Fast idle Solenoid

[chris989]

Hello All,

Does anyone know of, or has ever seen a fast idle solenoid for TBI set ups. Think of a tow/boom truck or ambulance. There are a multitude of industries that need to manually increase the RPM to operate. What did they do in 1989 for this.

I have had enough with my IAC and computer. I am convinced that somewhere within the idle logic my computer adds steps i do not need.
The motor is running perfect, idles perfect all day long, and one variable will click and the IAC wants to idle at 850 warm and 1200 cold. When i gear at a red light, I can watch the IAC add steps trying to reach 850, so much it wants to drag me through the intersection.

Ultimately i would like to disable the IAC parameters and have it only operate steps/coolant and call for AC but i can not figure out how to turn off all of the other layers of garbage.

Until then I have zero'd out my IAC, unplugged it and set the idle to 725 in neutral. I idle at 650 in gear and it is a dream come true. So until i figure out the idle logic or deem my computer defective, I was thinking of adding a Solenoid. setting it to activate for cold start and AC.

Anyone ever see one on a TBI.

https://www.holley.com/products/fuel...ge/parts/46-74

[andyh1956]

I'm curious how you "Set The Idle".
Did you do it using the TPS screw?

[chris989]

Originally Posted by andyh1956

I'm curious how you "Set The Idle".
Did you do it using the TPS screw?

I set the idle just like you would a carb. There is a crew on the driver side of the TBI.

Ground out the pins under the dash, turn key on, remove IAC wire connector, turn off key and remove the jumper from the pins

[D13]

The IAC is the fast idle control. By your description it's trying to keep the idle when commanded. At 850rpm the truck should not have a big torque pull, that is well below the converter flash.

When it is idling perfect, in gear, what RPM does it do? Then ask the question, 'what parameter changed to make it want to idle higher'. If the ECM is commanding it, then the ECM thinks something is going on. RPM, coolant temp, false road speed come to mind quickly, or falling out of closed loop due to a marginal O2 sensor.