C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette
Sponsored by:
Sponsored by:

Lopy idle +

Thread Tools
 
Search this Thread
 
Old Jan 29, 2014 | 09:54 PM
  #1  
Sayfoo's Avatar
Sayfoo
Thread Starter
Safety Car
Veteran: Army
20 Year Member
Liked
Community Favorite
 
Joined: Sep 2005
Posts: 4,213
Likes: 643
From: Orange County Ca
Default Lopy idle +

General question here.
As engine speed increases from idle (no load, in neutral), does the engine smooth out, or does it just seem so because of the higher rpm's.
My more or less stock 69 BB does not idle smoothly at all, and still runs rough up to about 2k rpm in neutral, where it significantly runs smoother. Normal or ?? Don't notice any significant off idle roughness while driving.
Reply
Old Jan 29, 2014 | 10:24 PM
  #2  
illenema's Avatar
illenema
Melting Slicks
10 Year Member
 
Joined: Oct 2007
Posts: 2,310
Likes: 9
From: KB7TIF Ville NV
Default

Might be running Rich on idle mixture. At about 2k the carb switches over the the main jets and no longer relies on idle mixture to run?
Lean up the idle mix a bit try that remember ware it was set

Last edited by illenema; Jan 29, 2014 at 10:28 PM.
Reply
Old Jan 30, 2014 | 09:15 AM
  #3  
Panhead59's Avatar
Panhead59
Racer
 
Joined: Sep 2012
Posts: 262
Likes: 0
From: Roanoke Va.
Default

The most common issue with rough idle on these year cars is a vacuum (spelling) leak. With so many lines, and usually old lines , and not always easy to find, vacuum leaks are a pretty common reason for rough idleing.
Reply
Old Jan 30, 2014 | 01:40 PM
  #4  
cardo0's Avatar
cardo0
Le Mans Master
20 Year Member
 
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
Default Tool box carb?

Do u have a spare good carb ready to swap and test? I would recommend this that way u can eliminate the carb as a problem or not right away. I dont know what kind of carb u have but the qjet gets quirky after sitting too long - float hangs up, evaporated fuel leaves deposits over long time. How is your fuel filter?

Disconnect or plug vac lines one at a time.

Are u still using points? If so inspect them.

Hope this helps,
cardo0
Reply
Old Jan 30, 2014 | 08:45 PM
  #5  
Sayfoo's Avatar
Sayfoo
Thread Starter
Safety Car
Veteran: Army
20 Year Member
Liked
Community Favorite
 
Joined: Sep 2005
Posts: 4,213
Likes: 643
From: Orange County Ca
Default

I run a q jet and I think it is jetted correctly (was dyno tuned years ago). Idle may be running rich. It is kinda stinky at idle. I was having overheating problem when I rebuilt the motor on this totally bubba'd car, so I think I let it run a little rich as I tracked down the overheating problem. I do run points, but ignition system seems to be working correctly. Vac advance is all in at about 2600 rpm. Plugs look good. I think the lopy idle is probably because of the slightly bigger than stock cam? I'll lean out the idle mixture.
Thanks for the ideas.
Reply

Get notified of new replies

To Lopy idle +





All times are GMT -4. The time now is 02:27 PM.

story-0
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-1
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-2
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-3
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-4
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-5
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-6
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-7
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-8
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE
story-9
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE