Exhaust Noise at Idle

[electro992]

I replaced my leaky stock muffler with a new aftermarket piece (Walker), and now have the "exhaust boom" when the car is warm and idling in gear. The vibration shakes the whole car and goes away immediately with a small bit of gas. The old muffler had a weight attached to the back of it but the new one has no place to bolt one on.

Has anyone dealt with this before? Would one of those frame weights help, and if so, can I order it from Toyota? Thanks in advance.

 

[DJWUZJ]

Noise is one thing, but when it starts to shake the entire truck like you describe, thats when I start to worry.

Dumb questions...
- Was this a DIY or did you take it to a shop? If a shop, take it back and ask them to check their work.

- Did you check all of the clamps/hangers to make sure that everything is 100% secure?

- Have you researched to see if anyone else is runing the same muffler?

- Here is a thread with several folks reporting no issue with Walkers. May be worth reaching out to them. https://forum.ih8mud.com/100-series-cruisers/482719-muffler-replacement.html.

From playing with Corvette Exhausts, I know that resonance can pop up based on make/model at various RPM's, so it could just be a bad pairing between the two.

 

[electro992]

Muffler was put on by a shop, and I've already been back to double check. All the flange bolts are tight, no leaks, rubber hangers in the stock positions. Muffler is very quiet during all other driving. The noise seems to build up as the truck comes to a complete stop until it reaches its max that seems to reverberate the whole car. As soon as the car starts rolling or the RPMs rise just above the idle speed, the vibration goes away. It definitely seems like a resonance issue related to the particular idle RPM, however I am at a loss for how to approach a fix.

 

[Sandroad]

How much of the OEM exhaust system was replaced? Just the muffler, or did they also remove/replace the resonator in the pipe after the muffler? The mechanism on the rear of the OEM muffler is there to prevent resonance like you describe. Even though the shop checked it, you may want to take a look yourself to make absolutely sure there is no metal to metal contact anywhere. Other than those ideas, I wouldn't know where to start the trial and error changes to eliminate resonance. As bad as you describe the resonance, you may want to replace the Walker with OEM.

 

[DJWUZJ]

If you had a shop do it, go ahead and double check their work. Jump down there and wiggle it all around. Someone may have gotten lazy and didnt totally button up a hanger.

There is a difference between resonance and vibration. Resonance is more commonly felt in your rear and in your ears. Vibration is in your rear and on the wheel.

If all else fails, could be a defective Walker unit?

 

[OursSauvage]

I had noise because of this weight (broken it was shaked in the cage when idling, making noise)
I removed it and everything is perfect without it.

just in case, I had bad vibrations few weeks ago, but because of a coil pack

 

[2001LC]

The O2 sensor may be part of issue, a reset may help. Disconnect battery for 30 min, clean & re-grease post. While waiting spray-clean MAF meter, check air filter and clean throttle body. Put a can of 44K in 1/2 tank of gas and drive hard (high RPM = OD off) until empty. It may take computer several tanks of gas before a complete reset. Oh, you do have the so called "flex capacitor" attached to frame on PS.

 

[electro992]

MAF and throttle body have been cleaned, front O2 sensors are new Denso, plugs are new denso, fuel filter and engine air filters have both been replaced. Car runs great at all other RPMs except idle. I do not have any frame weights - does anyone know if there is a Toyota p/n to order one?

 

[2001LC]

Don't know part #, but some here may give you for cost of shipping.

Did you reset; by removing battery cables for the 30 minutes which is per FSM with MAF meter testing. 44K with today's gas "a must" once every year or two, 44K recommends every 6 months.

 

[electro992]

Still trying to chase this down, anyone have one of the frame weights they'd be willing to part with?

Found one, thanks LandCruiserPhil!