. Initial entry into drive or reverse gives some surge but settles pretty quickly. The load does change as the kpa will go from low 60's to about 70 or so. So it seems this converter is a "tight idle" 3000 stall. The fuel seems to be within 2-3% so

Now as far as I know there is not different idle airflow tables from park/neutral to drive reverse. Please correct me if I am wrong here.

So here is the tune that seems to be the best so far as well as a log. You can see that just off idle and at 2-4 MPH or so it just continually surges the idle up and down. It seems to be a lot better with the AC off, but still there and rock solid either with the AC on or off once coming to a stop.

My first thought is that since I am so perfect (haha - not) and tuned a bunch of these, that it must be the different loads it sees from park to drive. Thinking that I figure a looser converter would be better. But I have made my smaller cam work decent at a 650-700 idle and a stock converter.

I looked into a idle setup sequence by Bill Winters, but it is E40 LS2 based and on an M6. If there is a E38 specific idle prodedure out there, I missed it and would like to know where to find it. This is the first E38 I have had an idle issue with.

Thanks!!

Mike Norris

[Shrek]

Take a look at the thread linked below ...

http://www.hptuners.com/forum/showthread.php?t=39395

Probable airflow issue.

[Mike Norris]

I agree an airflow issue, and I have added and subtracted as much as 25% in 5% increments in the base airflow table and this current setting seems to be the best.

Hopefully someone can chime inwith a auto equipped vehicle that shows a load diiferential from in park to in gear.

Thanks!!

Mike

[DSteck]

Use less idle spark. There's zero room for the PCM to adjust the idle with spark because the timing is so high. These things don't need a crap ton of timing to idle. Drop that to 16-17* to start with.

[Shrek]

Use less idle spark. There's zero room for the PCM to adjust the idle with spark because the timing is so high. These things don't need a crap ton of timing to idle. Drop that to 16-17* to start with.

Agreed ... the thread I linked in post#2 suggested 14 +/- 2 degrees of timing.

Took a quick look at your tune. The Airflow Final Minimum table regarding Idle Airflow has the same values in each cell throughout what would be your target idle range. I would suggest systematically increasing the airflow values in the 1st Gear cells, in the 400 / 600 / 800 RPM range. You may find that another 10% to 20% airflow in these specific cells helps out.

Also, the Proportional Airflow and Integral Airflow tables are stock. Working with these tables helps reduce "hunting" or oscillating idle speeds when an aftermarket cam is being used.

[Mike Norris]

Thanks for the inputs guys and will try it out. Like I had mentioned what you see is what I normally do and have zero issues, but they all have a smaller cam and little load change when going into gear.

Will report back and thanks again.

Mike Norris

[Mike Norris]

It is getting better and here is the latest tune and scan. At the end of the scan you can still see it does some slight surging once you go from idle to rolling idle and hit about 2-3 MPH.

You can see the timing climbs from about 16 degrees to 35 degrees quickly. I am thinking this timing gain is inducing some of my idle issues. I can not see anywhere in the tune where it shows 35 degrees of timing at 1000 RPM (or so) and that flow rate.

Thanks again.

Mike Norris

[Shrek]

Nice to hear you are making progress. Take a look at Spark>Advance>Idle Adaptive Spark Control. This has an Overspeed (i.e. idle RPM too High) and Underspeed (i.e. idle RPM too Low) sub-fields.

Your Underspeed parameters are setup to add as much as 19.5 degrees of timing, if the idle is too Low. Guessing this is where your additional timing is coming from.

Getting a cammed car to idle properly and consistently is a bit of a mix of art and science. Often working with these tables to allow for a natural "lope" to occur will yield more consistent idle behaviour, than trying to nail down a specific idle RPM.

[Mike Norris]

I will try to zero out or lessen the over and under speed timing and see if that is it.

Thanks.

[DSteck]

Zeroing it out will kill idle control completely. Don't do that.

[Mike Norris]

Zeroing it out will kill idle control completely. Don't do that.

I know that and have dome that before with another car. I was going to try it and see if that is what is making the timing go to 35 degrees as you hit 2-3 MPH. I have had cars as low as just 5 degrees control work decent.

Will know shortly.

[DSteck]

It doesn't take a lot of spark to control it, because ideally you're staying in the +/- 50rpm area anyway.

I haven't looked at anything else in your file, but make sure you don't have excessive coastdown spark.

[Mike Norris]

Well, the idle spark timing control did change the timing the ramping up, so it is what is contributing to the issue. It was better but still doing it. I then went and looked at the idle spark control tables closely and noticed something odd. I then went to another base stock 10SS A6 tune and saw a difference. Cut and paste the other stock numbers and it is fine. Went back to my "normal" tune and with the "proper" underspeed and overspeed tables it is fine.

I do not know if it is a glitch in the factory program, or if there was an issue when the ECM was put back to stock from the original tuner. It did have an issue with the trans portion of the program loading back in the car and HPT had to "fix" it for me.

So let me know if y'all can see what I am talking about and if not, I will let you in on it.

Thanks again.

Mike Norris

[Nodnarb]

Overspeed Coast being positive?

[DSteck]

I'd still never run that much idle timing.

[Darin Morgan]

I'd still never run that much idle timing.

Do you personally feel that with cams such as a 232/245 113lsa that 21° is to much even if the MAF is close to the TB? With certain CAI I find that 21° is the only way to calm it down with high overlap cams. My 2010 Camaro with the cam above seems to idle much rougher with 14-16° no matter what I do with the adaptive air tables.

Like to here your comments and have followed you on many threads. Especially the Idle threads. Thanks for the help you give everyone on this forum.

[DSteck]

Adaptive spark will do a lot more than adaptive airflow. That's where I'd look.

[Mike Norris]

Overspeed Coast being positive?

Ding ding. The more I looked into it, there is an issue with this BETA. There are two lines in both of my coast tables and they are actually tied somehow. I made the mistake of changing the lower line manually since it did not match and it threw off the other coast table. Very odd but glad I picked up on it.

DSteck,

I know that is what you prefer and can respect that, but I find that more timing with larger cams gives me a nicer idle also, similar to what Darin posted. Not saying one way is right or wrong, or one is better then the other, just two ways to do it.

Mike Norris

[edcmat-l1]

I know that is what you prefer and can respect that, but I find that more timing with larger cams gives me a nicer idle also, similar to what Darin posted. Not saying one way is right or wrong, or one is better then the other, just two ways to do it.

Mike Norris

I usually run 20-22 degrees of timing in the motors with bigger cams too. That combined with tweaking the over/under speed tables can really make them idle nicely. I hate that RUMP RUMP RUMP idle these things get from the aggressive over/under speed spark combined with the low idle timing.