• Tiny
  • ab0918
  • 1986 BMW 535

Engine Performance problem
1986 BMW 535 6 cyl Two Wheel Drive Manual 198000 miles

Why do most cars have fast cold idle and a select few don't? Do non-fast idle cars have to run extra rich during warm up? Why don't more cars have the slow cold idle?

Wednesday, May 14th, 2008 AT 7:54 PM

1 Answer

  • Tiny
  • mhpautos
  • Expert
  • 29,842 posts

Hi there,

This is just at the whim of the designer I feel, some cars just use a cold start injector which makes it richer (like an old choke system, others use a idle air by pass system which is more complex and costs more, some of the systems are a nightmare to get right (early Nissan) while Toyota (cold start injector) is a dram and realy give a problem. I don.T know why there are so many different systems about, but I know one thing, each company will say theirs is the best.

Mark (mhpautos)

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Wednesday, May 14th, 2008 AT 9:51 PM

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