Small popping noises coming from exhaust when engine braking

[TorqueEffect]

Basically ever since the B6 was installed and the exhaust been welded up, when I engine brake, or coast down a hill in gear, I will here small random popping noises coming from the exhaust. Like mini-backfires. What's the reason for this? I can only assume either unburnt fuel from running rich, or the timing.

[bravekozak]

Another guy did all sorts of tests...


"so today while i was driving the car, the popping is still occuring. i started thinking if it is something else causing the popping.

Can exhaust collector gaskets going bad leak out exhaust pressure and at certain load ranges of the engine cause the back pressure to pop out of the exhaust instead of just exiting through the tail pipe.

on heavy acceleration, i dont get any popping occuring, but if i littly accelerate, the popping occurs.

after i got home i checked the gaskets at the collector and they do leak a bit of exhaust.

any comments. "

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In a word , Yes . Fix the exhaust leaks . They will make a popping sound . Irritating , isn't it ?

[koRnhead]

Its called overrun. Its normal. enjoy it.

[zoom zoom]

you don't have a cat, if you had a cat it would mask all those noises.

[rmoltis]

i had the same issue at one point even though i had my catalytic converter and everything still installed.
It only happened at idle and im not sure what caused it or even what fixed it.
the only things changed since it went away were.
changes in fp,
changes in timing,
changle in idle speeds,
went from non heated o2 sensor to a heated type.
pod intake filter installed.


im not saying these things will fix your issue.
just letting you know the items that have been altered since that point.


but by the sound of it it seems you may have some extra fuel heading into your exhaust stream.... maybe

[TorqueEffect]

I should have known it was because of the lack of a cat.

[wrestler3025]

Did you ever figure this out? It could be caused by a small exhaust leak upstream of the mufflers. When they welded your exhaust, maybe they didn't get a 100% seal. My mustang had the same issue, and it was just a pinhole leak. I rewelded it, and it stopped.