Airflow Sensor & Mixture Control Unit

Remove the duct from top of airflow sensor. Turn on ignition for about 5 seconds and then switch it off. Remaining fuel pressure in system will press control plunger against sensor plate lever.
Lift sensor plate by hand, magnet or pliers (push sensor plate down on 260 Series). A steady resistance should be felt as a result of control plunger action. See Fig 1.
No resistance should be noticed when sensor plate is suddenly pushed down and is not acting against plunger (released or pulled upward on 260 Series). If sensor plate is hard to move, replace entire sensor unit. If control plunger is hard to move, replace fuel distributor.
NOTE: On Saab and Volvo 240 series, air flows from air cleaner UP through air sensor to intake manifold. On Volvo 260 series, air is drawn DOWN from the air cleaner, through throttle valves and to intake manifold.
Be sure sensor plate is centered in the air venturi. Check for uniform clearance around edge of plate. If necessary, loosen retaining bolt in center of plate, adjust plate for 0.010" (0.25 mm) clearance at all points around plate. Use locking compound on centering bolt threads and tighten bolt.
Turn ignition OFF, so that fuel pump is inoperative. Check rest position of airflow sensor plate. See AIRFLOW SENSOR PLATE REST POSITION table . Top of plate should be no higher than the bottom edge of air venturi.

Fig 1: Checking Operation of Air Flow Sensor Plate
Courtesy of NOT AVAILABLE
On Saab and 240 Series, bend wire clip beneath sensor plate and lever (if necessary). See Fig 1. On Volvo 260 Series, check that plate stop does not touch plate. Contact pin is adjustable inward using a drift and mallet (tap lightly). To drive pin outward, air sensor must be removed.

AIRFLOW SENSOR PLATE REST POSITION

Application		Lowest Maximum Position
Saab		020" (.50 mm)
Volvo
	240 Series	040" (1.0 mm)
	260 Series	020" (.50 mm)