Exhaust Popping

Sorry to keep submitting so many new threads, but I am new jeep owner and yall are very informative and helpful. I would like to try to do some of the work myself on my new CJ5, so I am researching these things everyday. I need to focus on one problem at a time, so I guess I am going to have to make a list and prioritize what needs to be done first.

Anyways, my latest discovery on my new jeep is a loud popping sound from the driver's side exhaust. It is a 304 with headers and side pipes and whenever I rev it up and let off (or let off coasting down the road) the exhaust pops (sometimes worse than others). To me, it sounds like it may be getting air somewhere. Has anyone experienced this and can at least help me with where to start, or could there be bigger problems causing this pop?

 

normal backfiring. My 304 does the same thing.

 

could be timing to far adv, leak at carb to intake ,or it's just been hanging out with a UPS truck when your not around..........

 

Popping is caused by unburned fuel in the exhaust. An exhaust leak would make it worse, I presume, by adding O2 to the exhaust gases.

If this Jeep has an aftermarket carb and headers, I would not be surprised that it pops some. Typically aftermarket carbs are set up much richer than OEM carbs, and the loss of exhaust back-pressure with a free-flowing exhaust should raise the amount of air in the exhaust.

Too far advanced or an intake leak would make the exhaust leaner. I don't see how this could cause popping, unless the condition were so bad that it makes the cylinder misfire. Following a misfire, the air-fuel charge would be pushed out the exhaust, and that could cause a backfire.

If it were mine, I'd look at things like air-fuel mixture, oil pressure and compression. A compression check combined with oil pressure readings will give you a good idea of the overall condition of the motor. You can check the mixture by looking at the spark plugs. If you want to add some spiffy gauges, an O2 sensor in each downpipe will give you a real-time reading of the air-to-fuel ratio.

hth!

 

I've been thinking about this too. My 304 with headers and a Edelbrock(Rodchester) 4bbl pops, but only out the passenger side. I haven't pulled the plugs to look at the color but I wonder if the mixture is adjustable from left to right bank of cyls? My thoughts were is one bank running richer than the other,

 

Idle mixture could be different, left to right. There's a plenum in the manifold under the carb that should minimize any unbalance though. Exhaust leaks are also possible. Headers are typically leaky.