Valve Cover - Engine Hesitation/Surge/Stumble

91amcjeep07

NO.: 18-57-91

GROUP: DRIVEABILITY

DATE: Nov. 18, 1991


THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-55-90 WHICH SHOULD BE REMOVED FROM YOUR FILES. THE REVISIONS ARE HIGHLIGHTED IN RED AND >>ARROWS<<.


MODELS:

1989-90 (B2) SUMMIT


>>SYMPTOM/CONDITION:<<

Vehicles equipped with a 1.5L engine and an automatic transaxle, may exhibit a hesitation, surge, stumble, or driveway dieout within the first 60 seconds after a cold start. Vehicles equipped with a manual transaxle may exhibit a surge condition, with engine at full operating temperature, while driving at a steady speed.

NOTE: VEHICLES EQUIPPED WITH AN AUTOMATIC TRANSAXLE EXHIBITING A SURGE AT 45-55 MPH SHOULD HAVE TECHNICAL SERVICE BULLETIN 18-19-90 PERFORMED.

DIAGNOSIS:

Verify the vehicle is functioning as designed using the DRB II, and the appropriate Diagnostic Test Procedure. If no problems are found, perform the repair procedure.


PARTS REQUIRED:

1 Cylinder Head Cover MD168907


REPAIR PROCEDURE:

This repair involves cleaning several engine components of oil and carbon deposits, and the installation of a new style valve cover.

Figure 1:

1. Confirm the air flow sensor identification number (E5TO1571) as marked on the side of the air flow sensor (Figure 1). Inspect the air passage of the sensor and verify that one of the air by-pass holes are plugged. If both of the by-pass holes are open, the air flow sensor must be replaced using the correct sensor, PN MD118125.

2. As outlined in the appropriate service manual, remove the throttle body, air intake hose, intake plenum and intake manifold.


3. Use Mopar Parts Cleaner PN 4318037 or equivalent, to clean oil, and carbon residue from the throttle body and intake system. Do not submerse the throttle body in solvents, gasoline or any other cleaning fluids.

CAUTION: USE THIS CLEANER ONLY IN A WELL VENTILATED AREA. DO NOT LET THIS CLEANER COME IN CONTACT WITH YOUR SKIN. RECOMMEND THE USE OF RUBBER OR BUTYL GLOVES. WASH HANDS THOROUGHLY AFTER USE. AVOID EYE CONTACT. AVOID INGESTING.

4. Using the DRB II verify the injectors are working properly. Replace them if necessary.

5. With the air intake plenum and intake manifold removed from the engine, check the intake valves for carbon deposits. If the valves have heavy deposits (more than a light coating on the valves), the intake valves should be cleaned. The suggested method for cleaning intake valves involves the removal of the cylinder head from the engine. The cylinder head must be disassembled, and the carbon removed from the valves with a wire brush.

6. Inspect the spark plugs for heavy carbon deposits, replace as required.

7. Install the new Cylinder Head Cover, PN MD168907 as outlined in the service manual.

8. Install the throttle body, and the intake plenum in the reverse order it was removed, using new gaskets.

9. Drive the vehicle and verify the condition has been corrected.


POLICY: Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
>>Labor Operation No.<<


Clean engine components, throttle body,
intake system, replace valve cover 09-35-01-91 . . . . . . . . . . . . .2.1 Hrs.

Remove cylinder head and clean intake
valves 09-35-01-92 . . . . . . . . . . . . 2.9 Hrs.


FAILURE CODE: 41 - Foreign Material