Author Topic: Popping sounds from carb maybe?  (Read 3289 times)

Offline 1979ChevyMorgan

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Popping sounds from carb maybe?
« on: August 14, 2014, 10:36:55 PM »
So im driving down the interstate and my truck start to makes this popping noise and I loose all power. Ive got a 454 big block so there should be lots of power. Anyways, i put her back home and she makes this popping sound when i accelerate and/or rev the engine in nuetral. I fiddled with the timing and no luck there. Havent taken a look at the plugs and wires yet cause it got dark on me. Weird thing was when i would down shift to 2nd, it would not make the popping noise only when i push on the gas. idel is a bit rough too.

Also she is VERY hot too, new thermostat and plenty of fluid so im not sure why she still runs so hot. I will open the hood and its like a heat wave coming out. Well id appriciate any help you guys can give me.

1976 Chevy with 1979 454 with 750 Edelbrock carb.
« Last Edit: August 15, 2014, 08:17:09 AM by bd »

Offline bake74

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Re: Popping sounds from carb maybe?
« Reply #1 on: August 14, 2014, 11:36:22 PM »
     First question that needs to be answered, is it popping up through the carb, or from the exhaust ?  Makes a difference.
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Offline emod20

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Re: Popping sounds from carb maybe?
« Reply #2 on: August 15, 2014, 12:07:50 AM »
could be many things but one possible one is when an exhaust valve stops opening it will cause a rapid popping or backfire usually just when you crack the throttle. cause by one of the following worn cam lobe . pushrod broke or bent. rocker arm loose or broke.  other causes lean condition such as accell pump. fuel delivery problem ....just some ideas

Online Captkaos

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Re: Popping sounds from carb maybe?
« Reply #3 on: August 17, 2014, 12:32:28 PM »
By very hot have you verified the temperature?
as said it could be a number of things.  By chance did you fill up prior to this happening?

Offline 1979ChevyMorgan

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Re: Popping sounds from carb maybe?
« Reply #4 on: August 18, 2014, 04:56:08 PM »
The popping noise is from the carb, and no I havent verified the temp but i know that it is way too hot. It has never been this hot. I did fill up prior to my road trip. Ill take a look at those valves see if theres anything unusual there. Thanks for the imput, ill let you guys know with more details when I figure it out.

Offline bobcooter

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Re: Popping sounds from carb maybe?
« Reply #5 on: August 21, 2014, 10:59:53 AM »
Popping trough carb could be a flat cam lobe. I had a big block with a flat lobe and you would only hear it popping at certain speeds. As for the heat, is your timing too far advanced?
'79 C-20, 350/400, 3:73 gears, 9 leafs and a headache rack
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Online Captkaos

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Re: Popping sounds from carb maybe?
« Reply #6 on: August 21, 2014, 08:00:47 PM »
If you filled up before the trip, and everything else is ok, I would suspect bad gas.  Do you buy there often?

Offline 1979ChevyMorgan

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Re: Popping sounds from carb maybe?
« Reply #7 on: August 21, 2014, 08:59:37 PM »
Well found the problem, not a good one either. Camshaft is rounded.

Offline emod20

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Re: Popping sounds from carb maybe?
« Reply #8 on: August 22, 2014, 09:18:32 AM »
exhaust lobe ?