Low and high idle

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Sep 4, 2020 | 11:19 AM

BenCramer98

Thread Starter

Junior Member

iTrader: (1)

Joined: Sep 2020

Posts: 24

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From: Illinois

Car: 1986 z28 camaro

Engine: 305 tpi

Transmission: 700R4

Low and high idle

My 86 tpi camaro has always from brand new idled at two different speeds. One faster and the other slower. Was this an error from the factory?

Sep 4, 2020 | 01:29 PM

ULTM8Z

Supreme Member

Joined: Jan 2003

Posts: 4,619

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Re: Low and high idle

Idle speed always varies with coolant temperature for any gasoline powered car.

Sep 9, 2020 | 09:00 AM

KyleF

Senior Member

Joined: Nov 2004

Posts: 768

Likes: 32

From: Lansing, MI

Car: 1988 IROC-Z

Engine: 5.7 TPI

Transmission: 700R4

Axle/Gears: 3.45

Re: Low and high idle

Quote:

Originally Posted by BenCramer98

My 86 tpi camaro has always from brand new idled at two different speeds. One faster and the other slower. Was this an error from the factory?

What ULTM8Z is saying is correct, depending on coolant temp the ECM will target a different RPM to idle at.
Additionally there are two idle speed classifications. One is in P/N the other is in D or in gear.

There is also a bump in idle for AC.

If what you are experiencing relates to the above conditions, everything is perfectly normal. If not, please provide more detail of what you are experiencing.