98-LS1

iTrader: (4)

I have a 2001 Z-28 with the SLP loudmouth exhaust, stock manifolds, Y-pipe and Converters. Ever since I installed this exhaust system the car has been popping really loud through the exhaust whenever I push in the clutch and let off the gas to change gears. It sounds almost like a backfire because it's loud as hell. What could cause it to do this? It only does it when it's cold, once the cars warmed up it doesn't pop at all. I have never heard another LS1 car do this. Now my rear O2's are disconnected and my SES light is on for those codes only but that shouldn't have anything to do with it would it?? Any idea's would be appreciated! Thanks

Blackhawk777

It could. No rear 02 sensors could possibly be making it run rich.

wssix99

iTrader: (5)

My stock car has done this from the factory, right at start up - but to a very small degree and it only lasts for the first minute or two. Having your O2 sensors off may make it harder for the PCM to get the right mix when the engine is cold, and could exaggerate this effect.

If you take it easy on the gas until you are up to temperature, it should help.

98-LS1

iTrader: (4)

I don't beat on the car when it's cold but I live on a fairly steep hill so I have to give it a little more than normal. I've been trying to make it a habit to warm the car up before pulling out. My 98 never did this even with the rear 02's disconnected before and after the tune.

9000th01ss

iTrader: (10)

It's the AIR system pumping air into the exhaust I would guess. It's does it for 70 seconds after startup. Or about 1/4 mile of driving.

I turned my air pump on manually and drove around the block before it removed it. It was doing the same thing, loud popping on deceleration.

m6speed

iTrader: (11)

your car is cold and is running rich, when you let off all that fuel is causing the popping noise, you could fix it with a tune....adding a louder exhaust just made it more apparent.

not rocket science

samson_420

iTrader: (1)

Mine does the same thing. It is just more noticeable after I got my exhaust.


I think it's kind of cool. It just makes it sound more burly.

ae13291

iTrader: (8)

its normal the o2's are in open loop mode it runs rich till normal engine temps to be safe. i kinda like back firing on mine, it makes it sound mean

Dskeet6

iTrader: (20)

its the air system...... when unspent gas gets into the catalytic converters it can be ignited when it gets fresh air from the air pump......??? mine did this before i removed the air pump, not after

LSex

iTrader: (1)

For like the first 3 minutes maybe even less my car does the same thing when I let off the gas. When the car didn't have cats it did it and now it does it still does it, just not as loud My dad has a 01 bone stock besides a few slp things, it has like 15k on it he says it does the same thing. If continues after any more than like 5 minutes id be concerned but i never get more than maybe 3-4 pops out of mine for maybe like the first 2 minutes sounds like you are experiencing the same thing....

SLICK_LS1

iTrader: (10)

I just finshed having that problem man. I did all the same things everybody did. But then i checked my spark plug wires and one of them was not fitting right. Making sparks and that noise. Im guessing it can be that because of that spark plug wire which not all the fuel was being burned which will cause that pop to come up.