Description

2-Wire Idle Speed Control Solenoid Kit with Weld-On Flange

Idle speed control is an important aspect of any engine management system. On engines with a mechanical cable-type throttle body, when the throttle is closed, a precisely controlled amount of air must be bypassed around the throttle butterfly to allow the engine to maintain a smooth and constant idle for various loads and engine temperatures. The ECU controls a type of  valve to let this air into the intake manifold.

Idle control valves come in various forms including 2-wire solenoids, 3-wire solenoids and stepper motors (usually 4 or 6-wire). It is important to consider the capabilities of the ECU when considering which type of idle control valve to use. With many entry level ECU’s that have a limited number of inputs and outputs available, sacrificing 2 or more ECU outputs to control either a 3-wire idle valve or an idle stepper motor is not an option. Furthermore, due the increased complexity (and therefore, cost) of supporting stepper motor idle control, certain entry level aftermarket ECU’s only support the simpler idle solenoids. Common examples of ECUs that we encounter that fall into this category include the Link G4+ / G4X Atom and Monsoon ECUs. While all other Link G4-series wire-in ECU’s support stepper motor idle control, only idle speed control solenoids can be used with the Atom or Monsoon.

This 2 wire idle air control valve requires a 12V ignition feed and a single pulse width modulated (PWM) low-side driven signal from the engine control unit (ECU), which progressively controls opening of the valve. An internal spring and engine vacuum is used so that no valve closing signal is required from the ECU, meaning only one ECU auxiliary output is required. As the solenoid relies on engine vacuum to close it fully, these valves are not so well suited for engines with long duration camshafts, especially with smaller capacity engines (i.e. around 1600cc and under).

The solenoid included in the kit bolts to the CNC-machined aluminium weld-on flange that can be welded onto an intake manifold.

The kit includes:

For plumbing the idle control valve, common 19mm (3/4″) heater hose can be used to connect the air inlet on the idle solenoid to a suitable fitting ‘Tee’d’ into the intake pipe or throttle body prior to the throttle butterfly. Alternatively, for naturally aspirated applications, rather than drawing filtered air from the intake pipe, an optional filter can be fitted to the solenoid if preferred.

Recommended signal frequency = 120Hz