Not the check valves

[Deuce]

Well I just replaced both check valves and no change. I'm still getting the same hissing on acceleration and decceleration. A/C is still switching to floor on acceleration. I'm also getting a very noticable "flapping" noise from up by the aircleaner (K&N type) or air can upon decceration. Is this normal? This truck is getting to be a real PITA! Next toy will definately be a 60's muscle car. At least I'll be able to understand what's going on under the hood!

 

[turbodog]

Sorry the valves didn't fix it, but it's still got to be a vacuum system problem, sounds like a major leak.

 

[Guest]

The flapping noise is just the air from turbo spool up. When you let off the gas too fast & close the flange the air has to go somewhere so it goes back out the K&N air filter (easy cleaning 8) )

Just get a blowoff valve to fix that issue. With that installed you will here a very nice loud whistle.

 

[Deuce]

Thanks. I'll tinker around with it again today. It drives fine, but it's something I'd like to get taken care of. Enjoy the rest of the weekend.

 

[InvisiBill]

Search for "turbo flutter" for more info on that. When you let off the gas while in boost, the throttle blades slam shut and all the pressurized air is forced back out through the intake. A BOV vents the extra pressure.