ECM/EGR/Throttle Body - Driveability Concerns

91chrysler07

NO.: 18-13-91

GROUP: DRIVEABILITY

DATE: Sept. 9, 1991


SUBJECT: Sag, Stumble, Hesitation During Initial Start-Up and Light Throttle Tip-In Vehicles With 3.0L Engine


MODELS:

1987-88 (S) DODGE CARAVAN/GRAND CARAVAN/CARAVAN C/V VOYAGER/GRAND VOYAGER
1988 (C) DODGE DYNASTY/NEW YORKER


THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-25-90, WHICH SHOULD BE REMOVED FROM YOUR FILES. ALL REVISIONS ARE HIGHLIGHTED WITH >> ARROWS <<.

>> THIS BULLETIN DOES NOT APPLY TO VEHICLES EQUIPPED WITH A CALIFORNIA EMISSION PACKAGE <<.


SYMPTOM/CONDITION:

Vehicle sag, stumble, or hesitation during initial start-up and drive away. This condition only occurs on very light throttle tip-in during the first 1-1/2 to 2 minutes after overnight soak and/or after a 15 to 20 minute hot shut-down.

If this condition is present and ALL the DRB II Driveability Diagnostics indicate no fault codes present, perform the following procedure.


PARTS REQUIRED:

1 Rubber Cap 3/16" Diameter 3580171
1 Single Module Engine Controller

1987 S-Body, >> Federal << 5276431
1988 S-Body, >> Federal << 5276435
1988 C-Body, >> Federal << 5276442

1 Mopar Parts Cleaner 4318037
1 Gasket, Throttle Body Base 4300071
1 Scotch Brite Pad
1 Authorized Modification Label 4275086


REPAIR PROCEDURE:

This procedure involves the removal and cleaning of throttle body bore and blade, disconnecting EGR vacuum line, plugging EGR vacuum port, and replacing the Single Module Engine Controller.


1. Remove the throttle body from intake manifold.

2. While holding the throttle open, spray the entire throttle body bore and the manifold side of the throttle blade with MOPAR Parts Cleaner.

USE ONLY MOPAR PARTS CLEANER, PN 4318037. DO NOT SUBMERSE THE THROTTLE BODY IN SOLVENT, GASOLINE OR ANY OTHER CLEANING FLUIDS.

CAUTION: USE THIS CLEANER IN A WELL VENTILATED AREA. DO NOT LET THIS CLEANER COME IN CONTACT WITH SKIN. RUBBER OR BUTYL GLOVES ARE RECOMMENDED. WASH THOROUGHLY AFTER USE. AVOID EYE CONTACT. AVOID INGESTING.


3. Use a small (1" x 1") piece of Scotch Brite Pad to clean the throttle body bore and throttle blade. While holding the throttle open, clean both the top and bottom of the throttle body bore. Also, clean the manifold side and edges of the throttle blade.

NOTE: IT IS IMPORTANT THAT THIS CLEANING OPERATION BE PERFORMED THOROUGHLY AND COMPLETELY. THE EDGE OF THE THROTTLE BLADE AND THE PORTION OF THE THROTTLE BODY BORE THAT IS IN THE CLOSEST PROXIMITY OF THE CLOSED THROTTLE BLADE ARE THE MOST CRITICAL AREAS WHERE CLEANING SHOULD BE CONCENTRATED. THESE AREAS MUST BE FREE OF ALL DEPOSITS WHEN CLEANING IS COMPLETE.


4. Spray the throttle body with MOPAR Parts Cleaner, and then blow dry with compressed shop air. Inspect for any foreign material which may have been left behind from the cleaning process.

CAUTION: DO NOT APPLY SHOP AIR PRESSURE DIRECTLY INTO THROTTLE SHAFT AND THROTTLE BODY HOUSING HOLES.

5. Install throttle body, using a new throttle body base gasket, PN 4300071.

6. Install rubber cap, PN 3580171, over the EGR signal port on the throttle body.

7. Tape the EGR signal line to the canister purge hose.

8. Replace the Single Module Engine Controller (SMEC), using the appropriate unit called out in PARTS REQUIRED.

9. Verify the minimum idle airflow RPM is within the specifications outlined in the appropriate Diagnostics Procedure Manual.

Figure 1:

NOTE: FOR THE 1987 "S" BODY, USE THE 1983-88 DRB II CARTRIDGE AND THE 1987 3.0L EFI DIAGNOSTIC TEST PROCEDURE MANUAL (PUBLICATION # 81-699-7037) AND PERFORM DRIVEABILITY TEST 22. FOR THE 1988 "C" BODY, USE THE 1989 DRB II CARTRIDGE AND THE 1989 POWERTRAIN DIAGNOSTIC PROCEDURE MANUAL (PUBLICATION # 81-699-9016) AND PERFORM TEST DR-35. FOR THE 1988 "S" BODY, USE THE 1989 DRB II CARTRIDGE AND THE 1989 POWERTRAIN DIAGNOSTIC PROCEDURE MANUAL (PUBLICATION # 81-699-9017) AND PERFORM TEST DR-36.

10. Type Authorized Modification Label, PN 4275086, as shown in Figure 1 and attach near VECI label.


* INSERT PART NUMBER USED.

** INSERT "1983-88 DRB II CARTRIDGE" WHEN USING PN 5276431, AND INSERT "1989 DRB II CARTRIDGE" WHEN USING PN 5276435 OR PN 5276442.


POLICY: Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No. 08-19-01-98 . . . . . . . . . . . . . . . . . . . 1.6 Hrs.


FAILURE CODE: NP - Sag or Hesitates