Even when the engine is cold, some vacuum is applied to the diaphragm, and the excess is released. During engine start, all vacuum is released, which is carried out by the starter solenoid valve, which is activated during starter operation. This valve should only operate when the ignition key is in the START position (start). Malfunctions of this device can lead to difficult starting of a cold engine. The blue/red wire on the main connector of the solenoid control unit, located on the thermal barrier, goes to the indicated vacuum release starter valve.
Health check
1. When the engine is cold, disconnect the hose from the diaphragm valve and connect the hand pump. With the ignition system disabled so that the engine cannot start, turn the ignition key to the START position. There should be no vacuum on the diaphragm, as the solenoid valve must be turned on.
2. Disconnect the hose from the exhaust manifold and evacuate the diaphragm to vacuum through this hose. The vacuum should stabilize in the range of 102-203 mm Hg, at which the diaphragm should pull the damper lever.