Backfire during decelleration

[ron wilson]

I have a74 MGB that backfires a lot during decelleration. Is this a sign that the mixture is too rich. Mufflers are shot also.

 

[David_DuBois]

It's a sure sign that you have an air leak in the exhaust. Unburned fuel + air + spark = bang!
Cheer,

 

[dklawson]

As mentioned, you have an exhaust leak. Don't limit your search for it by looking at the muffler. Look for perforations in the pipes, leaks at the pipe joints, and the flanges to the cylinder head. It's amazing how sealing all those minute leaks can make backfiring on decel go away.

 

[vping]

Say your system was intact without holes. Might you get some backfiring during deceleration?

 

[77v8]

Had the same problem as you, turned out to be the gulp valve was bad.Do you still have the smog stuff on?

 

[Billm]

Yep- mine was the gulp valve too. Finished removing ALL of the smog stuff and the backfiring stopped.
Bill

 

[ron wilson]

Thanks for the help. Do not have any smog equip on the car but definitely have a leak in the header pipe.

 

[Nunyas]

problem solved! a leak inna exhaust! NEXT! /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

 

[DrEntropy]

Now we can completely divert THIS thread! /bcforum/images/%%GRAEMLIN_URL%%/devilgrin.gif

 

[Nunyas]

i painted a wheel today...

 

[Deleted member 3577]

I'm considering replacing my analog Lucas flasher relay with a solid state look alike....

Will this psychologically damage my car's ego?

 

[Nunyas]

I'm not sure... would you take an ego hit if you had a pace maker installed? /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

 

[DrEntropy]

Voluntarily?

...I think not. /bcforum/images/%%GRAEMLIN_URL%%/smirk.gif

 

[Bugeye58]

I'm not sure... would you take an ego hit if you had a pace maker installed? /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

Better a pacemaker than installing a Pacesetter.
Jeff

 

[Deleted member 3577]

i painted a wheel today...

I'm not sure... would you take an ego hit if you had a pace maker installed? /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

Maybe I would if someone told me I needed to wear new makeup /bcforum/images/%%GRAEMLIN_URL%%/whistle.gif .