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15 Z71

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15 Z71 Senior Enthusiast

15 Z71

Posted
Posted

I know people on here can probably answer my couple questions. First,I have a 15 Sierra with a 5.3 why does it idle so fast on cold starts at 1200 rpms for a min or so? Second why do the heated seats only seem to get hot when you are sitting in them. Example,I get out to get gas and get back in seats are not very warm until I sit back down. And yes truck is running. Lol 

1SLOW1500 Senior Enthusiast

1SLOW1500

Posted
Posted

There are if memory servers me right like 5 idle profiles. If truck is in park and is cold started it is looking for the engine temp to get over 160 or 180. But again many profiles. As for seat, there is no pressure switch so I would say your fat ass is a huge insulation and allows the element to trap heat better. 

aseibel Senior Enthusiast

aseibel

Posted
Posted

The seat heating element is under some padding. The surface won't feel hot until you compress the the pad. As long as you can feel the heat after sitting on them for a few seconds, they are operating normally.

diyer2 Senior Enthusiast

diyer2

Posted
Posted

Every newer, computer controlled vehicle I have been around always has a high idle on a cold start.

Lots of variables for this IMO.

Mine the rpms drop after a short time and so have my other vehicles.  

Maybe it takes the computer a little time to get all the info to set the idle correctly.

 

The heated seats are like an electric blanket, much warmer once in the sheets.

Our Honda seats are warmer than my truck seats.

:)

Sierra Dan Senior Enthusiast

Sierra Dan

Posted
Posted

Every vehicle I have owned in recent memory always idle high for 5-15 seconds upon cold startup.

 

As far as seats.... the heated seats are poorly designed in our '14 & 15' trucks. The elements tend to fail often. Mine have been replaced twice.

Especially worse when combined with the cooling seat feature.

'16 and up models work much better as there was some sort of newer update or component design.

 

15 Z71 Senior Enthusiast

15 Z71

Posted
  • Author
Posted
6 hours ago, Sierra Dan said:

Every vehicle I have owned in recent memory always idle high for 5-15 seconds upon cold startup.

 

As far as seats.... the heated seats are poorly designed in our '14 & 15' trucks. The elements tend to fail often. Mine have been replaced twice.

Especially worse when combined with the cooling seat feature.

'16 and up models work much better as there was some sort of newer update or component design.

 

Mine work good in my 15,just thought they would be a little warmer using remote start. 

15 Z71 Senior Enthusiast

15 Z71

Posted
  • Author
Posted
39 minutes ago, 1SLOW1500 said:

8 idles just for coolant temp.9bf19abedf792d9abaa763fc540b3525.jpg

Sent from my SM-N950U using Tapatalk
 

Interesting. Thanks.

  • 4 months later...
14GMCZ71 Enthusiast

14GMCZ71

Posted
Posted

When I obtained my drivers license in 1976 I was driving my parents vehicles until I saved up enough money to buy a Jeep CJ5.

 

I drove a '74 Chevy Caprice with a 400 cu in two barrel carb 3-speed auto and a '74 Ford Pinto Wagon with a 2000cc (122 cu in) two barrel? 4-speed manual - what a power house.

 

Both ran on regular leaded gas - no converters - but man those carbs.  The instructions for cold start on the underside of the driver visor went something like this if memory serves me correctly:

 

Press accelerator pedal to floor and slowly release - press accelerator pedal 1/4 way down and start car.  Release accelerator pedal.  Talk about a high idle!

 

I thought at the time those engines sure had a lot of vacuum lines.

 

Take a look at a 1980 Chevy/GMC 250 cu in inline 6 for some laughs on emissions controls.  The valve cover had these two "metal boxes" on top - something about purge solenoids, etc. and

these metal lines tapped - screwed into the exhaust manifold to inject air? I guess.  All emissions.  And that 250 had integral intake/exhaust manifolds.  The exhaust manifold did split the 6

exhaust ports - 3 into 1 and 3 into 1.  Couldn't put headers on it - had to get another type of head.

 

Ah the good old days.

 

 

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