Hello,

I recently had my turbo pedestal out and while it was out i replaced the up-pipes with the bellowed version. I went with the dorman ones as they were only $165 which I figured was worth a shot for that price.

When i installed everything back it went really smooth. everything lines up correctly and i was pretty happy with it. however when i was driving the truck around i noticed a hissing sound that started at 1200 rps and was constant until a WOT run rpms about 2400 or so. when i let my foot off the pedal the hissing returned.

This morning I started the truck up again(while its cold) and watched the ebpv rod to see if it was functioning. Initially the rod cycled in and out several cm and then stayed in the extended postiion. I think this would be with the valve closed to help with warm ups? Anyway I went away for a half hour or so and checked the position of the ebpv rod again and found that it had retracted back into its housing. At this point I was pretty convinced the ebpv was working correctly.

My next target was the up-pipe collector to check and see if I had it lined up and flush with the turbo exhaust housing. I found that the lug had not lined up correctly so there was a small gap between the housing and the collector. I loosened the up-pipes at the manifolds, loosened the collector v-clamp, and then I got the collector seated correctly on the turbo. After everything was buttoned back up my hissing sound still remained.

So I'm looking for thoughts on what could be causing this leak. Im not 100% on how the ebpv operates but I am pretty sure that if the up-pipes were leaking that I would hear them constantly and the sound wouldn't disappear at higher rpms. My thought is the ebpv is stuck closed partially until wot. I have no idea why this would happen so please educate me. Thanks!

 

I had the same problem with my Dormans, but I didn't have the collector and the turbo lined up right. It's very difficult to get it lined up correctly. I loosened up everything like you did, re aligned it, and found out it was still off. Once I did get it, the hissing went away completely. Not saying you got it wrong again, but maybe it's worth another look...

 

ya its definitely gonna have to come off again either way. either to fix the ebpv or align the collector.. I think ill just rebuild the ebpv for peace of mind and hopefully ill get it lined up correctly this go round. unless someone else pops in with an idea. Appreciate the thought especially since you used the dormans as well. Thanks!