i know i have an exhaust leak, and its right where the 4 tubes on the header collect into 1.....we tryed to patch it up, but its been welded about 40 times, and we even tryed some JB weld...we got the hole down to a pretty smalll size, but the car still pops really loud, mostly when its cold...i've heard exhaust leaks on other cars, and i'm pretty sure it shouldn't pop....it mostly does the popping when its cold, or when i rev it up to like 5 grand, and totoally release the throttle, and when the rpm's decend, it does a series of pops, or 1 really loud pop...like it sounds like a basketball exploding...ITS REALLY LOUD!!! my question is, is the popping from the ehxuaast leak, or is it from the engine not running right? i've heard some suggestions from people, and the most reasonable one is, since my car is runnin a bit rich, that some fuel is getting into my header, then igniting, causing a huge pop...cause when it pops, you can see flames riht down there where the hole in the header is...i need some major help, cause this problem is really startin to stress me out, its hard to show off your exhaust when it pops, or starts poppin when you shift gears...

 

Yes, and its called afterfire. Basically when you let off the throttle you're running really rich, and the extra fuel gets dumped out the exhaust. This fuel combining with the extreme high temps of the pipes with the air provided by the exhaust leak causes combustion in the exhaust.

And for some reason large single exhaust systems seem to be the worst - much like most F-body systems.

Either fix the exhaust leak or have the PROM custom tuned to cut off fuel upon deceleration conditions, like many OBD-II vehicles.

 

i think its runnin rich all the time, not just during deceleration...how can this be adjusted? can a local mechanic go into the computer and change this without having a rediculous bill? I'm goiing to get a new cap, rotor, plugs, and wires this weekend, so that might eliminate a little bit by having a more complete burn....could the bad MAP sensor be causing this too by sending the computer false information?

 

Again, not MAP, MAF. And yes, that could cause it. Besides poor ignition, other cmmon possible causes include too high fuel pressure or a Throttle Position Sensor out of adjustment. There are a few less likely issues, but check the obvious first.

I still think the problem is mostly related to the exhaust leak. My #8 primary rear bolt, the back one on the passenger side, has a habit of loosening itself. Even before I notice the tick, tick, tick of the leak, I hear the afterfire. A quick tightening eliminates the leak, and rids the exhaust of the popping.

 

well i just got done replacin the header gaskets, so its not leakin out of there anymore, but i'll work on it all weekend, and hopefully i can get it solved by early next week....we can't really fix the exhaust leak anymore cause its been welded about 20 times already, and its kinda hard to get in there with a welder again.....so my dad said we were just gonna leave it all summer, than totally redo the ehxuast this winter with new headers, custom y pipe, and 3 1/2 inch pipe all the way back....so i'm gonna try to eliminate it as much as possible till thsi winter, hopefully i can wait that long...