Engine Controls - Adjustments Mercury Capri III

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. All models are equipped with hydraulic lash adjusters. No adjustments are required.

Scheme 1

1. Place automatic transmission in Park or manual transmission in Neutral. Disconnect and plug hoses attached to vacuum diaphragm assembly on distributor. Connect tachometer and timing light. Turn off all electrical loads.
2. Start engine, and warm it to operating temperature. Ensure idle speed is set to specification, adjusting if necessary. See IDLE SPEED & MIXTURE. Determine initial timing. See IGNITION TIMING table. If base timing is not correct, loosen distributor mounting bolts and rotate distributor until marks align. Tighten bolts to 14-18 ft. lbs. (19-25 N.m).
3. Increase engine RPM while observing timing light. Verify ignition timing advances. For turbo models, go to step 5). For non-turbo models, continue with next step.
4. On non-turbo models, apply 16 in. Hg vacuum to chamber "A". (Scheme 1) Verify timing advances by 26-30 degrees. Remove vacuum source from chamber "A". Apply 8 in. Hg vacuum to chamber "B" while observing timing. Verify timing advances by 3-7 degrees. Stop engine and remove test equipment.
5. On turbo models, apply 20 in. Hg vacuum to advance diaphragm. Verify timing advances by 13-17 degrees. Disconnect vacuum source. Apply 8 psi (.6 kg/cm 2 ) pressure to advance diaphragm. Verify timing retards by 3-7 degrees. Stop engine. Remove test equipment.

Scheme 2

1. Place manual transmission in Neutral or automatic transmission in Park. Turn all accessories off. Locate single-wire Black Self-Test Input (STI) connector, located near master cylinder. Using a jumper wire, connect STI terminal to ground. (Scheme 2) Connect timing light and tachometer.
2. Start engine, and warm to operating temperature. Ensure idle speed is set to specification, adjusting if necessary. See IDLE SPEED & MIXTURE.
3. Check initial timing. See IGNITION TIMING table. White timing mark should align with White mark on crankshaft pulley. If marks do not align, loosen distributor mounting bolts and rotate distributor until marks align. Tighten bolts to 14-18 ft. lbs. (19-25 N.m).
4. Remove jumper wire. Increase engine RPM, and verify ignition timing advances beyond initial setting. Stop engine and remove test equipment.

IGNITION TIMING

IDLE SPEED & MIXTURE

Note. Idle mixture is controlled by ECA and is not adjustable.

Idle Speed

1. Turn off all accessories. Place automatic transmission in Park or manual transmission in Neutral. Set parking brake. Connect tachometer to engine. Warm engine to normal operating temperature. Connect a jumper wire between single-wire STI test connector (Yellow wire on Capri; Yellow/Green wire on Festiva) and ground. (Scheme 2)
2. Locate Idle Speed Control By-Pass Air (ISC-BPA) valve on intake manifold. Remove cap, and adjust idle speed to specification by turning idle air adjust screw on ISC-BPA valve. (Scheme 3) See IDLE SPEED SPECIFICATIONS table. Remove jumper wire.

IDLE SPEED SPECIFICATIONS

Scheme 3

Capri

Note. Throttle Position Sensor (TPS) on Mercury Capri models is preset at factory. No adjustment is required.

Festiva

1. Ensure idle speed and ignition timing are adjusted to specification. Stop engine. Disconnect negative battery cable. CAUTION: DO NOT tamper with throttle stop screw at throttle lever. Doing so may result in damage to throttle body.
2. Unplug Throttle Position (TP) switch connector at throttle body. Insert appropriate feeler gauge between throttle stop screw and stop lever. Check for continuity between specified terminals on TP switch connector. See THROTTLE POSITION SWITCH ADJUSTMENT (FESTIVA) table.
3. To adjust, loosen TP switch attaching screws. Connect ohmmeter between terminals IDL and TL. (Scheme 4) Insert a.020" (.5 mm) feeler gauge between throttle stop screw and stop lever.
4. Rotate TP switch until ohmmeter indicates continuity. Insert a.028" (.7 mm) thickness gauge between stop screw and stop lever. Ohmmeter should indicate no continuity. If ohmmeter indicates continuity, repeat adjustment procedure.

THROTTLE POSITION SWITCH ADJUSTMENT

Scheme 4