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

Compression

Check engine compression with engine at normal operating temperature at specified cranking speed, all spark plugs removed and throttle wide open.

Specifications:

Range: 145-190 psi (10.0-13.0 kg/cmý)
Ratio: 9.0:1

Valve Clearance

All years have hydraulic lifters. No adjustments are necessary.

Ignition Timing

NOTE: Basic timing readings are only valid when engine idle speed and idle mixture are within specifications. For best results, manufacturer recommends ignition timing, idle CO and idle speed be checked and adjusted in that order.

Check timing advance only after determining that the basic ignition timing is adjusted to specification. With the engine running at normal operating temperature, briefly raise engine speed to above 3000 rpm, repeating this step 4 times. Then let the engine idle for at least 2 minutes.

Disconnect the coolant temperature sensor connector. Raise the engine speed to 2300 rpm, and record timing value. Reconnect coolant temperature sensor connector and briefly raise engine speed above 3000 rpm to store knock sensor information in memory. Raise engine speed to 2300 rpm and recheck timing. It should now be 30°+/-3° more advance than it was with coolant temperature sensor connected.

If timing does not advance as specified, first check knock sensor mounting bolt torque, then check knock sensor resistance and wiring. If torque and resistance are within specification and there are no breaks in wiring, then Digifant control unit is probably fault.

If connecting or disconnecting coolant temperature sensor has no effect on timing advance, check continuity of coolant temperature sensor wire. If there are no breaks in wire, then either Digifant control unit or temperature sensor is faulty.

Engine oil temperature must be 176° F (80° C). Connect timing light and tachometer. Start engine and allow to idle. Check ignition timing at 800-1000 RPM.

NOTE: Before checking engine timing, raise engine speed above 2100 RPM at least 4 times. This must be done each time ignition is turned off and restarted to clear ECU memory and by-pass hot-start, fast-idle function.

If an adjustment is needed, turn ignition off and loosen distributor hold-down bolt just enough to move distributor by hand. Remove connectors from idle stabilizer by squeezing connectors then pulling apart. Plug idle stabilizer connectors together.

Start and allow engine to idle. Turn distributor until notch on V-belt pulley matches separation in case. Set timing and RPM. Reconnect electrical connectors to idle stabilizer. Tighten distributor clamp bolt.

IGNITION TIMING TABLE (Degrees BTDC @ RPM)
Application	Checking	Adjusting
2.1 Liter	4-8 @ 800-900	5-7 @ 800-900

Idle Speed & Mixture

Warm engine to normal operating temperature. Engine oil temperature must be at least 176°F (80°C). Connect an inductive tachometer to ignition coil, and timing light lead to No. 1 spark plug wire. Start engine and ensure engine speed and timing are correct. If speed and timing are incorrect, adjust to specification.

Remove connectors from idle stabilizer by squeezing connectors then pulling apart. Plug idle stabilizer connectors together. Turn idle speed screw until idle speed is correct. To adjust timing, see CHECKING & ADJUSTING under IGNITION TIMING in this article.

Ensure all vehicle electrical equipment is off. Place exhaust gas analyzer in exhaust pipe. See IDLE SPEED & CO LEVEL table. If adjustment is needed, go to next step.

If adjustment is needed, remove intake air sensor from engine. Center punch plug in CO adjusting hole. Using a 3/32" drill bit, drill hole 5/32" (4 mm) deep in center of plug. Remove any metal shavings. Install a sheet metal screw and, using pliers, pry out plug.

Disconnect oxygen sensor connector on left side of engine compartment (Green wire). Start engine. Set idle speed and CO reading by alternately turning mixture and idle speed adjustment screws. Reconnect oxygen sensor and idle stabilizer connectors. Let engine idle for 2 minutes.

Check CO value. If incorrect, repeat adjusting procedure. If correct turn ignition off. Drive in new adjusting hole plug flush with air intake sensor. Remove all test equipment and reconnect all hoses and wiring.

IDLE SPEED & CO LEVEL TABLE
Application	Idle RPM	CO Level %
2.1 Liter	830-930	0.3-1.1

Throttle Stop Screw

NOTE: Stop screw is set by manufacturer and should NOT be moved.

If basic factory setting has been changed, turn throttle stop screw counterclockwise until there is a gap between stop and screw. Turn screw in until it just touches stop. Turn screw 1/2 turn (180 degrees) further. Check and adjust idle speed and CO.

Idle & Full Throttle Switch

Idle and full throttle switches are wired in parallel on throttle valve assembly. Disconnect throttle valve connector from throttle valve switch. Connect voltmeter between terminal in harness connector. Turn ignition on. If 5 volts are not present, check for break in wiring and repair. If no break in wiring, replace Digifant II control unit and recheck.

Circuit should be closed when throttle is at rest. Check continuity between test harness terminals No. 1 and 2. If switch-on point is incorrect, loosen and adjust idle switch position. Recheck clearance between throttle valve lever and stop. Ensure clearance is . 002-.006 (.15-.05 mm). Throttle switch is located on underside of throttle valve housing, opposite idle stop.

Air Flow Meter Potentiometer

Airflow potentiometer is factory adjusted. No adjustment is needed.