250 Cold start idle drops from 1200 to 950 RPM immediately?

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by HASLE, Jan 14, 2020.

  1. Hey guys!

    When I start my 250 in the morning, it idles at 1200 RPM as it should, but only for a second or two, then it slowly drops to 1000-950, until settling around 830-750 RPM after a minute or so. Is that normal behaviour?

    From what I've heard described, it should be staying at 1200 for longer? Doesn't seem to matter if I'm in Sport mode or not. Car is a stock, unmapped 250, with a K-tec cat back as the only real modification.
  2. Sounds normal... My r26 does that.

    Are you finding that it splutters or struggles when opening the throttle?

    If it's driving normally then chances are there's nothing wrong.

    Sent from my CLT-L09 using Tapatalk
  3. Mapped?

    The tuner maybe delete the cold start because its more stress for the engine without personally benefits.

    The cold start (meaning high Rev at start) warm up the Cat fast to get good emission values but on costs of wear to the engine.

    Some engines also had a secondary air pump which press air in the cat and warm it even more up. (Mazda rx8, BMW e46 are which I know immediately)

    If no than it wasn't that cold to made the ecu to start a Cold start script.

    In short everything is Fine :grin:

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