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What are these items?
- Thread starter blulite
- Start date
2000StreetRod
Moderator Emeritus
- Joined
- May 26, 2009
- Messages
- 10,597
- Reaction score
- 334
- City, State
- Greenville, SC
- Year, Model & Trim Level
- 00 Sport FI, 03 Ltd V8
variable intake system & IAC valve
See the following: VIS Conversion
The other item in front of the VIS is the idle air control (IAC) valve. The PCM modulates the IAC valve allowing air to bypass the throttle plate to control engine idle speed.
See the following: VIS Conversion
The other item in front of the VIS is the idle air control (IAC) valve. The PCM modulates the IAC valve allowing air to bypass the throttle plate to control engine idle speed.
2000StreetRod
Moderator Emeritus
- Joined
- May 26, 2009
- Messages
- 10,597
- Reaction score
- 334
- City, State
- Greenville, SC
- Year, Model & Trim Level
- 00 Sport FI, 03 Ltd V8
commanded idle speeds
My PCM strategy allows multiple commanded idle speeds:
Idle Speed Neutral = 656
Idle Speed Drive = 624
Idle Speed Adder with A/C On in Drive = 0
Idle Speed Adder with A/C On in Neutral = 0
At cold start idle speed is decreased from fast to normal as engine warms up.
If your idle speed is constant and normal after the engine is warmed up in idle and drive then your IAC is working fine. If the idle speed fluctuates significantly or is excessively low or high then the IAC valve could be defective. Cleaning it sometimes helps if it is sticking. It is an electro-mechanical device that wears with age so cleaning doesn't always solve the idle speed problem.
My PCM strategy allows multiple commanded idle speeds:
Idle Speed Neutral = 656
Idle Speed Drive = 624
Idle Speed Adder with A/C On in Drive = 0
Idle Speed Adder with A/C On in Neutral = 0
At cold start idle speed is decreased from fast to normal as engine warms up.
If your idle speed is constant and normal after the engine is warmed up in idle and drive then your IAC is working fine. If the idle speed fluctuates significantly or is excessively low or high then the IAC valve could be defective. Cleaning it sometimes helps if it is sticking. It is an electro-mechanical device that wears with age so cleaning doesn't always solve the idle speed problem.
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