Back Firing
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,562
Likes: 1
From: (Temporarily) Colorado Springs Colorado
Back Firing
Hello all :seeya ... been a long time since I have been on the forum. I have been very busy at work and broadcasting on our new Internet radio station RadioHeart.com
I've had quite a bit of work done on the 72 and seem to have picked up backfiring when I lift my foot off the gas. Also, it seems to be running a little rich now. I thought I saw someplace on the forum that backfiring could be caused by a vacuum leak or a leak in the intake manifold. Anyone have any suggestions as to what is causing this annoying problem?
Thanks....
[Modified by The Wanderer, 11:07 AM 7/6/2003]
I've had quite a bit of work done on the 72 and seem to have picked up backfiring when I lift my foot off the gas. Also, it seems to be running a little rich now. I thought I saw someplace on the forum that backfiring could be caused by a vacuum leak or a leak in the intake manifold. Anyone have any suggestions as to what is causing this annoying problem?
Thanks....
[Modified by The Wanderer, 11:07 AM 7/6/2003]
Racer
Joined: Sep 1999
Posts: 313
Likes: 0
From: New Lenox Il
Re: Back Firing (The Wanderer)
My 74 did that ayear or so ago. Only when I failed emmision test due to air leakage did I find out what it was. I had installed chambered exhaust myself and had leaks around where pieces slipped together. Had mechanic snug all up. tack welded a few spots. Wola...No more backfires. Leaks in intake manifold will also cause. also check timing. Good luck. Bob
Race Director
Joined: Jun 2001
Posts: 16,483
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From: The Only Corvette in Gila Bend, Az.
St. Jude Donor '09
Re: Back Firing (The Wanderer)
Hey everyone...look what the cat dragged in....It's the Wanderer :eek:
LONG time no see. How have you been? Me and BSeery were just talking about the a couple of weeks ago...
LONG time no see. How have you been? Me and BSeery were just talking about the a couple of weeks ago...
Team Owner
Joined: May 2001
Posts: 29,745
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
CI 6-7-8 Veteran
CI-VIII Burnout Champ
St. Jude Donor '06-'10, '13
Re: Back Firing (The Wanderer)
Welcome back stranger !!
Running rich and having a vacuum leak usually don't go hand in hand. A vacuum leak usually leads to a very lean condition. I think you can have popping in the exhaust from a lean condition as well. Best thing to do is to check the plugs to see if they are lean or rich.
If they are lean, then start tracking down the source of the vacuum leak. Old hoses and connections are a good bet. The vacuum system on an early C3 is a mess and you can get leaks from the wiper door system and the headlight actuators and all the connectors, valves, switches and every hose in between. Best bet is to put a vacuum gage on to the carb and disconnect all the other lines and plug them. Then plug each line in one at a time and watch the gage. This should tell you which system has the leak. From there move down that vacuum line pinching it shut with a pair of pliers and move along the system trying to isolate the problem.
If it's not in the accessory systems try first at the carb base gasket, and then look towards the intake manifold. If you've had either apart recently this could be a good start.
Let us know what you find out and stop being such a stranger. We all have busy lives, but we all end up here from time to time.
Good luck - and when I can I do listen to your show.
Running rich and having a vacuum leak usually don't go hand in hand. A vacuum leak usually leads to a very lean condition. I think you can have popping in the exhaust from a lean condition as well. Best thing to do is to check the plugs to see if they are lean or rich.
If they are lean, then start tracking down the source of the vacuum leak. Old hoses and connections are a good bet. The vacuum system on an early C3 is a mess and you can get leaks from the wiper door system and the headlight actuators and all the connectors, valves, switches and every hose in between. Best bet is to put a vacuum gage on to the carb and disconnect all the other lines and plug them. Then plug each line in one at a time and watch the gage. This should tell you which system has the leak. From there move down that vacuum line pinching it shut with a pair of pliers and move along the system trying to isolate the problem.
If it's not in the accessory systems try first at the carb base gasket, and then look towards the intake manifold. If you've had either apart recently this could be a good start.
Let us know what you find out and stop being such a stranger. We all have busy lives, but we all end up here from time to time.
Good luck - and when I can I do listen to your show.
Thread Starter
Melting Slicks
Joined: Feb 2001
Posts: 2,562
Likes: 1
From: (Temporarily) Colorado Springs Colorado
Re: Back Firing (BSeery)
Thanks for all the advice ... I had an exhaust leak ... the doughnut between the left manifold and tailpipe was blown ... so I didn't drive the 72 for several months. Got it replaced, along with a whole new shifter, and a few more repairs and the 72 is on the road again.
I will check all the vacuum lines, timing and other suggestions as well, and tell you what I discovered.
I will check all the vacuum lines, timing and other suggestions as well, and tell you what I discovered.
