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Discussion Starter · #1 ·
After replacing the exhaust, loading my tune, and unplugging EGR, I have the following sound out of the exhaust when I start my truck in the morning, cold. When it's warm, it does not make this sound. Flo-Pro down tube back exhaust with a 30" FTE resonator placed behind the straight pipe out of the down tube. I hosted the sound on my soundcloud account - https://soundcloud.com/drummin_man44/truck-bus-saw. Any thoughts why it sounds like a table saw?
By the way, the truck is 100% better after the delete. I will be pulling the EGR off this weekend.
Thanks
Chris
 

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Yea Table saw is good description, never heard a truck like that before. Got get your stethoscope out. Listen to things turning very fast, Turbo, Alternator, other pullies, Trani input and TC. Sounds a lot faster than engine rpm alone.
Load on alt may le tup from charge after start. Turbo blade or bearing. may be , pull hose and listen.
Maybe a boost, exhaust or other leak after delete.
 

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Discussion Starter · #4 ·
It's not under the hood, only through the exhaust. Would those other items come through?
Chris

Yea Table saw is good description, never heard a truck like that before. Got get your stethoscope out. Listen to things turning very fast, Turbo, Alternator, other pullies, Trani input and TC. Sounds a lot faster than engine rpm alone.
Load on alt may le tup from charge after start. Turbo blade or bearing. may be , pull hose and listen.
Maybe a boost, exhaust or other leak after delete.
 

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Can you verify that your exhaust brake is OFF when starting truck? If it's on, try starting it with it off.
This, and make sure it’s not on High Idle either. Mine sounds more like a jet when it’s in high idle, but close enough to that table saw sound you linked that I can hear a similarity.

FWIW, I would double check everything on the exhaust to make sure it’s not touching anything it’s not supposed to. The jet sound is normal for a high idle, I almost wonder if the whine of your table saw is caused by a slight vibration somewhere along the pipe.

BTW, you nailed it with the description of a table saw, I wasn’t expecting the sound clip to sound like that but I’ll be damned :hehe:
 

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Discussion Starter · #6 ·
Yeah, I need to check the torque on the bolts, but it went in really clean, Nothing was touching anything. At first I thought I put the resonator in backwards or something. I was hoping someone heard this and recognized the sound. I'm going to check the position of the turbo vanes when I start it warm and compare that tomorrow when I start it up.

BTW, you nailed it with the description of a table saw, I wasn’t expecting the sound clip to sound like that but I’ll be damned :hehe:
 

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Watch the VGT % position if you are able to in the EZ lynk app to get an idea. Mine does a very fast 85-90% flutter for a short period on all start ups, but that is sounding a lot slower and more deliberate than what mine does. Little bit of a turbo surge is normal on start up, but that sounds a little strange.
 

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Discussion Starter · #9 ·
I was watching the turbo speed this morning, and noticed that when first started, it sat at 8,000RPM. You could hear the whine. If I turned the exhaust brake on, the turbo spooled up to 12K, then back down to 8. When it hit 12K, no noise. On it's way back down to 8k, it started to whistle, and then oscillate a bit. Once warmed up, it was at 18K RPM at idle. I'll check the VGT position tomorrow. I forgot about that today.
 

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I don’t know what everyone else is hearing, but to me, it literally sounds like someone is cutting a piece of plywood with a circular saw next to a running diesel truck. Now, I know exactly what a deleted truck sounds like on a cold day at startup with the exhaust break on, and it doesn’t sound anything like that.
 

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Yea i wonder if it is blades on either side of the turbo contacting the housing/vanes.
 
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Discussion Starter · #14 ·
Hi Norm,
It was the tune. After going through everything I went through to get it resolved, I sent another note to the tuner and asked if he had any ideas. He said he had programmed it in as a "feature" for his tunes. Apparently he had never been in a campground leaving at 6:00 AM and trying not to wake up your neighbors with your table saw exhaust note. Had I known that before hand, I never would have purchased the tune from him. Try reaching out to your tuner and ask them. Send them my sound file if you need to.
Chris
 
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