Six Pack popping back through exhaust at idle

[Ghoste]

Suggestions?

[rt green]

first, ck firing order. look over  ignition system completely. second ck compression. I say this not knowing the history on this.   does it run rich?  power valve comes to mind.

[Ghoste]

Ran perfect to now and completely stock.

[rt green]

does it pop with rpm also?

[Ghoste]

Nope, only under 1000.

[rt green]

when pulling plugs for compression test, check for carbon deposits on plugs. could be carbon deposits on piston tops from todays wonderful fuel. if these stay burning they could set off the fuel charge at the wrong time. if you find this to be the case, try some BK 44k fuel system cleaner. this has proven to be very good stuff.    

[A383Wing]

broken valve spring?

[firefighter3931]

It could be several things ;

-low voltage to ignition system
-timing retarded with unburnt fuel ignitiong in the exhaust
-insufficient fuel supply at low engine speed producing a lean pop
-cross fire in the distributor



Ron

[Ghoste]

Turned out to be pcv.

[rt green]

well there we have it then