Exhaust noise

Reply Subscribe

Thread Tools

Search this Thread

Mar 16, 2019 | 02:51 PM

Auggievf

Thread Starter

Instructor

Joined: Nov 2012

Posts: 164

Likes: 16

From: Sacramento CA - California

Exhaust noise

I started my car to let it idle while working in the weatherstripping and I noticed that it had started making a popping noise. If I wait a few minutes and give it some gas, the carb makes a lot popping bang noise.... Thoughts?

Mar 16, 2019 | 04:22 PM

cabman72

Pro

Joined: Jan 2017

Posts: 653

Likes: 51

From: Beaver County PA

Vacuum leak or disconnected vacuum line would be my first guess if its popping out the exhaust. If its popping thru the carb I would check timing or a valve issue. You may also have a bad float/seat in the carb and its pouring too much gas into the engine.

Mar 17, 2019 | 03:01 AM

sug

Drifting

Joined: Aug 2013

Posts: 1,263

Likes: 512

From: perth Aus w.a

2020 Corvette of the Year Finalist (stock)

C3 of Year Winner (stock) 2019

Quote:

Originally Posted by cabman72

Mar 17, 2019 | 10:44 AM

stingr69

Le Mans Master

Joined: Mar 2004

Posts: 7,499

Likes: 1,507

From: Little Rock AR

Misfire (afterfire) makes popping out exhaust at idle. Fouled plug or maybe a plug wire shorting out/burnt on manifolds would be good thing to look for.

Misfire out carb (backfire) could be timing or just lean. Probably not lean if it is just idling. Backfire in carb under load could be a cam going bad. Backfire as you step on the gas would be more consistent with lean accelerator circuit.

Mar 17, 2019 | 11:43 AM

Auggievf

Thread Starter

Instructor

Joined: Nov 2012

Posts: 164

Likes: 16

From: Sacramento CA - California

Thanks all. It was running fine before the rain the past few months and now it's backfiring.... Blargh....

Mar 17, 2019 | 01:12 PM

cabman72

Pro

Joined: Jan 2017

Posts: 653

Likes: 51

From: Beaver County PA

Also check for a cracked distributor cap.

Mar 26, 2019 | 08:16 PM

Jstan2014

Safety Car

Joined: Mar 2014

Posts: 3,558

Likes: 548

From: Round Rock Texas

I’m curious if the cause of the popping noise has been determined?

Apr 2, 2019 | 07:50 PM

Auggievf

Thread Starter

Instructor

Joined: Nov 2012

Posts: 164

Likes: 16

From: Sacramento CA - California

Quote:

Originally Posted by Jstan2014

I’m curious if the cause of the popping noise has been determined?

Unfortunately no... I was in Florida this last week for Ultra Miami. Maybe I can figure it out on Sunday if we actually get some sun for once....

Thanks for asking!!!