Any HP tuner guys in here ?

[switta]

tried to get some help over at hp tuners form but no luck ,
having an issue with the ls1 in my gtm when i come to a stop and push the clutch in and let off the throttle it want's to drop to around 300 rpm and sometimes stall out , if i hold throttle a bit till stopped then let off it will hold my 850 target idle just fine .
i am new to the hp tuners stuff and don't want to make any changes with not knowing what i am doing , i have saved my original tune to my lap top and flash drive to be safe .
been doing a lot of research on this and i think it comes down to throttle cracker and follower section of the tune , i think it is definitely a air flow issue not getting enough when coming to a stop ? have any of you guys worked with this tuning stuff or know anyone that could point me in the right direction .
if anyone has an hp tuner ls1 tune they could post i could compare mine to that would be a huge help to see how the tables are set up on yours .
other then the low idle issue when coming to a stop it runs great . i have my fuel tank issue fixed thanks to help from you guys here now if i can just get this idle issue solved i would be good to go .
one thing i found while while doing this is the vin for the ecu is for a 2002 ls6 but my block is an ls1 ? i have no idea why .

Dave s

[VRaptor SpeedWorks, LLC]

Any chance this is happening with the AC on? Are you running a donor C5 ECU or crate engine ECU?

[beeman]

Looks like he's running an 02 z06 ECU, which is same as the ls1 ECU with a different tune. Are you running the a/c compressor signal through the ECU or separate? Like Shane is saying, this problem usually occurs when the ECU isn't aware that the engine is seeing rotational drag from an active a/c compressor. Does it only occur when the a/c is on?

What modifications does your ls1 have? Cam?

[beeman]

If it does turn out that the problem only occurs when you have the a/c on, I would contact the builder of your car to see if he managed the a/c compressor through the GM ECU or separate, separate would usually be via a trinary switch.

[switta]

ac is off when it happens . have not ran the ac while driving yet , fans come on as soon as i turn ac on and idle increases slightly , i will have to try it while driving and see how it does then .
i am going to bump up the air flow in throttle cracker table in the 400 to 1600 rpm range by 10% and see if that helps ?

[dlud]

I had that problem when I went to a hotter cam in my LS6. Saved my original tune and edited to increase throttle to 900, flashed and all was good. Saved the edited tune as a new file.

[David Ferguson]

Usually you want to adjust (increase) the throttle cracker - this tells the ECU what the minimum throttle (or IAC valve) position to hold when the engine is above idle, this way when it returns to idle, there is some air to avoid a stall. You holding the throttle has the same effect.

[dlud]

Yes, found in "Engine", "Idle", "Base Setpoint."

[switta]

well per dlud suggestion i set base idle at 900 and i also went up only 5% on the throttle cracker airflow in the 400 to 1000 rpm range ( maybe not enough to do anything ) and no change still wanted to stall out last night , not sure how much i can increase air flow in the cracker setting ? i suppose if i add to much it will just idle to high . it's throwing no codes to give me any ideas what it may be ? think i will log a drive on the scanner and see what info i can get from that ?

Dave

[LCD Gauges]

If you can post/email the HPT file, I can have a look.

[switta]

Thanks LCD gauges , not sure how to attach file here ?
i did see my throttle cracker was disabled at 2mph and enable at 1 mph i changed it to enable at 2mph and disable at 1mph have not tried it yet . if i can figure how to attach that tune file here i will ?

[Presto51]

One more thing to look into if you can't find a solution, run out of ideas.

Check the Vehicle Speed Sensor.

Not an expert, but something to think about.

"Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth." Arthur Conan Doyle

Ron

[switta]

LCD gauges , sent you an e-mail with the tune .
thank you very much for the offer .
Dave s

[RR46]

I am pretty sure you have a light weight flywheel as we all do, and that's why this is happening on a stock LS1 tune. Not 100% sure of the correct solution in the tune but it has to do with the lack of natural momentum of a big heavy stock C5 flywheel as you slow down. The motor needs a little more help to run when it drops to idle, maybe a little change on the idle downward timing curve as the rpms come down, so the timing kicks in support a little sooner. Shouldn't be difficult at all. My tuner who cleaned up my torque limited LS1 tune missed it bc I forgot to mention it, it doesn't happen often. Will be watching and set this idle landing tune correctly on my LS7.

[switta]

yes RR46 sounds like your on the right track . LCD gauges has been very helpful and is also thinking it could use timing in those areas .
working on other parts of the car so when i get a chance i will change some timing settings and see how it does .
thanks for the reply guys ! really appreciate it .

Dave

[Shoeless]

I am not familiar with HP Tuners and just getting my feel wet on tuning my AEM Infinity, but found this article that may or may not help you. Maybe worth reading.

https://forum.hptuners.com/showthread.php?36318-Idle-Tuning-How-To-amp-Guide-(w-pictures)