exhaust noise

[usaf2006]

While driving around town, I can hear my exhaust echoing off of objects, and it seems when I am just cruising I have an exhaust leak, but when I use any throttle it goes away. I can't pinpoint where it is, but I don't see any holes except in the muffler and resonators, each one has a tiny hole on the back bottom in assuming for water escape. Anyone else experience this? Or have an idea why it would seem my leak would go away?

 

[Harley Harrold]

While driving around town, I can hear my exhaust echoing off of objects, and it seems when I am just cruising I have an exhaust leak, but when I use any throttle it goes away. I can't pinpoint where it is, but I don't see any holes except in the muffler and resonators, each one has a tiny hole on the back bottom in assuming for water escape. Anyone else experience this? Or have an idea why it would seem my leak would go away?

Check your exhaust manifold bolts/studs for broken off heads, this happens a lot, and if you find any the manifold will have to come off. The manifold would need to be checked for warpage, and resurfaced or replaced. Be sure to use new bolts/studs and the OEM gasket. Also be sure to properly TORQUE the bolts/studs to factory specs.

 

[xb1230]

I had a very similar issue when I bought mine last year and it ended up being the flange connecting the exhaust to the manifolds. A good muffler shop just cut the top of the pipe, welded a new flange on a new length of pipe and I was off to have a quiet truck again.

But the Manifold leak is also very likely.

 

[usaf2006]

Will do guys. Thanks! I'll report back with my findings.

 

[justin13703]

If you can't find anything leading to a leak, keep in mind that your truck has the MDS system that will run on 4 cylinders when cruising that makes a very different sound than when it is running on all 8. This may be what you are hearing

 

[usaf2006]

MDS should only activate at speeds of 35 and above correct? If so, its probably not that because when I'm coming into my subdivision I'm only doing 20 at best which the sound is present. However, there's this hill I have to go up do my truck down shifts when I give it some gas and the sound goes away.

On a side note regarding mds, does anyone else have an issue with it sound 35 mph? It seems when I hit the activation threshold, if I let off the gas, its like my truck does know what's going on cylinder wise. As soon as I let go of the gas at 35 my truck sort of shudders . Nothing in suspension, you can feel it from the motor. It'll constantly do it if you feather the gas around that point. I try to stay around 38mph but sometimes you get caught behind those everyday-is-a-sunday drivers. Thoughts?

 

[caps]

If you think it's MDS put it in tow mode while it's making the sound. Tow mode won't let MDS engage.


Sent from my iPhone using Tapatalk

 

[usaf2006]

Nice I'll have to try that. If mds is screwing up, what can be done about that besides disabling it via a tuner?

 

[usaf2006]

Tow mode took care of it. What do you think I'd need to do to fix the issue? Also, is it okay to roll in tow mode for a while? Or would that do harm.

 

[xb1230]

It will only harm your wallet as your MPG will go through the roof.

But otherwise I don,t think it would break anything unless you have a lot of highway driving to do, at which point it could get your transmission to heat up.

However I would still keep looking for the source of the noise if it changed from what it was before, and get things fixed.

My 2 cents.

 

[usaf2006]

No highway driving for me on my work commute. Well see how my mpg acts. Once the weather warms up I'll get some better investigating done. What tuners can disable mds, and also have an economy tune, nothing crazy for performance.

 

[TXLimited]

I have a Diablo InTune and just disabled my MDS last week because I was sick of the 4cyl exhaust noise (running an 18" mufflex made the sound more apparent). As far as mpg, mine have actually gone up since turning it off, and there is consistent power throughout all driving speeds, no more surging between 4cyl and 8.