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5.3 v8 idle

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by silverbike9, Sep 13, 2012.

  1. silverbike9

    silverbike9 New Member

    Does anyone know why the 5.3 idles in v8 mod? My guess is so the power is there to start out safely. Is there a programer that will let it idle in v4?
  2. Justice17

    Justice17 New Member

    what year is your truck? my truck idles a little low also and ive been kinda wondering about that. i know cadillac re-introduced the cylinder shut off system in the mid 2000's but im not sure if chevy/gmc adopted it as well.
  3. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    I suspect it's a temperature thing. In V4 mode, 4 cylinders do not fire and the block heats unevenly, extended idling would cause distortion.
  4. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    This is what I suspect also, in V-4 mode I dont believe it retains enough heat in the engine block to keep everything at the temperature required.
    I did some studying about the AFM system (gotta find the site I was looking at again) but during testing they found if the engine block was only hot in certain sections and then rapidly heated or cooled they had terrible results, just the water from the cooling system and residual heat from the operating cylinders didnt keep temps where they needed to be. In one picture there were rows of engines that were destroyed during testing and development they were destroying engines at one point at a rate of 10 a day attempting to develop the best methods for operation.
  5. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    They still don't have it right (IMO)........keep it in V8 mode as much as possible.......drive it like ya stole it.

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