C3 General General C3 Corvette Discussion not covered in Tech
Sponsored by:
Sponsored by:

Engine popping

Thread Tools
 
Search this Thread
 
Old Jul 7, 2015 | 09:42 PM
  #1  
Almora's Avatar
Almora
Thread Starter
5th Gear
 
Joined: Jul 2015
Posts: 5
Likes: 0
Default Engine popping

So I took my 78 standard on the first longer road trip this weekend. It seemed to be running good. When I stepped it down at freeway speed the engine made a couple loud pops from under the hood like a backfire. It did this two or three times. Any ideas?
Reply
Old Jul 7, 2015 | 09:43 PM
  #2  
diehrd's Avatar
diehrd
Safety Car
 
Joined: Jan 2009
Posts: 4,000
Likes: 299
From: New York
Default

A lean mixture pops out exhaust
Reply
Old Jul 8, 2015 | 01:42 PM
  #3  
gungatim's Avatar
gungatim
Burning Brakes
15 Year Member
All Eyes On Me
Liked
Loved
 
Joined: Apr 2008
Posts: 1,222
Likes: 93
From: shelbyville West Michigan
Default

lean or possibly pinging? is your timing correct? maybe someone put popcorn kernels on the exhaust manifold : )
Reply
Old Jul 8, 2015 | 10:20 PM
  #4  
Almora's Avatar
Almora
Thread Starter
5th Gear
 
Joined: Jul 2015
Posts: 5
Likes: 0
Default

Originally Posted by gungatim
lean or possibly pinging? is your timing correct? maybe someone put popcorn kernels on the exhaust manifold : )
I do love me some popcorn! It's more of a backfire. I'll check the timing. The car sat for 10 yrs and I suspect that may be causing a few issues. I threw in plugs and wires. Maybe a carb rebuild?
Reply
Old Jul 9, 2015 | 11:38 AM
  #5  
TimAT's Avatar
TimAT
Le Mans Master
15 Year Member
Liked
Loved
 
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
Default

Bad plug wire, bad distributor cap/rotor, swapped plug wires, valve train problems. You already did plugs and wires, just go on down the list.
Reply
Old Jul 9, 2015 | 09:47 PM
  #6  
Peterbuilt's Avatar
Peterbuilt
Le Mans Master
15 Year Member
 
Joined: Aug 2006
Posts: 7,426
Likes: 1,559
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Default An easy fix!

Originally Posted by diehrd
A lean mixture pops out exhaust
I agree, try turning both idle mixture screws OUT 1/4 to 1/2 turn.
Reply
Old Jul 9, 2015 | 09:54 PM
  #7  
BPHORSEGUY's Avatar
BPHORSEGUY
Melting Slicks
15 Year Member
Liked
Loved
Top Answer: 1
 
Joined: Jul 2010
Posts: 2,762
Likes: 820
From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Default

Replace the cap and rotor, if that turns out not to be the problem it's still cheap insurance. If that is the problem and you keep driving you'll be on the hook soon enough!
Reply

Get notified of new replies

To Engine popping





All times are GMT -4. The time now is 06:37 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