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Engine pops or backfires

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rmcomprandy
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Engine pops or backfires Empty Engine pops or backfires

Post  capncruncher1965 August 26th 2021, 12:07 am

My engine is a 472 it's been running great for over a year with no problems at all it started to pop or backfire some times never done this before it does it when it's first cranked and sometimes after being driven and cut off for a few minutes. I dont know if it's fuel or electric cap and wires are about a month old plugs are the same as wires I changed fuel filters they looked fine carb is a 950 quick fuel no dripping boosters. Any suggestions?
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Post  Dave De August 26th 2021, 8:35 am

Is the explosion in the intake or in the exhaust?
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Post  rmcomprandy August 26th 2021, 10:14 am

capncruncher1965 wrote:My engine is a 472 it's been running great for over a year with no problems at all it started to pop or backfire some times never done this before it does it when it's first cranked and sometimes after being driven and cut off for a few minutes. I dont know if it's fuel or electric cap and wires are about a month old plugs are the same as wires I changed fuel filters they looked fine carb is a 950 quick fuel no dripping boosters. Any suggestions?

Usually, when something like that just begins happening, it is usually because something is restricting the exhaust flow out of the engine so, it exits the cylinder through the next time the intake valve opens.

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Post  capncruncher1965 August 26th 2021, 10:33 am

I would never thought about that I'll check it this weekend and let you know what I find. Thanks for replying
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Post  738drvr August 26th 2021, 10:35 am

Check for an exhaust leak at the headers. Mine did that. You can check by using a shop vac that blows instead of vacuums. Spray the headers down good with soapy water then stick the hose over your collector. The bubbles will show where the leak is located. Make sure you clean the vacuum real good and use a fresh filter before you start.

These will fix it if that is your problem.

https://www.scegaskets.com/product-category/ford/ford-big-block/bb-ford-exhaust/

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Post  capncruncher1965 August 26th 2021, 11:36 am

Exhaust best I can tell
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Post  Dave De August 26th 2021, 12:36 pm

Popping in the exhaust is from raw fuel being ignited in the headers or exhaust. Carburetion issues can lead to this especially when raw fuel is puddling on the plenum floor. This can also be caused by a vacuum leak. Also main circuit flow or dripping from the boosters when the primary circuit should only be in operation.

Does the popping condition happen when the engine is cold?
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Post  capncruncher1965 August 26th 2021, 12:47 pm

Yes when it's cold and if you drive it some and then cut it off for like 15 minutes or so it does it sometimes and it just does it sometimes it might be a couple of days and it runs fine then it does it
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Post  Dave De August 26th 2021, 12:54 pm

Raw fuel rarely ignites in a cold exhaust. Maybe you have a header leak as others suggested.
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Post  rmcomprandy August 28th 2021, 11:23 am

capncruncher1965 wrote:Yes when it's cold and if you drive it some and then cut it off for like 15 minutes or so it does it sometimes and it just does it sometimes it might be a couple of days and it runs fine then it does it

If the popping is not in the intake, a rich cruising fuel mixture and lean idle mixture will also do this.
There are a lot of different scenarios which will contribute to this happening.

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Post  capncruncher1965 September 1st 2021, 12:32 am

Guys finely figured my popping problem out it was my distributor cap and rotor button a buddy of mine told me to check that because I run a MSD digital 6 plus and he told me those digital boxes are hard on caps and rotor Buttons. He drag race's and all ways carries a spare cap and rotor button with him at the track so I put a new cap and rotor button on mine and it has not missed or backfired, pop nothing so far. I think that fixed it hope so anyway. Just wanted to thank you guys for taking the time to help out. This is the coolest Ford website ever Thanks again
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Post  capncruncher1965 September 1st 2021, 12:36 am

Engine pops or backfires Fb_img12Engine pops or backfires Fb_img12
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Post  Mark Miller September 1st 2021, 1:49 am

capncruncher1965 wrote:Engine pops or backfires Fb_img12Engine pops or backfires Fb_img12

Engine looks good any problems with those fuel fittings seeping fuel on your carb fuel lines?I have a Quick Fuel Setup like that for my Dominator Carb and a Fragola Setup for my old 4150 HP carb and both of them want to seep a little fuel!

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Post  norm September 1st 2021, 8:47 am

capncruncher1965 wrote:Guys finely figured my popping problem out it was my distributor cap and rotor button a buddy of mine told me to check that because I run a MSD digital 6

I wonder if it's because you use the small cap? I have ran that box for years with the big ford style cap and i believe i've only replaced the cap and rotor once, and that was I was chasing a miss that turned out to be the pick up so the old cap and rotor i keep as spares.
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Post  capncruncher1965 September 1st 2021, 9:33 am

I don't know if the small cap makes a difference or not my buddy also uses the small cap that might be the problem if it starts messing up again I'll try the big cap
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Post  Dave De September 6th 2021, 10:37 pm

Air cleaner is too small.
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Post  capncruncher1965 September 7th 2021, 1:27 am

I know but it's the only one that will fit in my hood scoop
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Post  tconnection September 27th 2021, 10:35 pm

...


Last edited by tconnection on September 27th 2021, 10:39 pm; edited 1 time in total (Reason for editing : out of date)

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Post  gt350hr September 28th 2021, 11:37 am

Just curious , who's headers are you using??

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Post  capncruncher1965 October 1st 2021, 2:23 am

They are critz that have been jet coated
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