Where to start? Neutral Coasting / Hanging Idle

[badazz81z28]

Gents,

When my car is warmed up driving around; I put my car in neutral and coast it will rev to 1500 rpms. Once I come to a complete stop, it will continue to stay at 1500 rpms for about 8 secs than drop to normal RPMs.

My car has already been dyno tuned using a wideband, so I don't want to mess that up. Other than that issue, it idle perfect, starts up warm and cold perfect...just this one annoying issue. Its an LS6 with a 228R cam / 5 speed manual tranny.

Here is a video

http://www.youtube.com/watch?v=6tKzx...ature=youtu.be




Where so I start? First time using HPT

[badazz81z28]

Folks, BTW, only does it when the engine is up to operating temps.

[Pekka_Perkeles]

Post your tune. Or try it quick and dirty way by decreasing Base Running Airflow values a bit from the current values. If you decrease too much, well, You'll notice that quite fast...

[JamesLinder]

you could have the throttle body butter fly screw adjusted to far open at idle and the IAC motor is then unable to
reduce air flow quickly enough for a good idle. Or, if you set the idle air with IAC parked (before starting) I have
seen this cause the same thing. And as Pekka pointed out, if you have your RAF air too high at typical operating
ECT this will also cause this same problem. Yes, please post your tune and someone will be able to give you more
specific advice.

[badazz81z28]

Anyone? Please help

[badazz81z28]

Log attached:

[badazz81z28]

Here is a better log. Looks at though the IAC is doing what it's commanded to do. I don't see why the counts should be so high while driving....

[badazz81z28]

Anyone???

I guess whats is really mind boggling , it doesn't act this way all the time! Someone has to know...What commands high IAC counts?

[gagliano7]

I have a 5.3 with a lunati 212/218 cam and mine works perfect. You can look at my tune to compare to yours. My pcm is a 1999. Also do a search for Russ k idle config to get you base idle airflow correct.

[Philvcm]

hey mate by the sound of that you have to much base running airflow in that area according to temp. put it back to stock, and dont be scared but drill a 3 mm hole in the butterfly softly so it doesnt warp the throttle plate. rember factory ls1 has a hole in the butterfly.

[badazz81z28]

hey mate by the sound of that you have to much base running airflow in that area according to temp. put it back to stock, and dont be scared but drill a 3 mm hole in the butterfly softly so it doesnt warp the throttle plate. rember factory ls1 has a hole in the butterfly.

I zero'd out the throttle cracker table...Still hangs

Used the Idle config....Dies, but still hangs when warmed up


The key is...It doesn't hang all the time!!! I think it has a lot to do with the temps outside...I'm lost...Help.

[JamesLinder]

I would need to see your TUNE file to see if I see anything that looks out of line. I do not care about your log files that you posted.
Mine works best with reduced timing in the main spark tables to prevent cruising, and I have learned that you should not have to
zero out throttle cracker air if you have all the other parameters in your tune calibrated correctly, such as MAF and VE. If you want
further help, POST YOUR TUNE (the .hpt file)!

[badazz81z28]

I would need to see your TUNE file to see if I see anything that looks out of line. I do not care about your log files that you posted.
Mine works best with reduced timing in the main spark tables to prevent cruising, and I have learned that you should not have to
zero out throttle cracker air if you have all the other parameters in your tune calibrated correctly, such as MAF and VE. If you want
further help, POST YOUR TUNE (the .hpt file)!

[edcmat-l1]

Looking at the tune will only tell you so much. You can't see if the blade is open too far, or if the hole in the blade is too big, etc. I've always preferred a data log with the proper pids, so you can see where the air is coming from, and position of the IAC. That will usually tell you a lot more.

As for the tune, the idle air is not that high at all. I would assume there's unwanted air coming from somewhere. Blade open too far, hole too big, air leak, etc.

[2xLS1]

There is less idle air than in a stock file. The fact that it idles with that low of an idle air table and a 228 cam suggests a mechanical issue like edcmat-11 said. The Throttle Cracker table seems odd. I would zero out the first two columns too.

[badazz81z28]

There is less idle air than in a stock file. The fact that it idles with that low of an idle air table and a 228 cam suggests a mechanical issue like edcmat-11 said. The Throttle Cracker table seems odd. I would zero out the first two columns too.

Are you talking about the base running airflow? What sort of mechanical issue? MY set-up is 100% brand new.

Yes it idles fine, just the random hang.

[badazz81z28]

Looking at the tune will only tell you so much. You can't see if the blade is open too far, or if the hole in the blade is too big, etc. I've always preferred a data log with the proper pids, so you can see where the air is coming from, and position of the IAC. That will usually tell you a lot more.

As for the tune, the idle air is not that high at all. I would assume there's unwanted air coming from somewhere. Blade open too far, hole too big, air leak, etc.

We have ran the log. It shows the air is coming in from the IAC. When the idle hangs, the IAC counts are in the 100s, idle is around 40.

[badazz81z28]

Hey guys, that's the wrong tune. That's what the "idle config" thingy told me to set it to. It wouldn't run good like that lol..

Here is the right one.

[gagliano7]

When you do your idle config change your settings for desired idle to 4 decimal so you get a more precise numbers.

[badazz81z28]

When you do your idle config change your settings for desired idle to 4 decimal so you get a more precise numbers.

Well, I swapped out the IAC today with a genuine part and it still "randomly" hangs. IAC counts are 130ish while hanging and drop to 33 for idle. Why would the IAC be told to stay open?? and at Random???