PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Cold Start Idle Issue

Thread Tools
 
Search this Thread
 
Old Jul 29, 2013 | 12:19 PM
  #1  
HeavyArms SS's Avatar
Thread Starter
Teching In
iTrader: (4)
 
Joined: Feb 2013
Posts: 29
Likes: 0
From: AZ
Default Cold Start Idle Issue

I'm having issues with the cold start idle on my '99 Z28. When I first start it up it wants to die, the rpms fall really low and then I have to give it some gas just to keep it from stalling out. After a couple minutes of letting the car run it will settle it's idle in at 850 which is where it's supposed to be. It does not idle low at any other time.

The engine specs are: PRC Stage 2.5 5.3L CNC Ported Heads, Prc .650 dual springs, TSP Magic Stick 3 237/242 .603"/.609", 36# Precision Flow Injectors, LS6 Intake, BBK 85mm Throttle Body, SLP 85mm MAF & harness, LS7 Lifters, Chromoly Pushrods, LS6 Oil Pump, LS2 Timing Chain, !EGR, !AIR, SLP lid, and Pacesetter longtubes.

The car was dyno tuned by the previous owner at a shop in California. I cleaned the throttle body and IAC(which were pretty dirty) and it still idles bad on cold starts. I don't have a handheld tuner to get any readings from the engine. I took a video at cold start. Any suggestions? Thanks.

http://www.youtube.com/watch?v=ylhoq...ature=youtu.be
Reply
Old Aug 3, 2013 | 01:22 AM
  #2  
HeavyArms SS's Avatar
Thread Starter
Teching In
iTrader: (4)
 
Joined: Feb 2013
Posts: 29
Likes: 0
From: AZ
Default

Any ideas? I have a new IAC on the way and should have that next week.
Reply
Old Aug 3, 2013 | 07:09 AM
  #3  
Old Geezer's Avatar
TECH Senior Member
iTrader: (3)
 
Joined: Jun 2004
Posts: 5,639
Likes: 71
From: GA, USA
Default

A suggestion: With an engine w/ as many mods as you have......Buy a scan tool.
Or, find someone local that can scan and data log a cold start. Post the log[s], and the tune.
Otherwise, it's a guessing game.
Reply
Old Aug 10, 2013 | 10:03 PM
  #4  
MillsMotorvation's Avatar
TECH Fanatic
 
Joined: Jan 2010
Posts: 1,343
Likes: 2
From: South of Augusta,GA
Default

Got to get something to scan or tune with
Reply
Old Aug 11, 2013 | 02:25 PM
  #5  
HeavyArms SS's Avatar
Thread Starter
Teching In
iTrader: (4)
 
Joined: Feb 2013
Posts: 29
Likes: 0
From: AZ
Default

I replaced the IAC since the one that was in there was pretty sad looking and the o-ring was mostly deteriorated. I also replaced the SLP 85mm MAF with a stock one and it is a thousand times better. I guess the SLP unit just went bad.
Reply




All times are GMT -5. The time now is 03:11 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