Jeep Cherokee
 Service Manual
Engine » 4.0L engine » Service procedures
Engine performance

It is important that the vehicle is operating to its optimum performance level to maintain fuel economy and the lowest emission levels. If vehicle is not operating to these standards, refer to Engine Diagnosis outlined in this section. The following procedures can assist in achieving the proper engine diagnosis.

(1) Test cranking amperage draw. Refer to Electrical Group 8B, Cold Cranking Test.

(2) Check intake manifold bolt torque; Refer to Group 11, Exhaust System and Intake Manifold.

(3) Perform cylinder compression test. Refer to Cylinder Compression Pressure Test in the Engine Diagnosis area of this section.

(4) Clean or replace spark plugs as necessary and adjust gap as specified in Electrical Group 8D.

Tighten to specifications.

(5) Test resistance of spark plug cables. Refer to Electrical Group 8D, Spark Plug Cables.

(6) Inspect the primary wires. Test coil output voltage and primary resistance. Replace parts as necessary.

Refer to Electrical Group 8D, for specifications.

(7) Test fuel pump for pressure. Refer to Group 14, Fuel System Specifications.

(8) The air filter elements should be replaced as specified in Lubrication and Maintenance, Group 0.

(9) Inspect crankcase ventilation system as out lined in Group 0, Lubrication and Maintenance. For emission controls see Group 25, Emission Controls for service procedures.

(10) Road test vehicle as a final test.

    More about «Service procedures»:

    Valve timing

    Valve service

    Piston fitting

    Piston ring-fitting

    Fitting connecting rod bearings

    Fitting crankshaft main bearings

    Form-in-place gaskets

    Engine performance

    Honing cylinder bores

    Repair damaged or worn threads

    Service engine assembly (short block)

    Hydrostatic lock

    Engine oil service

    Jeep Cherokee Service Manual / Engine / 4.0L engine / Service procedures / Engine performance

    Jeep Cherokee Service Manual


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