I have an N1 and an HKS downpipe and I seem to be getting a lot of backfiring. I get most of the backfiring at low RPM like 2k or 1.5k...and I get the strong ones sometimes at high RPM when I quick shift gears. Should it be running this rich?

 

When I went from totally stock exhaust setup, to a full straight exhaust I also noticed a lot more backfiring. I dont get much in low RPM's but I get some loud ones up high. Is this normal? Sorry I couldnt help. Im thinking maybe I am running a little to rich.

 

Have you had the catback and downpipe on for a while and the backfiring has gotten worse, or are you just now noticing the backfiring after the install of those items?

I notice that my car will backfire quite a bit until it warms up. After that, it usually only backfires when decelerating.

Also, when was the last time you changed your spark plugs?

 

I just installed my whole exhaust setup I havent even really drove it Im still installing stuff. You think the Spark plugs could be doing it?

Mike

 

Spark Plugs were changed about 5k miles ago. The Backfiring happens on deceleration on mine too, the only time it does it in acceleration is at high RPM when I shift.

Also I had a bit of backfiring with the stock exhaust, but not much. It's noticably more with the exhaust (although maybe I could just hear it better)

Could it be a sign of a bad o2 sensor?

 

Sounds normal.

You'll get quite a bit more backfiring after removing the pre-cat.

 

The backfiring is normal. Not all of the exhaust gases are not getting combusted due to the lack the precat. My car does the same thing and I get alot of carbon buildup in the tailpipe. I only backfire under deceleration.

Imagine if you had a midpipe---->you would be shooting fireballs!

 

I have a MP and I shoot flames too but also backfires quite a bit. But it sounds like this is normal, thats what I thought. I still think I could take out a little fuel though.

 

post some fireball video clips