Engine exhaust backfire

[bobbystone]

Just noticed some random popping in my exhaust on the port 454. Can you guys give me some ideas n where to start diagnosing the culprit? Spark plugs?


Is this potentially damaging to the engine?

[evansjw44]

Popping in the exhaust? That might be excess unburned fuel being lit off in the exhaust which points to ignition problems like plugs, wire etc. The alternative is a cylinder firing with the exhaust valve not fully fully closed or leaking. A compression or leak-down test might find that, especially a leak down test.

[tkhersom]

Leakdown test is a great way to find problems.

"Technical note" backfire is though the carb, while fire in the exhaust is actually "afterfire". Few people use this term or even know it exists.

Hope this does not seem like I am being too fussy on terms just thought it would make a good conversation starter.

[bobbystone]

Interesting! I never heard the term "after fire" before. Makes perfect sense since a "backfire" is firing BACK through the carb..

Thanks!