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

Engine racing, need thoughts.

Thread Tools
 
Search this Thread
 
Old Apr 11, 2017 | 07:58 PM
  #1  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default Engine racing, need thoughts.

So we have completed our move and after many delays 2 of my cars were dropped off today while I was at work. Now this car drove out of my old homes garage and down the driveway and to the truck with zero issues. When I got home my wife explained that the 2 characters that delivered them said that the white one doesn't run right. When I arrived home it looks as if someone was doing burnouts in my driveway. My wife knew I was about to flip. Anyway the car starts fine but immediately races to near 3000rpm and will not idle down, now they say they didn't drive it anywhere yet for some reason I have visions of the parking attendant in The Ferris Bueller movie. It is just a base 77 with a nothing special 350 and a Holley carb. I did find a broken vac line that appeared to be not recent. Not wanting to make any drastic changes the only thing I did was adjust one throttle adj screw 2 turns, it didn't help so I put it back to where it was. Then I started it in neutral and everything was back to normal and it seems fine now starting in neutral or park. Any thoughts or ideas would be greatly appreciated. Sorry for the long winded story.
Reply
Old Apr 11, 2017 | 09:04 PM
  #2  
TOM B1's Avatar
TOM B1
Burning Brakes
15 Year Member
 
Joined: Oct 2003
Posts: 836
Likes: 26
From: Harrisburg Pa
Default

Broken vacuum lines will do just what you said it was doing so you probably fixed it.
To bad you did not right down the miles, you would know if they ran it because its only a few feet to unload from trailer.
Reply
Old Apr 12, 2017 | 06:41 AM
  #3  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default

Thanks, I thought the same thing. The only thing that seemed odd to me on the vac line was that it had been just taped over on the end, there is no other half that I've found yet. The tape appeared to be quite old. After plugging the end and starting it it still did the same thing.
Reply
Old Apr 12, 2017 | 02:03 PM
  #4  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,734
Likes: 2,582
Default

a small diameter broken vacuum line will not cause a 3K idle speed. You have a Holley but make no mention as to which one and more importantly what kind of choke mechanism. What is your normal cold fast idle after setting the choke by stepping on the gas and then starting without touching the gas peddle again?
Reply
Old Apr 12, 2017 | 02:22 PM
  #5  
Alan 71's Avatar
Alan 71
Team Owner
15 Year Member
Active Streak: 120 Days
Community Influencer
Top Answer: 5
 
Joined: Sep 2006
Posts: 31,271
Likes: 4,362
From: Westminster Maryland
Default

Hi d,
I agree with MW and would look at the choke linkage and operation, and also the accelerator linkage.
Regards,
Alan
Reply
Old Apr 12, 2017 | 08:29 PM
  #6  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default

Originally Posted by MelWff
a small diameter broken vacuum line will not cause a 3K idle speed. You have a Holley but make no mention as to which one and more importantly what kind of choke mechanism. What is your normal cold fast idle after setting the choke by stepping on the gas and then starting without touching the gas peddle again?
Will there be info on the carb itself? Or possibly a picture?
Reply
Old Apr 13, 2017 | 11:55 AM
  #7  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,734
Likes: 2,582
Default

the front of the airhorn, the area of the carburetor where the choke blade pivots, has a list# of the carburetor.
Reply
Old Apr 13, 2017 | 07:49 PM
  #8  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default

The only # I see is 7445 with a 4 under it. Does that sound right? Here are a few pics of it. For the past 2 days now I can start it by giving it 2 pumps of the pedal, it fires right up idles normal and seems like it always did. This may sound bizzare but it literally seemed like when it happened as if you were holding the pedal to the floor yet it wasn't and none of the linkage was bound up. If it makes any difference the car went from western NY to south FL so quite a difference in altitude.
Attached Images    
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-1

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-2

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-3

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-4

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-5

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-6

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-7

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-8

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

 Joe Kucinski
story-9

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
Old Apr 14, 2017 | 12:24 PM
  #9  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,734
Likes: 2,582
Default

the part with the number on it is the metering block. Look at the vertical surface behind it, that is the airhorn and it should have a number on it.
The other pictures show that you have an electric choke and the fast idle cam could have been stuck but 3k sounds high for a choke fast idle.
You may never determine the cause if it was a one time event.
Reply
Old Apr 14, 2017 | 07:58 PM
  #10  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default

I'm leaning towards never knowing what occurred. I really appreciate your input and thoughts. My last question may seem off the wall, we moved from western NY to South Florida which is a drastic change in altitude, might that have had any impact on things?
Reply
Old Apr 15, 2017 | 09:48 AM
  #11  
MelWff's Avatar
MelWff
Race Director
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2006
Posts: 18,734
Likes: 2,582
Default

That would not have anything to do with your problem.
Reply
Old Apr 15, 2017 | 09:26 PM
  #12  
diehrd's Avatar
diehrd
Safety Car
 
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Default

Disconnect the throttle cable , or manually move the throttle and be SURE it stops closed as it should. Not to be rude but the motor looks un-kept . I would check ALL vac lines for dry rot based on what I see in that limited photo
Reply
Old Apr 16, 2017 | 06:56 AM
  #13  
danh77's Avatar
danh77
Thread Starter
Pro
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2014
Posts: 570
Likes: 65
From: Sebastian,FL
Default

Originally Posted by diehrd
Disconnect the throttle cable , or manually move the throttle and be SURE it stops closed as it should. Not to be rude but the motor looks un-kept . I would check ALL vac lines for dry rot based on what I see in that limited photo
No worries, I didn't take it as rude. The motor is completely void of any eye appeal. Amazingly it runs like a scalded dog, so I've put more thought into what will replace it instead of any beautification of it as it's not the original motor. Back to the subject though, throttle is working properly and vac lines repaired, car is running fine again and I've chalked the entire experience up to something I'll never find the answer to.
Reply

Get notified of new replies

To Engine racing, need thoughts.





All times are GMT -4. The time now is 06:32 PM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
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-9
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