Wait for idle to slow before putting in gear?
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    1. #1
      Junior Member
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      Mar 2016
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      Wait for idle to slow before putting in gear?

      I have a 2012 S60 T5. On cold start the idle is about 1500 rpm and then drops after about 30 seconds (which I understand is normal). Can the car be put in reverse immediately, or is it better on the engine and/or transmission to wait until the idle speed drops?

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    3. #2
      Junior Member volvoxc9008's Avatar
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      Quote Originally Posted by ryb97001 View Post
      I have a 2012 S60 T5. On cold start the idle is about 1500 rpm and then drops after about 30 seconds (which I understand is normal). Can the car be put in reverse immediately, or is it better on the engine and/or transmission to wait until the idle speed drops?
      I always wait for the car to idle down unless I'm in a hurry. I don't know what the reason is though, my mom just taught me to alway do this when she taught me to drive and it's a habit I just haven't broken.

    4. #3
      Junior Member
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      You can drive right away. It is actually better not to wait. The revs are up to heat up the catalysator .

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    6. #4
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      I don't know for certain, but it sure seems to me that the Volvo (or Bosch?) engineers created a software feature that detects gear selection (Park, Neutral, Drive, Reverse) that accommodates the the scenario you describe. After a cold start, the idle speed is elevated for emissions reasons as wertzius correctly states. They need to get those cats up to working temperature quickly to meet the emissions standards. In fact, the emissions systems are so effective these days that most of the emissions that are generated during the EPA drive cycle are created in that short period before the cats light off! But I digress...

      I noticed that if you are in that period of elevated idle speed, the idle speed will drop the instant you move the gear lever from P to R or D. This prevents that unseemly bump or lurch that happens when the transmission drops into gear from a high RPM. It adds a bit of refinement to the process.

      I can contrast this to the relatively crude idle controls on my 2009 Pontiac G8 V8. Like every other car, the idle speed is higher until the cats light off. Unlike my wife's Volvo, however, the idle speed does not drop merely because you selected Reverse to back out of the garage. All I can say is that you better have your foot FIRMLY on the brake when you pull it out of Park.

      There's nothing technically wrong with the way Pontiac chose to do it, but it definitely puts a little frown on your face when the car makes that big lurch.

    7. #5
      Junior Member
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      Quote Originally Posted by volvoxc9008 View Post
      I always wait for the car to idle down unless I'm in a hurry. I don't know what the reason is though, my mom just taught me to alway do this when she taught me to drive and it's a habit I just haven't broken.
      Same here, do it with both our vehicles, always have done. I have also just started it and gone if in a hurry, but 99% of the time I wait for the idle to drop.

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