I installed a new 4" exhaust (turbo back) a couple weeks ago. From The first time I started it, to now, it makes this high-pitched whine immediately after start up. Actually it sounds more like a jet engine. It only lasts about 5-10 seconds though. And there are no leaks. BTW, I deleted the cat.

It sounds like the turbo. Is it because the turbo isn't so restricted now? I'm puzzled.

 

Sounds like the Exhaust BackPressure Valve. That's exactly what mine sounds like.

 

So how did you determine that? Or, what to do now?

 

Try tieing it open with a piece of wire. That's what I did...

 

I just unhooked my temp sensor that is at the base of the airbox and all is well. It will give you a code when you read it, but it runs fine, even all the way through winter where it was really annoying.

 

hm. double post.

 

upon every cold startup (when i still had the stock turbo with EBPV) it would close for about 5 seconds or so, about 3-4 seconds after startup. i think it does it everytime to check for proper operation. it then goes away. do you hear a loud hissing sound?

 

"immediately after startup" - do you mean after ignition but still at idle or after you start driving? Also, is it a roar type noise or a high pitched whirring? A roar would indicate possibly the EBPV if your air temps are quite low - typically below 30 or so. A whirr would be the turbo. With a cat delete 4" dp and exhuast you will hear the turbo a lot. With stock dp and exhaust you will not likely hear it at all so now you discover new noises.

 

After installing my exhaust system I could hear the same thing. It is most certainly the EBPV. It makes kinda of whoooshing sound when it opens, and has an odd sound before it does. After that however its all turbo!

 

Thanks, but can y'all tell me why this happens? Maybe even how the EBPV works. I have yet to invest in a repair/service manual for the engine. The same thing happens to my buddies' trucks, and they haven't encountered any problems.

 

the EBPV is a butterfly valve that closes when the air temp gets to a low point so that the engine will warm up faster. From my experience the time difference is immeasurably small. I disconnected mine at the 2 prong plug at the base of the turbo on the driver's side 2 years ago and have never had any problem since. Unless your air temps at startup are pretty cold it should not activate. If your temps are higher than roughly 30 either the sensor is defective and it is activating or you are hearing something else. You didnt answer my question in the earlier post so I cant be sure at this point.

 

I was told that the spring in the butterfly valve gets weak so the flap won't operate properly. Common problem apparently...

 

Well, Thanks for the info and...

"immediately after startup", means, " immediately after startup". Not, after I start driving. I guess the sound is more of a roar, but it also sounds like there's bb's going through it. It's just something I've never heard before, and if most of the guys that posted agree it's the ebpv, then it probably is. Thanks again for the "how it works" blurb.

 

Clearly from what you asked originally my question was legitimate. Your turbo doesnt spool "immediately after startup" now does it? If you are going to be snide about offers of help, you wont get any.

 

Dude, chill out. I appreciate your help, but let it go. Catch ya in another thread