Idle sound ?

[Frankf250]

Does anyone know why the sound changes when idling. I have a 07 with MBRP no cat. It will sound like its building up pressure then it lets out and sounds different for a little an does it again. Any one tell me what that is?? Thanks


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[Tuscany]

That's the vanes in your turbo being cycled at idle so that they don't stick from being idled to long. A lot of trucks do it but mine doesn't as my EGR is completely deleted so it doesn't do it anymore. Kinda wish it did as I like how it sounds when it goes from sounding like a jet getting ready to take off to a deep rumble.

[Frankf250]

Ahh cool. Thanks. Had the truck for a year so far and still learning so much.


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[Tuscany]

No problem enjoy it while its running!! lol.

[06F350xl]

Originally Posted by Tuscany

That's the vanes in your turbo being cycled at idle so that they don't stick from being idled to long. A lot of trucks do it but mine doesn't as my EGR is completely deleted so it doesn't do it anymore. Kinda wish it did as I like how it sounds when it goes from sounding like a jet getting ready to take off to a deep rumble.

I had not noticed that my truck stopped cycling after I deleted the EGR... Any idea how to trick it into cycling again? I miss it as well!

[snopro_03]

If you guys reinstall your egr valve and plug it in your turbo will cycle as it did before your delete. Im all deleted i just left the egr valve in my intake and my turbo cycles at idle. When i had the block off plate in my turbo no longer cycled. so just throw your valve in and plug it in if you dont mind it sitting in your intake.

[04cr450]

unless you have an 04 or 03.. My truck(04) cycles and I have a full egr delete with egr not installed

[snopro_03]

Originally Posted by 04cr450

unless you have an 04 or 03.. My truck(04) cycles and I have a full egr delete with egr not installed

My turbo stopped cycling with my egr completly gone my trucks an 03.... It will cycle with the valve in place.

[portcity_gt]

My 03 will only do it on the stock tune, pretty sure it didn't matter if the valve was plugged in or not, but with the tunes the egr is turned off so it dosnt do it. So I guess if you have the 03-04 that won't throw a cel, turn the egr back on in the tune even if its deleted.
My canned sct tunes give me the option to turn egr on or off, so maybe I'll try turning it on even though its all removed from the truck and see what happens.

One thing I did notice while testing my truck when the hpop went out, my Mac tools scanner wouldn't finish the koer self test without the egr plugged in.

[snopro_03]

I know i've tried what your describing portcity with a canned tune. If I had no egr valve in place with egr on in my tune I had no vain cycle . With my egr valve in place, and egr option ON in my tune the vains would cycle. With my egr valve still in place and egr option OFF in my tune I have no cycle. Every truck is different i guess, thats just my experience.