Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Something very wrong

Thread Tools
 
Search this Thread
 
Old Jun 5, 2004 | 09:40 PM
  #1  
Orange Juice's Avatar
Thread Starter
TECH Fanatic
20 Year Member
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,223
Likes: 2
From: Hamilton Ontario
Default Something very wrong

Had H/C installed last week
AS 5.3's and a 224 cam. CompR lifter, Yella Terra rockers. Car has TPIS headers/Ypipe, ported intake and 78mm tb. High fow heads M6 342 gears stock rearend.
Was told that the ported intake had a crack in it, but was repaired before the car was dyno tuned.
On the drive home, after I opened it up a couple of times the idle would hold at 3000 rpm's. I would hold my foot down on the clutch and the car would stay at 3000 rpm. I bought some plumbers patch and jammed it over the intake the idle dropped. got home cleaned it up and epoxied it again.
headed to the strip ran a best of 12.90 at 112 mph. Intake seem to start leeking again. Switched the intake back to the stock ls6, Car does the same thing.
So now the only other two things that I can think of is the tune is very off because the first tune had to correct the leak, or the compR's are not setup correctly.
I pulled a valve cover off and rotated the lifters and tried to see if there was any play. Couldn't find any play in the rockers at all.
Has anyone had this happen, is it the tune.
The car dynoed 395rwhp 375tq
Reply
Old Jun 5, 2004 | 09:52 PM
  #2  
HOTROD98Z's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Oct 2002
Posts: 1,042
Likes: 0
From: Molino, FL
Default

It sounds like there may be too much air getting past the blade of the TB and it's throwing the IAC sensor off. Is the stock hole still in the blade of the TB?
Reply
Old Jun 5, 2004 | 10:44 PM
  #3  
Orange Juice's Avatar
Thread Starter
TECH Fanatic
20 Year Member
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,223
Likes: 2
From: Hamilton Ontario
Default

The hole in the tb is larger then stock. I was going to switch back to the stock tb tomorrow
Reply
Old Jun 5, 2004 | 11:51 PM
  #4  
strokedls1's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Nov 2002
Posts: 1,829
Likes: 0
From: Venice, Ca
Default

Check the idle control plunger in the tb. If it is not working right it can cause the high idle.
Reply
Old Jun 6, 2004 | 05:37 AM
  #5  
Orange Juice's Avatar
Thread Starter
TECH Fanatic
20 Year Member
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,223
Likes: 2
From: Hamilton Ontario
Default

Would this have any effect on the HP of the car?
Reply
Old Jun 6, 2004 | 08:10 AM
  #6  
mike m's Avatar
TECH Fanatic
iTrader: (6)
 
Joined: Nov 2001
Posts: 1,101
Likes: 0
From: Las Vegas
Default

you better check your preload, that is the most important thing, you dont want to colllapse a lifter.
Reply
Old Jun 6, 2004 | 08:29 AM
  #7  
Orange Juice's Avatar
Thread Starter
TECH Fanatic
20 Year Member
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,223
Likes: 2
From: Hamilton Ontario
Default

Without having to get to the timing set to get tdc, is there some way of checking the preload. If there was too much load on the rockers wouldn't that hold the valves open?
Reply
Old Jun 6, 2004 | 02:55 PM
  #8  
strokedls1's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Nov 2002
Posts: 1,829
Likes: 0
From: Venice, Ca
Default

The idle plunger will have no effect on power output of the car. If the preload is too great it can cause valves to hang open a little bit. You need to redo those if they are a problem before the lifters are destroyed.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

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

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Jun 6, 2004 | 04:24 PM
  #9  
Orange Juice's Avatar
Thread Starter
TECH Fanatic
20 Year Member
iTrader: (3)
 
Joined: Mar 2003
Posts: 1,223
Likes: 2
From: Hamilton Ontario
Default

I pulled the idle plunger out and connected it and turned the ignition on and off. the plunger moves back and forth. I will get a new one tommorrow. I switched back to the stock tb and that seemed to make a difference. The idle wouldn't hold high for very long but still not rite.
As far as checking the load on the lifters, should I just rotate the engine until I see both valves closed. I was going to stick a piece of coat hanger wire down the spark plug hole but was worried that it might get stuck under a valve.
If the valves were open a bit wouldn't there be some sign of this?
Reply
Old Jun 6, 2004 | 05:36 PM
  #10  
strokedls1's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: Nov 2002
Posts: 1,829
Likes: 0
From: Venice, Ca
Default

A leak down test would tell you if the valves were hanging open. If they were all a problem the car wouldn't run. Sounds like there is still some unmetered air getting into the intake if you swapped tb's and it is still idleing high. Take off the serpentine belt and turn the motor over with a breaker bar with 24mm after removing the plugs. Rotate the engine until just after both valves are closed on each cylinder. Then loosen them and retorque and check how much of turn it takes to 22 ftlb.
Reply




All times are GMT -5. The time now is 09:00 PM.

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