LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

backfiring/popping while decelerating

Thread Tools
 
Search this Thread
 
Old Jan 28, 2008 | 07:12 PM
  #1  
LearJet's Avatar
Thread Starter
Registered User
 
Joined: Jul 2007
Posts: 459
From: Daytona Beach, FL
backfiring/popping while decelerating

When I get off the gas I hear what sounds like the exhaust popping and backfiring but it almost sounds like a chassis noise. I had it up on the lift today and for the life of me I don't see anything that could be rattling around so I am lead to believe it is indeed coming from the exhaust. I pressurized my exhaust system while I was at it and found no leaks minus a pinhole in one of the welds way back ny the rear end. The noise seems to emminate from the front left of the car. It is kinda hard to tell the car is kinda noisy anyways. Any ideas as to what may cause this?
Old Jan 28, 2008 | 08:24 PM
  #2  
SS RRR's Avatar
Registered User
 
Joined: Oct 1998
Posts: 3,144
From: Jackstandican
Originally Posted by LearJet
When I get off the gas I hear what sounds like the exhaust popping and backfiring but it almost sounds like a chassis noise.
Can you feel anything when it happens?
Old Jan 28, 2008 | 08:30 PM
  #3  
porksoda's Avatar
Registered User
 
Joined: Mar 2005
Posts: 439
From: Clovis, New Mexico
As long as its not like a gunshot or anything you should be good. Our cars are known to gurgle and burp on deceleration, my car does it too.
Old Jan 28, 2008 | 08:32 PM
  #4  
flynlow's Avatar
Registered User
 
Joined: Nov 2007
Posts: 107
From: Cincinnati, OH
With a stock exhaust mine does it too I kinda like it
Old Jan 28, 2008 | 08:47 PM
  #5  
mrmint69's Avatar
Registered User
 
Joined: Oct 2006
Posts: 2,731
From: Post Falls, Idaho
Happens a lot and not many answers why. I guessed it was from some sort of leak somewhere.
Old Jan 28, 2008 | 08:53 PM
  #6  
jay_rich's Avatar
Registered User
 
Joined: Nov 2007
Posts: 811
From: Windsor, ON Canada
Mine does it too...I belevie i have an exhaust leak and my wideband is saying like 10.9:1 during WOT so im running rich.

My old Kawasaki Zx6R did it when i put a carbon fiber pipe on i loved it

Jay
Old Jan 28, 2008 | 10:09 PM
  #7  
LearJet's Avatar
Thread Starter
Registered User
 
Joined: Jul 2007
Posts: 459
From: Daytona Beach, FL
Well I don't like it, yeah you can kinda feel it in the floorboard. I want it to go away. Or at least quiet it to a dull roar. It most definatly sounds like unburnt fuel popping in the headers. But why is their unburnt fuel in their in the first place and what do I need to adjust in my PCM to make it go away? More timing in the decel cells? anyone with a possible solution feel free to chime in.
Old Jan 28, 2008 | 10:23 PM
  #8  
RKPsk8er's Avatar
Registered User
 
Joined: Aug 2006
Posts: 649
From: Fayetteville, GA
ive been told that the popping is a result of unburned fuel igniting inside the cat. I've also heard this can damage the inside of the cat
Old Jan 28, 2008 | 11:41 PM
  #9  
Fatdog2's Avatar
Registered User
 
Joined: Oct 2007
Posts: 1,174
Doesn't the air pump fix this?I dunno,I sell furniture.Anybody else?
Old Jan 28, 2008 | 11:47 PM
  #10  
LearJet's Avatar
Thread Starter
Registered User
 
Joined: Jul 2007
Posts: 459
From: Daytona Beach, FL
Do any of you people read before you post? If you read my sig you would see I have no cat nor do I have an AIR pump. If you do not have anything helpful please do not post.
Old Jan 29, 2008 | 12:59 AM
  #11  
SS RRR's Avatar
Registered User
 
Joined: Oct 1998
Posts: 3,144
From: Jackstandican
Check your LCA's. Make sure they're tight. It's possible if it's a chassis "clunK" it could be LCA bushings. You might even have a torn tranny mount. Do you notice the shifter move during accel/decel? You shouldn't really feel a backfire through full exhaust.
Old Jan 29, 2008 | 01:03 AM
  #12  
Klypto's Avatar
Registered User
 
Joined: May 2002
Posts: 1,418
From: New Orleans, LA
if it does sound like a gunshot... what would cause that? i rarely drive mine anymore and its acting up like that
Old Jan 29, 2008 | 02:13 AM
  #13  
TheAutumnMonths's Avatar
Registered User
 
Joined: Nov 2007
Posts: 16
From: Redford, MI
Originally Posted by LearJet
Do any of you people read before you post? If you read my sig you would see I have no cat nor do I have an AIR pump. If you do not have anything helpful please do not post.
You people? What's that supposed to mean? Anyway, I get it too. I have shorty headers, and 3 in. exhaust... Why - I'm not sure, but like you I want it to stop! Also, to me sigs are like commercials. I just don't pay attention unless there are pretty pictures!
Old Jan 29, 2008 | 04:19 AM
  #14  
mrmint69's Avatar
Registered User
 
Joined: Oct 2006
Posts: 2,731
From: Post Falls, Idaho
Well here are some more posts to read.
https://www.camaroz28.com/forums/sho...light=backfire
https://www.camaroz28.com/forums/sho...light=backfire
Mostly more questions and little answers.
Old Jan 29, 2008 | 04:28 AM
  #15  
Zepher's Avatar
Registered User
 
Joined: Jul 2000
Posts: 1,880
From: Norfolk, VA. USA
I got a lot of decel pop on my car as well. I have an ORY and have a Borla Adjustable exhaust and when I had the Borla fully opened, it would pop loud and often. Now that I closed it up and send all of the exhaust through the muffler, it doesn't pop as often or as loud.



All times are GMT -5. The time now is 03:33 AM.