That's BACKFIRE not AFTERFIRE! What ever the hell that means. LOL

 

Here you go. From the link provided for your reading enjoyment.

Popularly the term is used to describe a sharp report produced by almost any type of engine. However, among engine professionals, "afterfire" is the term used to describe ignition of fuel within the engine exhaust system and "backfire" is the term used to describe this same process taking place in the induction system, primarily in internal combustion engines. The separate terms are useful when troubleshooting running problems

 

That's great info! But, somehow I'm thinking that is NOT what the OP was talking about.

 

I'm damn near 75 years old and never heard it called after fire.
I've always heard the term back fire.
Of course I'm not a college educated professional.

 

That term must be used only by the Bill Gates' and Steve Jobs' of the automotive world. My dad is a retired mechanic and he never heard of that before.

 

i've never heard the term afterfire, but i like it. y'all don't be so pissy.

when i was a chap, the area where we lived was growing very fast, with new subdivisions going in everywhere. a county wide sewer system was under construction, but far from complete. so all the new subdivisions put in sewer lines down to the lowest point that would eventually tie in to the county system, but for several years, the county had a fleet of trucks that would pump out each low point. they were known as the **** wagons and they ran up and down the road day and night. the drivers had this game going to backfire (afterfire) the truck into the exhaust and scare the hell out of everybody. so it went like this - they'd see a target... another car, pedestrian, bicycle, guy cutting grass, etc and turn the ignition off and leave the transmission in gear. so the motor and fuel pump is still turning... then they'd pump the hell of the gas pedal over and over and over. you see where this is going... that'd fill the exhaust with raw gas. then they'd turn the ignition back on and KABLOOM. you could hear it for a mile or more and sometimes it would explode the muffler. it was funny for awhile but everyone started complaining and writing down the truck numbers and the county ended up firing about the half the fleet.

 

Well Gentlemen, I was calling this explosion in my exhaust system backfire when i was corrected my a mechanic saying that it is afterfire as it is taking place after original combustion in the exhaust where there is not suppose to be combustion. He also said most people call it backfire although it's not . On that note ....does anyone have any suggestions to fix this !??!

 

I've always called it afterfire -- "back" is back up through the throttle plates. I figure it's a case of regional dialect.

Afterfire is caused by excessive unburnt fuel in the exhaust stream. The classic dammit cause is a burnt exhaust valve. The "glad it's not the exhaust valve!" cause is something like a leaky injector, a weak spark, relatively obvious things like that. Since it's not happening under high vacuum conditions, chances are pretty good that ignition timing is not the culprit.

 

Ok Just a thought....When I installed My Pacesetter longtubes I deleted the EGR Valve by PLugging the end. I did not disconnect anything just plugged the end . Could this be causing the afterfire ? I'm going to unplug my brand new O2 sensor and go for a little drive and see maybe if it's a faulty sensor .

 

I could see it happening if your plug is leaking, sure. Try putting a pipe plug in the intake manifold so there's no chance of a leak there... you might get lucky.