Tune-Up - v8 Jeep Wagoneer SJ

ENGINE IDENTIFICATION

Engine can be identified by the fourth digit of engine Build Date Code, located on a tag attached to the right cylinder head cover. The same code letter is also the fourth digit of Vehicle Identification Number (VIN), located on a plate attached to top left corner of instrument panel.

VIN ENGINE CODES

TUNE-UP NOTES

Note. When performing tune-up procedures described in this article, the following notes and precautions must be followed.

Due to production changes, always refer to Engine Tune-Up Decal in engine compartment before attempting tune-up. In the event of a conflict between specifications given in this manual and decal specifications, use the decal specifications.

When performing tune-up on vehicles equipped with a catalytic converter, do not allow or create a condition of engine misfire in one or more cylinders for an extended period of time. Damage to converter may occur due to loading with unburned air/fuel mixture.

ENGINE COMPRESSION

Measure compression pressure with engine at normal operating temperature, spark plugs removed, throttle and choke valves wide open and engine at cranking speed.

COMPRESSION SPECIFICATIONS

SPARK PLUGS

SPARK PLUG SPECIFICATIONS

SPARK PLUG TYPE

HIGH TENSION WIRE RESISTANCE

Do not puncture spark plug wires with any type of probe. Remove spark plug wire and check resistance using an ohmmeter.

RESISTANCE (OHMS)

FUEL PUMP

Perform fuel pump test with air cleaner removed and fuel inlet line or filter disconnected at carburetor. Disconnect fuel return line at fuel filter and plug nipple or filter. Make all tests at idle speed.

FUEL PUMP SPECIFICATIONS

VALVE CLEARANCE

All models are equipped with hydraulic lifters which should be adjusted to zero lash.

VALVE ARRANGEMENT

E-I-I-E-E-I-I-E (Front to rear, both banks)

DISTRIBUTOR

All models are equipped with Solid State Ignition (SSI) systems and no adjustments are required.

Timing Mark & Firing Order (Timing Socket Located at 9.5 Degrees ATDC). Scheme 3

IGNITION TIMING

Note. Engines are equipped with a receptacle for a magnetic probe timing light, located 9.5° ATDC. Do not use this location for timing with a conventional light.

Warm engine and allow to idle. Disconnect and plug distributor vacuum line, then check ignition timing. Adjust by turning distributor.

TIMING SPECIFICATIONS (DEGREES BTDC @ RPM)

HOT (SLOW) IDLE RPM

1. Set parking brake and block drive wheels. Connect tachometer to engine. Warm engine to operating temperature and place in Neutral (manual) or "D" (automatic). Turn hex head screw on solenoid carriage to adjust solenoid RPM. Disconnect solenoid wire and adjust idle speed screw to obtain curb idle.
2. If equipped with dashpot, depress stem fully and measure clearance between stem and throttle lever. Turn dashpot to adjust to .093" (2.4 mm). Tighten lock nut and remove test equipment.

IDLE SPEED (RPM)

IDLE MIXTURE

Note. Be sure idle speed and timing are set before performing idle mixture adjustment. If mixture setting takes more than 3 minutes, run engine at 2000 RPM in neutral for 1 minute, then resume adjustment.

TACHOMETER (LEAN DROP) PROCEDURE

Note. Idle mixture adjustment is not part of a regular tune-up. DO NOT adjust mixture unless carburetor has been disassembled or vehicle fails emissions testing.

1. Warm engine to normal operating temperature. Turn idle mixture screws to full counterclockwise position, note position of screw slot, and remove limiter caps. If screw moved during cap removal, adjust to prior position.
2. Start engine and run in Neutral (manual) or "D" automatic). Turn mixture screw clockwise (leaner) until engine speed begins to drop. Then turn screw counterclockwise (richer) until highest RPM reading is obtained. This is lean best idle. Finally, turn screw clockwise until specified "Lean Drop" is obtained. NOTE: If final RPM differs more than 30 RPM from specified curb idle speed, reset curb idle and repeat mixture adjustment.
3. Carefully install new limiter caps with tabs positioned against full rich stop. Press caps fully into place.

LEAN DROP (RPM)

COLD (FAST) IDLE RPM

Disconnect EGR vacuum line and plug carburetor port. With engine idling at normal operating temperature, place fast idle screw on second step of fast idle cam and against shoulder of high step. Adjust screw to set fast idle RPM.

FAST IDLE SPEED (RPM)

AUTOMATIC CHOKE SETTING

To adjust automatic choke, loosen cover retaining screws and rotate cover in direction indicated by arrow on face of cover. Adjust to specified setting.

AUTOMATIC CHOKE SETTING

All models are equipped with Motorcraft breakerless solid state distributors. No adjustments are required.

TOTAL SPARK ADVANCE @ 2000 RPM

DISTRIBUTOR PICKUP COIL RESISTANCE (OHMS) @ 75°F (24°C)

IGNITION COIL RESISTANCE (OHMS) @ 75°F (24°C)

COIL OUTPUT @ 1000 RPM

ALTERNATORS

All models are equipped with Delco solid state alternators with integral voltage regulator.

ALTERNATOR SPECIFICATIONS (1)

All models use Delco solid state regulators, integral with alternator. Regulator is non-adjustable.

EMISSION CONTROL

Note. See appropriate article in EMISSION CONTROL section.

FUEL SYSTEMS

CARBURETORS

BATTERY

BATTERY SPECIFICATIONS

STARTER

All models are equipped with Motorcraft positive engagement starters.

STARTER SPECIFICATIONS

BELT ADJUSTMENT

BELT ADJUSTMENT (1)

SERVICE INTERVALS

REPLACEMENT INTERVALS

FLUID CAPACITIES