new resonator, new hissing exhaust sound

[pgibbzz]

I just had my resonator replaced at a local shop, and on the way home when i accelerate it makes a loud hissing noise like air being pushed out of a leak. the noise does not happen when parked and i rev it up. i plan on taking it back to the shop because the noise did not happen with my old resonator. but just wanted to get some of your thoughts on this cause maybe it could be something more than a leak. im going to try and post a video of it today.

 

[Blckshdw]

I just had my resonator replaced at a local shop, and on the way home when i accelerate it makes a loud hissing noise like air being pushed out of a leak. the noise does not happen when parked and i rev it up. i plan on taking it back to the shop because the noise did not happen with my old resonator. but just wanted to get some of your thoughts on this cause maybe it could be something more than a leak. im going to try and post a video of it today.

This is your truck's way of saying...

"I don't want no stupid can back there!"



If the noise isn't engine RPM related, but road speed related, I'm not really sure what that would be. First thought is that something is catching the air as it travels by, but it would need to be pretty large to cause enough wind noise to be heard in the cabin from underneath the truck. Hopefully it's something simple and the shop can fix it quickly for you.

 

[dmanns67]

Traded the resonator rattle for hissing huh.

That is strange you cannot replicate the sound by reving the engine in park. Have you tried to hold your rpms steady versus reving the engine to replicate the hissing sound?

 

[pgibbzz]

Took it back to the shop, he said its the aftermarket resonator making the noise, and the sound might go away in a couple of days. not entirely happy about it. its one of those bullet resonators. the sound happens when i really hit the gas quickly, if im just slowly climbing up to 3000rpms it sounds normal.

the size comparison between the stock resonator and the aftermarket is a HUGE difference. the stock is 3 times bigger.

 

[Pittdawg]

Took it back to the shop, he said its the aftermarket resonator making the noise, and the sound might go away in a couple of days. not entirely happy about it. its one of those bullet resonators. the sound happens when i really hit the gas quickly, if im just slowly climbing up to 3000rpms it sounds normal.

I call B.S. I have a bullet style resonator too, no hissing at all. It slightly dampened the exhaust sound but mostly just mellowed/deepened the exhaust tone.

 

[pgibbzz]

I call B.S. I have a bullet style resonator too, no hissing at all. It slightly dampened the exhaust sound but mostly just mellowed/deepened the exhaust tone.

im going to wait a few days see if it maybe goes away, i also am going to try and make a video of the noise (since it only happens while driving) maybe one of you can recognize the issue. i went to a shop recommended by a friend to save a few lousy bucks, and just my luck something like this happens. i shoulda just went with a straight pipe, but i was worried because when i cut my resonator off it sounded like a 1989 toyota corrolla (with no pipe from the hanger back).

 

[Showtyme]

Well I'm glad for my own personal reasons that someone else finally has the same problem as me. I have a completely stock exhaust system but have been dealing with this same problem for over 2 years now. I originally posted a thread on the OS but gave up quickly because the responses were all about wind noise. I dont believe the sound is wind noise since i can run 90 mph down the interstate and never here it. Only under wot above 3000 rpms. Since I rarely do this and have never seen any disadvantages in performance or fuel economy I've blown off the problem. WTF!!!??? The only reason I still have the stupid ass trash can is cuz the wife won't let me cut it off. Turns out this may be the source of the problem the whole time!? I'm about to go hack it off right now. Sorry for the rant but I've been waiting a long time for this day.

 

[Showtyme]

My original thought (since I'm an EXT) was the rear heat/air system having a vacuum leak. I see you are SWB so that rules that out. Does anyone know if there are any vacuum lines in the rear? Gas tank is the only place I would think.

 

[dmanns67]

I'm about to go hack it off right now.

Do it! The wife did not see me cut it off so she had no clue. She cannot hear a difference either.

Personally, I only heard a slight change in exhaust frequency once I added the straight pipe and tip.

 

[Showtyme]

Do it! The wife did not see me cut it off so she had no clue. She cannot hear a difference either.

Personally, I only heard a slight change in exhaust frequency once I added the straight pipe and tip.

This is definitely happening sometime in the near future. I gotta know if this is where the strange hissing sound is coming from.

 

[pgibbzz]

My original thought (since I'm an EXT) was the rear heat/air system having a vacuum leak. I see you are SWB so that rules that out. Does anyone know if there are any vacuum lines in the rear? Gas tank is the only place I would think.

i actually DO have a vacuum leak somewhere (before exhasut problems). ive had it ever since i cleaned my throttle body. the check engine light goes on when i start it up multiple times in a row, then turns off after a day or so. i hear a "sucking air" sound when i hit the gas while stopped and it bogs down like its going to stall, and idling is not bad but i can feel it going up and down (only after i cleaned my TB) even though rpms seem to stay steady. i know its the resonator though, i just had installed and i immediately noticed the problem. if this bothers me too much ill just cut it off again and eat the $80 :banghead:

 

[Showtyme]

i actually DO have a vacuum leak somewhere (before exhasut problems). ive had it ever since i cleaned my throttle body. the check engine light goes on when i start it up multiple times in a row, then turns off after a day or so. i hear a "sucking air" sound when i hit the gas while stopped and it bogs down like its going to stall, and idling is not bad but i can feel it going up and down (only after i cleaned my TB) even though rpms seem to stay steady. i know its the resonator though, i just had installed and i immediately noticed the problem. if this bothers me too much ill just cut it off again and eat the $80 :banghead:

Did you disconnect the battery to reset the pcm when you cleaned the tb? I had to do this twice the last time I cleaned mine. First time may not have been long enough. As for the vacuum leak, have you checked the hose on the bottom of the intake resonator that connects to the valve cover? Please keep me posted on what happens with the exhaust resonator. I doubt the sound is gonna go away all on it's own.

 

[pgibbzz]

Did you disconnect the battery to reset the pcm when you cleaned the tb? I had to do this twice the last time I cleaned mine. First time may not have been long enough. As for the vacuum leak, have you checked the hose on the bottom of the intake resonator that connects to the valve cover? Please keep me posted on what happens with the exhaust resonator. I doubt the sound is gonna go away all on it's own.

i did not disconnect the battery, just the pcm, ill have to check that hose. and i plan on posting a video eventually on the exhaust, just need another set of hands to help with the camera work.

 

[pgibbzz]

So i have decided to hack the trash can off AGAIN. I cant stand to listen to it anymore, ill end up taking a $79.00 loss, and i dont feel like going back up to this ghetto shop for the 3rd time. I was wondering what size pipe can i fit into the pipe that is before the hanger. I probably just use a clamp and see how it sounds. The reason i decided to buy another resonator was because i didnt like the sound, then i read that its less noisy if you have a long straight pipe. So im going to try that... Could this hissing noise have anything thing to do with other exhaust components?

 

[dmanns67]

I was wondering what size pipe can i fit into the pipe that is before the hangerm

Straight pipe 18" long, 2.5" ID. Pick up a 2.5" exhaust clamp.

 

[pgibbzz]

Straight pipe 18" long, 2.5" ID. Pick up a 2.5" exhaust clamp.

thanks, i was finally able to buy something that i didnt have to go back to the parts store and exchange.

GOOD NEWS! I deleted the NEW resonator, added a 18", 2.5" pipe with clamp (with is all temporary until i can weld it on), and it sounds GREAT! That extra 18" from the hanger makes it alot quieter, even though i think i need a few more inches (thats what she said ), i plan on bending the exhaust so it comes out behind the passenger tire. Now for whatever reason after i cut the new one off, vibration while idling at a red light has stopped. I think the resonator that they sold me was a can of shit and did not fit my vehicle whatsoever. Yes i lost $80.00, and most people would take there car back and do whatever to get there way, i just didnt want to scratch and pull over it and have some mechanic make more shit up why its not working properly.

 

[Blckshdw]

thanks, i was finally able to buy something that i didnt have to go back to the parts store and exchange.

GOOD NEWS! I deleted the NEW resonator, added a 18", 2.5" pipe with clamp (with is all temporary until i can weld it on), and it sounds GREAT! That extra 18" from the hanger makes it alot quieter, even though i think i need a few more inches (thats what she said ), i plan on bending the exhaust so it comes out behind the passenger tire.

Glad to hear things are working out better for you. I'm sure you'll be cheesin from ear to ear once you get this all buttoned up and can sit back and enjoy it.

Now for whatever reason after i cut the new one off, vibration while idling at a red light has stopped. I think the resonator that they sold me was a can of shit and did not fit my vehicle whatsoever...

Like I was saying...

This is your truck's way of saying...
"I don't want no stupid can back there!"

 

[Pittdawg]

I call B.S. I have a bullet style resonator too, no hissing at all. It slightly dampened the exhaust sound but mostly just mellowed/deepened the exhaust tone.

Like I was saying...they was bullshi$#ing you!

 

[Showtyme]

I had the chance to hack mine off today. No extension pipe or anything yet. Ill get to it when i can. So mine is just plain cut off now and dumping under the truck. It has alot more sound now but not annoying. I really like it. The main reason i did this was to find out if this was the culprit for the hissing sound at wot. Took it out for a nice long test drive and stomped it to 6 grand several times and never heard the hissing sound. Once i got my resonator off i could hear all kinds of shit in it and rusty pieces of metal fell out of it. This was probably the cause for my rattle and hissing sound. Just wanted to share my experience.

 

[Showtyme]

thanks, i was finally able to buy something that i didnt have to go back to the parts store and exchange.

GOOD NEWS! I deleted the NEW resonator, added a 18", 2.5" pipe with clamp (with is all temporary until i can weld it on), and it sounds GREAT! That extra 18" from the hanger makes it alot quieter, even though i think i need a few more inches (thats what she said ), i plan on bending the exhaust so it comes out behind the passenger tire. Now for whatever reason after i cut the new one off, vibration while idling at a red light has stopped. I think the resonator that they sold me was a can of shit and did not fit my vehicle whatsoever. Yes i lost $80.00, and most people would take there car back and do whatever to get there way, i just didnt want to scratch and pull over it and have some mechanic make more shit up why its not working properly.

Did your hissing sound go away with the resonator cut off?