Hey everyone


I went home from school the other day for a few hours, just to finish up my headlight rebuild, which I finally completed and now have fully functioning headlights again.

So, upon completing the rebuild, I started the bird up and let her warm up for a while, and then, just because I love to hear that L98, I gave her a few nice revs. I noticed that when I rev it up, if I rev it up a good bit and then let off the gas completely, the exhaust will backfire and pop and stuff. It will happen every time, and it has happened consistently over the winter, that I've noticed. Only through the exhaust from what I can tell, I don't think its ever backfired through the intake. At least, I certainly hope not!!!!

Now, I personally think that it sounds kind of cool lol, but I know from quick internet browsing that it's possible that it could mean that the engine has a lean condition and needs to be retuned? I saw that on an LS1 forum, but I have an L98, and I was under the impression that the car's computer was supposed to do all of that stuff automatically lol.

So, my question is, is this most likely due to my needing a new exhaust? I do have an exhaust clamp holding one section together, so it's possible that there are air leaks and I'm told that this could cause backfiring.

On another note, I also still notice a slight hesitation when I step on the gas, if it means anything. Not normal, gradual acceleration. I mean when I really step on the gas to accelerate hard, or, if the car is parked, just to give the car a good rev. It's not like instant throttle response, it takes a second or two for the engine to "catch up" to my foot stomping the pedal, if that makes sense. It's hard to explain. The car runs fine when I drive, drives perfectly normally, no stumbling or anything, it just has this hesitation when I step on the gas hard, and backfires when I let off the gas after stepping on the gas hard lol. Not sure if the 2 are related, but who knows!


Thanks!!

DanJz

 

bump

 

anybody?

 

take a timing light to it. from the sounds of it, its off.

 

i would also check tps voltage

 

thanks guys, I'll have to give those a shot

 

So is it a like a pop pop pop pop when you let off the throttle mine did that when the cat converters wear blown out and mine probably damaged the inside of my muffler.
I changed the cats and a lot of that popping went away but not all of it take a temp gun to your cats if you have them they should be hotter on the output side then the input side.

 

Yeah it actually sounds just like that.

Now that you mention it, I do believe that the cats on my car are completely shot lol. I used to be able to hear the insides of them rattling around when I was stopped and idling, but now I don't hear anything, so I think I probably blew them out. I plan on replacing them when I get my new exhaust, which might be this summer. I'm thinking a cat-back exhaust system, 2 new cats, and a new y-pipe, and possibly some emissions-legal headers, but we'll see

 

Dan,

Before you go throwing a lot of money at a new exhaust system, I would make sure you have eliminated the more simple and less expensive possibilities. Have you hooked a code scanner/data logger to the car? Maybe try replacing the O2 sensors?

That car had to pass emissions here when I had it, and it passed by a wide margin. That suggests to me that the cats are not plugged or broken, unless they have become so in the time that you have owned the car.

Good luck!

 

Hey Dave!

I actually haven't had a chance to plug the car in and get any codes, but I'll definitely have to give that a shot as soon as I can