Engine - Rough Idle/Uneven Acceleration/No Code
89AMCJEEP013E
DECEMBER 1987 442
1988 MEDALLION MODELS WITH MANUAL TRANSMISSION
ENGINES Attention: Workshop, Parts Department
ENGINE DIAGNOSIS
On some 1988 Medallion models with manual transmission, the MS 1700 tester may not indicate a system fault if occasional rough idle/uneven acceleration is experienced with a warm engine.
This condition may be the result of a calibration difference between the oxygen sensor and ECU. Because the difference is so slight, it will not register on the MS 1700 tester.
If the tester does not indicate a system fault and the warm engine condition is experienced, install oxygen sensor module kit, P/N 8983 505 116, as outlined in this I.S. Note.
Figure 1:
The kit contains the following components (Fig. 1):
^ oxygen sensor-voltage limiting module (A)
^ ground wire (B) sensor connectors (C) and (D)
^ voltage source wire (E) for the MAP sensor voltage input wire
FIGURE 2:
KIT INSTALLATION PROCEDURE
1. Open the hood.
2. Disconnect the battery cables.
3. Remove the battery holddown bracket.
4. Remove the battery.
5. Mount the module (A) on the headlight panel as follows (Fig. 2):
a. Mark a spot on the panel ledge (F) 4-inches to the left of the oval opening (G) and 3/8-inch up from the bottom of the ledge.
b. Drill a 3.9 mm (0.1535 in) hole at the marked spot for the module mounting screw.
c. Apply dialectric grease, P/N 812 6688, to the threads of the module mounting screw supplied in the kit.
d. Attach the module (A) and the ground wire eyelet (B) to the panel ledge with the mounting screw.
FIGURE 3:
6. Remove the oxygen sensor connector (H) from the retainer clip on the engine block.
FIGURE 4:
7. Disconnect the oxygen sensor wire connector and install the new harness connectors (C) and (D) (Fig. 4)
FIGURE 5:
8. Route the voltage source wire (E) along the radiator upper crossmember to the driver side of the engine compartment. Position the end of wire (L) in the area shown in Figure 5.
FIGURE 6:
Remove the Wingnut (J) and remove the ECU cover (K) (Fig. 6).
FIGURE 7:
9. Locate the green wire (N) leading to terminal "C" of the MAP sensor connector (M) (Fig. 7).
10. Cut the green wire (N) 1-1/2 inches from the connector.
11. Remove 1/2 inch of insulation from each end of the cut wire (N) with a wire stripper tool.
FIGURE 5:
12. Slide the heat shrink tubing (from the kit) onto voltage source wire (E). Then slide the tubing back from the wire end about two inches to avoid heating the tubing when the wire is soldered.
FIGURE 8:
13. Twist the ends of wire (N) together. Then twist the end of wire (E) around wires (N) to ensure a strong connection (Fig. 8).
FIGURE 9:
14. Solder wires (E) and (N) together with rosin core solder (Fig. 9).
15. Slide the heat shrink tubing over the soldered connection. Be sure the tubing completely covers the solder joint and and any sections of bare wire.
FIGURE 10:
16. Shrink the tubing with a heat gun (R) (Fig. 10).
FIGURE 5:
17. Secure the new harness wire (E) to the radiator crossmember with tie straps (P) (Fig. 5).
FIGURE 4:
18. Coil any excess wire at the oxygen sensor and secure it with a tie strap (Q) (Fig. 4).
19. Install the ECU cover and wingnut.
20. Install the battery hold down bracket. Then install and connect the battery.
PARTS INFORMATION
SRT INFORMATION
OPERATION DESCRIPTION NUMBER SRT TIC
CO. OXYGEN SENSOR 0105 0.5 1-977
MODULE-INSTALL
FILING INFORMATION
Record this I.S. Note on page B-58 of M.R. 289 and file it in the manual.