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After 2nd muffler blowout....Eureka !

Guest fmbjogger

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Guest fmbjogger

My '74 DeVille was backfiring after punching the pedal. After first muffler blowout, rebuilt carb, replaced vacum lines and replaced divorced choke pulloff.....BANG....second blown muffler. Now I'm pissed.

Checked with an old carb guy and he suggested I check pollution pump setup. Pulled the line and....no backfire. bypassed the system and all is right in Cadillac world.

Can anyone explain what's up with system ? Thanks !

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How about "diverter valve"?

While you're under there, be sure to check the two check valves, one on each of the distribution manifolds. When they get weak (there's a rubber diaphram in the valve), they let hot exhaust gases get upstream toward the diverter valve and air pump. "Things melt" from that kind of heat where it shouldn't be!

Just some thoughts . . .


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