Air/Fuel Mixture Control (Air-Flow Sensor)
- Remove rubber bellows to expose air-flow sensor plate. Disconnect electrical connectors on auxiliary air valve and control pressure regulator, then operate fuel pump for ten seconds to build up control pressure.
Use care not to drop control plunger when removing fuel distributor.
- Using extreme care not to damage sensor plate, lift sensor plate slowly with magnet or pliers. Constant resistance due to control plunger pressure should be felt throughout range of lift. Release plate slowly, lever and control piston should follow. See Figure.
- Lift plate, then return it rapidly to lower position. The piston moves more slowly and should be heard hitting the lever. If not, control piston is sticking.
- Remove 3 screws from fuel distributor and lift off of air flow sensor housing. Be careful not to drop control plunger. See Fig 1.
- Clean plunger in solvent. Remove any deposits with finger nail; DO NOT use tools. Slide plunger in and out while turning it. If any sticking or binding is felt, replace fuel distributor.
- Reinstall fuel distributor. Check air flow sensor plate alignment. Plate should be even with bottom rim or 0.02" (0.5 mm) lower. If not, bend spring clip to correct, or reposition stop pin (tap lightly with punch). See Figure.
- Plate should be centered in housing. If not, loosen center screw and align plate with 0.004" (.1 mm) feeler gauge at four points around rim. Apply Loctite to screw and install and tighten.