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Posts
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All,
My 2022 Sierra SLT makes several pre-start and post shutdown noises right after I open the door. Under the dash, under the hood and under the bed. There is a different set of these noise after I shut it down and exit the cab. I’ve been working on my cars/trucks for some 55 years or so and well, these vehicles are SO different than those just 10 years ago.
Any of you have a feel for what these pre-start and post-shutdown sequences these are?
Thanks in advance.
Gerry-
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When you walk up to the truck with your FOB in hand and open the tail gate, or a door, the fuel pump charges the primary fuel system for the start up process of the engine.
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The noise you hear after shutdown is most likely the vents being cycled behind the dash
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Thanks for the i.d. on these. I need to listen more carefully to another noise it makes a bit after shutdown but only sometimes.
Understand the fuel pump being brought online beforehand is a good addition, with the ‘old’ ignition switch setup the key turning accomplished this same function but not with the same amount of lead time for sure.
The vents cycling after shutdown, that is interesting. GM’s used to use vacuum for some of that and my 2004 Yukon has the stepper type blend doors if I’m not mistaken. Do the newest GM’s not use vacuum for any of the vents? Interesting.
Thanks again!
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Saw this post the other day, took delivery of my Denali Ultimate today. Only driven it a short bit so far but I hear this too. First under the truck near the running boards but AFTER they had tucked in or come out. Then tonight sounded like a bunch of elves busy inside the dash after shutting it down. More so than ANY vehicle I’ve owned to date, this truck clearly has a mind of its own.
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IrwinMFletch, It does pretty much have a mind of its own, lol. But if my experience is similar to yours you will love this engine. I have just under 10K on mine and am so impressed with it. The match up of the engine and 10 speed transmission is so smooth and flawless. I exceed 32 mpg on any trips more than 50 miles and just about 30 mpg around town and shorter trips. Even with diesel prices here $2 a gallon more I figure with the mileage compared to a gasser paying less per gallon but I’m getting upwards of 50% more miles from a gallong of fuel I am at least breaking even. Then if you consider the “suggested” use of premium fuel in the 6.2 I am money ahead. I tow a 30 ft. travel trailer weighing about 8000 lbs. without issue whatsoever. Good luck with yours, keep us posted.
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