LT1-LT4 Modifications 1993-97 Gen II Small Block V8

IAC didn't fix the problem with my idle

Thread Tools
 
Search this Thread
 
Old Jun 19, 2009 | 05:14 PM
  #1  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default IAC didn't fix the problem with my idle

My 93 trans am has been idling about 300-400 rpm high at about 1100-1200 rpm.

Everyone told me it was my IAC, so i shell out 75 dollars and it didn't help.
I tried the hold the gas when starting and wait 5 seconds, it didn't help.

I just screwed the little pin in a few threads and stuck it in, should I do something different?
Reply
Old Jun 19, 2009 | 05:16 PM
  #2  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

Originally Posted by Randal McSandal
My 93 trans am has been idling about 300-400 rpm high at about 1100-1200 rpm.

Everyone told me it was my IAC, so i shell out 75 dollars and it didn't help.
I tried the hold the gas when starting and wait 5 seconds, it didn't help.

I just screwed the little pin in a few threads and stuck it in, should I do something different?
Did you take your intake off and verify that the TB is actually closing all the way?
Reply
Old Jun 19, 2009 | 05:18 PM
  #3  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

I took the intake off, what do you mean by closing all the way?
The pin itself couldn't really be pushed by my finger.
Reply
Old Jun 19, 2009 | 05:19 PM
  #4  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

Originally Posted by Randal McSandal
I took the intake off, what do you mean by closing all the way?
The pin itself couldn't really be pushed by my finger.
The throttle body blades...are you sure the blades are closing all the way when you are not pushing the pedal?

I would also check your intake elbow, PCV hoses, brake booster hose, all vacuum and air hoses for leaks. A vacuum leak can cause a high idle.
Reply
Old Jun 19, 2009 | 05:20 PM
  #5  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

Not all the way, most the way.. is that the problem?
Reply
Old Jun 19, 2009 | 05:21 PM
  #6  
litch2004's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: May 2007
Posts: 1,781
Likes: 1
From: Austin
Default

yes it is. More air the higher the idle.
Reply
Old Jun 19, 2009 | 05:22 PM
  #7  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

Originally Posted by Randal McSandal
Not all the way, most the way.. is that the problem?
Huh? Did you adjust your TB blade stop screw? Yes the blades are supposed to close all of the way...unless you have a huge cam or something.
Reply
Old Jun 19, 2009 | 05:22 PM
  #8  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

I'm sorry I'm such a noob, I just thought that was correct, I just turned 17 lol.

How do I adjust these?
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-1

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-2

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-3

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

 Verdad Gallardo
story-4

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

 Pouria Savadkouei
story-5

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

 Verdad Gallardo
story-6

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-7

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-8

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-9

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

 Verdad Gallardo
Old Jun 19, 2009 | 05:22 PM
  #9  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

And no I just have intake/flomasters with del cat.
Reply
Old Jun 19, 2009 | 05:24 PM
  #10  
Speed Density's Avatar
hashtagBMW
iTrader: (38)
 
Joined: Jul 2005
Posts: 6,572
Likes: 2
From: Boise, Idaho
Default

Did you actualy see if your IAC was even the issue? Get yourself the free trial of TTS Datamaster and see if the IAC is functioning correctly, you could have other issues.

0 is fully open
160 is fully closed.
Reply
Old Jun 19, 2009 | 05:27 PM
  #11  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

http://shbox.com/1/accelerator_stop.jpg

Adjust that screw so that the blades close all the way. It's on the back of the TB by where the cable attaches. If you pull open the blades by hand, you should see the screw protruding to stop the lever at a certain point. You might have to remove the TB to do so. FYI, alot of TB gaskets will block this adj screw, so you might not see it.
Reply
Old Jun 19, 2009 | 05:29 PM
  #12  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

It turns out that the blades are closed, but it's not perfectly straight up and down, which I don't think that they could get that way am I right?
Reply
Old Jun 19, 2009 | 05:36 PM
  #13  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

Originally Posted by Randal McSandal
It turns out that the blades are closed, but it's not perfectly straight up and down, which I don't think that they could get that way am I right?
Try to get a hold of a scanner and verify your IAC counts and TPS voltage.

In the mean time, check for vacuum leaks like I stated above.
Reply
Old Jun 19, 2009 | 05:37 PM
  #14  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

How do I check for vac leaks?
Reply
Old Jun 19, 2009 | 05:37 PM
  #15  
DisturbedTA's Avatar
TECH Enthusiast
iTrader: (3)
 
Joined: Apr 2009
Posts: 572
Likes: 0
From: morristown,tn
Default

how about the tps that sounds like the problem
Reply
Old Jun 19, 2009 | 05:37 PM
  #16  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

I was thinking TPS, but someone said that didn't effect idle..?
Reply
Old Jun 19, 2009 | 05:39 PM
  #17  
litch2004's Avatar
TECH Fanatic
iTrader: (1)
 
Joined: May 2007
Posts: 1,781
Likes: 1
From: Austin
Default

Originally Posted by Randal McSandal
I was thinking TPS, but someone said that didn't effect idle..?
Whoever said that told you wrong. It has a lot to do with it.
Reply
Old Jun 19, 2009 | 05:44 PM
  #18  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

How can I adjust this?
Reply
Old Jun 19, 2009 | 05:45 PM
  #19  
ss.slp.ls1's Avatar
TECH Senior Member
15 Year Member
iTrader: (36)
 
Joined: Jan 2008
Posts: 8,184
Likes: 28
From: Orange County, CA
Default

Originally Posted by Randal McSandal
How do I check for vac leaks?
Look for holes visually. You can also spray starter fluid around your intake manifold at all the sealing surfaces and along all the vacuum lines. If there is a vacuum leak, when you spray at it, the idle will go up. Just don't go crazy and burn your engine down, lol.
Reply
Old Jun 19, 2009 | 05:53 PM
  #20  
Randal McSandal's Avatar
Thread Starter
On The Tree
iTrader: (3)
 
Joined: Jun 2009
Posts: 194
Likes: 0
From: Southern Indiana
Default

I think I found it, just to the left of the intake there's a 90* rubber elbow connected to a 6 inch tube, that fitting is absolutley shot. Would that be it?
Reply



All times are GMT -5. The time now is 02:53 AM.

story-0
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-1
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-2
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-3
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-4
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-5
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-6
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-7
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-8
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-9
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