Thread: N54 Backfiring?
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      07-11-2011, 08:10 PM   #7
IGoFast1589's Avatar

Drives: 08 135i
Join Date: Nov 2010
Location: NY

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Originally Posted by Dackelone View Post
Originally Posted by 330iSB View Post
are you sure its backfiring and not just the "gurgling and popping"? I have full catless and I get lots of gurgling and popping but they only time i ever get a hint of backfire is when i am wot at low rpm and then shift gears before 3500 or so

Heck! My N54 exhaust is all stock and it also gurgling and pops! I love it though. I think plenty of V-Max runs on the Autobahn helped in reaming out my exhaust pipes. lol I know lots of people are surprised when I tell them my exhaust is all stock!

OP - I bet you re-used your old exhaust gaskets. Most backfiring or severe popping comes from an exhaust leak upstream. A true back fire would mean your engine is running super lean. I bet its your old (leaking) exhaust gaskets.

Have a helper take some rags and hold them against the exhaust tips while the engine is running. Then YOU can go under the car (while its jacked up and on jack stands!!) and check for leaks. I bets its those exhaust gaskets at the downpipe/main cats to mid pipe flange. They take an awlfull amount of heat and are prone to be "one time" gaskets. It could also be further back at the muffler too.

Good Luck,
Backfires come from a rich mixture, Dackel. My old STi would make really loud backfires between shifts as the AFR's would dip towards the richer side of the scale for it's cooling benefits.