Generation III External Engine LS1 | LS6 | Bolt-Ons | Intakes | Exhaust | Ignition | Accessories
Sponsored by:
Sponsored by:

High RPM Idle

Thread Tools
 
Search this Thread
 
Old Mar 11, 2016 | 06:33 PM
  #1  
gccasper04's Avatar
Thread Starter
12 Second Club
iTrader: (4)
 
Joined: Feb 2004
Posts: 176
Likes: 0
From: Arkansas
Default High RPM Idle

A little background on the car. Lq9 408 with f1a procharger. Ls6 intake. Lines are capped on throttle body that im not using. When first crank car, it will hold idle at 1800-2000. Then slowly idle down, i can bearly touch throttle, registers 2% when I logged it and it will soar back up and hols and after 15-20 seconds come down. It will rwpeat this for a couple minutes. Then it will go back to normal. I thought it was a temp related thing but even if you kill the car at operating temp and crank it right back it will do it. I pulled the IAC and sprayed the TB down and wiped it out. Any other ideas? Im open for anything.
Reply
Old Mar 11, 2016 | 07:30 PM
  #2  
gccasper04's Avatar
Thread Starter
12 Second Club
iTrader: (4)
 
Joined: Feb 2004
Posts: 176
Likes: 0
From: Arkansas
Default

Nobody...
Reply
Old Mar 11, 2016 | 07:37 PM
  #3  
JakeFusion's Avatar
Super Hulk Smash
20 Year Member
Liked
Loved
Community Favorite
iTrader: (7)
 
Joined: Aug 2004
Posts: 11,258
Likes: 146
From: Pace, FL
Default

Vacuum leak? Is it tuned?

If tuned, your running airflow is way too high most likely or your TB is too open. It's a bit of a chasing your tail to get your TB open just enough to get your IAC counts in the 60-80 range hot at idle. But something in the .55v range would be a good place to start for TPS voltage at 0% postion.

Once you get that, set your running airflow by starting the car and warming it up without touching the gas and logging it. You may need to adjust the TB after doing this if our IAC counts are off. Thus, rinse and repeat until you can get IAC counts right with the proper RAF.

Once that's adjusted, you can re-tune the bottom of the VE table to dial it in. You may also need to adjust your throttle cracker and follower tables since they control how much the IAC opens on throttle open and how fast it closes on throttle shut.
Reply
Old Mar 12, 2016 | 12:56 AM
  #4  
gccasper04's Avatar
Thread Starter
12 Second Club
iTrader: (4)
 
Joined: Feb 2004
Posts: 176
Likes: 0
From: Arkansas
Default

Originally Posted by JakeFusion
Vacuum leak? Is it tuned?

If tuned, your running airflow is way too high most likely or your TB is too open. It's a bit of a chasing your tail to get your TB open just enough to get your IAC counts in the 60-80 range hot at idle. But something in the .55v range would be a good place to start for TPS voltage at 0% postion.

Once you get that, set your running airflow by starting the car and warming it up without touching the gas and logging it. You may need to adjust the TB after doing this if our IAC counts are off. Thus, rinse and repeat until you can get IAC counts right with the proper RAF.

Once that's adjusted, you can re-tune the bottom of the VE table to dial it in. You may also need to adjust your throttle cracker and follower tables since they control how much the IAC opens on throttle open and how fast it closes on throttle shut.
What could possibly be leaking?

I know my tps is at .38v at 0% and doesnt move when the car goes into ita fits
Reply




All times are GMT -5. The time now is 09:43 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE