i did a dpfi 2 mpfi swap and my eacv isnt hooked up, will that cause it to not run? and what excatly does it do?(if you know)

 

The idle speed of the engine is controlled by the Electronic Air Control Valve (EACV). The valve changes the amount of air bypassing into the intake manifold in response to electric current sent from the ECU. When the EACV is activated, the valve opens to maintain the proper idle speed. After the engine starts, the EACV opens for a certain amount of time. The amount of air is increased to raise the idle speed anywhere from 150 to 500 rpm, dpending on which engine you have. When the coolant temperature is low (the ECU reads this from the Coolant Temp Sensor), the EACV is opened to obtain the proper idle speed. The amount of bypassed air is controlled in relation to the coolant temperature.

the car will run without the EACV being connected - it will just idle lower and throw a Check Engine Light