Idle Adjustment

[George Robinson]

I am attempting to adjust my idle speed according to one of the projects that I found. In the project, it says to disconnect the wire from the ISC Idle Air Bypass Solenoid and then start the truck without using the accelerator. My truck won't start at all. What does this mean?

 

[Richard L]

It means that your truck uses the Idle Air valve to get sufficient air to allow the engine to idle. This is electronicly controled by the ECU and you should not attempt to adjust the idle on the throttlebody linkage.



Our Sport Tracs require that the throttlebody plates be closed which nearly eliminates any air from entering through the throttlebody butterfly valve. The only way the engine can idle is to get air through the IAC (idle Air Control Valve)



If your engine is idling slow or rough, you may need to clean your IAC, but don't attempt to speed up the idle by ajusing the linkage to crack the TB butterfly open.



...Rich

 

[Kevin Palmer]

I am with Rich on this one.



If you ned to adjust your idle you have some sort of an issue.



First check the infamous broken vacuum elbow and also cleanthe IAC...