Engine - Tip In Stumble/Hesitation/Poor Fuel Economy

85ford08

Article No. 85-8-11

HESITATION - TIP IN - 5.0 HO


FUEL ECONOMY - POOR - 5.0 HO

LINCOLN-MERCURY 1985 MARK VII

CALIBRATIONS: 5.0L H.O.
WARNING: This modification is authorized only for the listed engines. Performing this modification on other engine calibrations is unauthorized and could create liability under applicable federal or local laws.

A tip-in stumble or hesitation can result from the heated exhaust gas oxygen (HEGO) sensor not functioning properly due to lack of 12V power supply to the sensor heater. The tip-in concerns may also be calibration related.

FIGURE 10 - CONNECTOR LOCATION:

Inspect for a pin mismatch in the 12-pin connector of the -12A581- wiring harness. The connector is located under the coolant overflow bottle and forward of the shock tower (Figure 10).

FIGURE 11 - INCORRECT PIN LOCATIONS:

If the pin arrangement is as shown in Figure 11, power is not being supplied to the EGO sensor heater.

NOTE: No other service action will be effective until this is corrected.

Rework the connector as follows:
1. Remove the wedge from the engagement end of the connector.

Figure 12 - CORRECT PIN LOCATIONS:

2. Remove the pin for circuit No. 302 (dark blue) and move it to the new location in the same connector (currently vacant), (Figure 12).

3. Reinsert the wedge into the connector.

4. Reconnect harness and test drive vehicle.

5. If the stumble/hesitation persists, perform quick test.

6. If quick test does not identify a malfunction, the concern is calibration-related; replace the processor.

CALIBRATION REMOVE REPLACE WITH
5-22L R0 E53F-12A650-UA E53Z-12A650-UC
(49 State)

5-22M R01 E53F-12A650-VC E53Z-12A650-VD
(California)

Revise the calibration label to 5-22L R10 (49 State) or 5-22M R-10 (Calif.)

Authorized Modifications Decal:

Obtain an Authorized Modifications decal and list the date, dealer number and summary of alterations performed. Select a prominent place adjacent to the Vehicle Emission Control Information decal suitable for installing the Authorized Modifications decal. Clean the area, install the decal and cover it with a clear plastic decal shield.
PART NUMBER PART NAME CLASS

E53Z-12A650-UC Processor (ECA) R
E53Z-12A650-VD Processor (ECA) W

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.

OPERATION: SP12581A85
TIME: 0.4 Hr. DLR. CODING: Basic Part No. 12A581 - Code: K2-M2-P2