vyper340

Just today my CTT started to make a buzzing honking noise under hard acceleration only. This is after the coil packs and spark plugs were replaced at the dealer. My question is about the possible diverter failure and what that noise sounds like and what conditions bring out that issue? To my knowledge the DV’s have never been replaced and the car just went out of factory warranty with 36k miles (2005 CTT with FVD upgrades; computer, bypass pipes, lowering module).

Slow Guy

Forgive my ignorance (or another senior moment) but what is a DV?

vyper340

No problem. DV=Diverter Valve. All turbo's have them to release the excess pressure created during the boost stages.

Slow Guy

Ah-so, no turbos in my fleet so that was new to me, thanks for the info.

vyper340

I replaced the DV's with EVOMS DV's but still have the noise under boost condidtions. The car doesn't seem to loose power but has the noise. It is not consistent every time so what else could it be???

99firehawk

possible drive shaft bearing failure. get under the car and shake the driveshaft behind the center bearing. if it goes up and down more then 1/2 inch, its shot. makes a lot of noise under hard accel.

vyper340

Thanks but the noise is a buzz reminiscent of a honk like when stock DV's fail. Thanks for the feedback

99firehawk

Are you srue the noise wasnt there before the coils/plugs