Very loud umm..not exactly popping when I let off Gas

[sccobra04]

Every day I drive my car I notice that when I let off the gas anywhere above 2300+ rpms I get a lot of what I guess you could call "blurb blurb blurb blurb" almost like very small backfires but not a backfire cause it isn't that loud. I am used to a smooth deceleration sound in my other vehicles so this just seems really weird to me.

It can get really annoying since most of the time I am above 2300 rpms especially when accelerating, and if I let off even in 5th gear on the highway around 65 mph you can hear the exhaust blurbing loudly as you decelerate almost as if it is coughing. Anyone know what might be the culprit here? Think I should just remove my cat? Could it be the wrong type of muffler on the vehicle(it was on it when I got it)? It just sounds so awful when I let out of the gas and have to hear it sound like it is choking on the the backpressure...

ANY help would be much appreciated
thanks,
Derrick

[jory]

it might have an exhaust leak. if it's the stock size replace it with something less restrictive.

[RGHoskins]

it's normal....I'm guessing it has a low restriction muffler? you just can't hear it with the stock exhaust. hell, i like it....lol. it's caused by unburned fuel combusting.

[william]

My car starting doing this a while back. I traced the problem to my loose distributor hold down. Over many miles, the distributor was retarding itself (rotating) and the further it retarded, the worse the popping got. When I reset the timing back to where it was supposed to be, it disappeared almost completely. I run open exhaust, no muffler or cat.

[GLHNSLHT2]

assuming the timing is right it's normal. The computer doesn't cut fuel ompletely on decel so you get small backfires out the exhaust.

[Turbo-Baron]

I have a 2.5"magnaflow on my baron it does the same thing. I Love It!

[Billz]

Make sure you aren't running pretty rich. I have a custom cal, and was way too rich. Back the fuel pressure off until I wasn't so rich, the ''blurbing'' calmed down a lot. It didn't go away completely because I do have my ignition timing retarded to 8 degrees because of running 20 PSI on pump 92 octane with a swirl head. I ran a G headed 2.2 before with full timing an 22 PSI, but I wouldn't do it with a swirl head on stock T1 pistons!
BTW I'm running 3'' exhaust, no cat, and a dynomax ultraflow muffler.

[iTurbo]

If your speed/distance sensor is not working, the backfire and popping on decel will be a LOT worse.

[TurboBuggy]

If the distributer is turned to far out of time it will make this worse but its normal to have some popping, when I switched to a mopar performance cal it went away completely. Actually when I leaned the fuel out down low it came back but if I made it richer it went away

[phantomrt]

Back when I got my built 2.5 turbo going, I was just running 2.5" exhaust all the way out the back. No catalytic converter, and no muffler. It would sound like a .22 caliber rifle sometimes when I let off the gas. I did not run it like that very long. A thousand miles at the most. I installed a dynomax straight-through muffler, and there is no more .22 caliber effect.

I'd look at ignition timing and do a compression check for curiosity's sake.

[sccobra04]

I wanna thank everyone for their quick responses.. I am going to recheck my timing again. Also, how would I time for 14' btc? Can I do this by looking at the marks on the transmission housing? The marks read : 0 4 8 12...right now when my #1 cylinder is at tdc the mark in the "window" of the trans housing is pointing on "0" Should it be between 0 and 4 or what to advance the timing?

thanks,
Derrick

[lotashelbys]

EVERYONE of my 8valve cars that had "other than stock" exhaust did the whole "pop,pop,pop" on decel when you were totally off the throttle. I noticed it even more on a 2.5. I think thats how they sound and you will just have to get used to it

P.S. If you were to ever go with +40s it should cure it. At least it did on everyone of mine

[william]

Timing for 14*? I am guessing you must be running a G head/swirl pistons looking for that kind of advance? I use a timing light with the adjustable wheel on it that allows you to check full advance. It retards the light up to 30* or something. If you set the dial to 14, just line up your marks with the zero on the trans. If you are running a G head with swirl pistons, you may have to go for even more advance unless your cal is setup for the g head. I was running as much as 16*, and found that the car ran very poorly at 12-13*.