Curiosii for ever!: Car repair manuals for everyone.
Home >> Mercury >> 1988 >> Merkur Scorpio V6-179 2.9L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Technical Service Bulletins >> Customer Interest >> Engine - Rolling Idle/Surging Condition

Engine - Rolling Idle/Surging Condition


88ford04

^ IDLE ROLL - 2.9L EFI - THROTTLE PLATE MODIFICATION AND EEC IV PROCESSOR -
VEHICLES BUILT BEFORE 9/01/87

^ SURGE - 2.9L EFI - THROTTLE PLATE MODIFICATION AND EEC IV PROCESSOR -
VEHICLES BUILT BEFORE 9/01/87

Article No. 88-5-12

MERKUR: 1988 SCORPIO

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

ISSUE: A rolling idle or surging condition may be caused by an imbalanced airflow between the cylinder banks and the strategy of the EEC IV processor.

ACTION: To correct this, modify the diameter of the air bleed hole in the throttle plate, reset the idle speed and install a new level EEC IV processor. Refer to the following service procedure.

1. Check to see if the vehicle already has the new level EEC IV processor (E8RY-12A650-YA). If the new EEC IV processor is present, STOP here and refer to the Scorpio Shop Manual for normal diagnostic procedures. If the new level processor is not present, proceed to Step 2.

2. Remove the old EEC IV processor.

3. Install the new level EEC IV processor (E8RY-12A650-YA). Remove part of the tear-off tag from the new EEC IV processor and place it over the old tear-off tag on the right "A" pillar.

4. Loosen hose clamps and remove the intake air duct hoses.

5. Locate the air bleed hole in the throttle plate on the left bank of the throttle body. Using a hand drill and a 9/64" (3.5 mm) bit with the flutes filled with grease to retain the shavings, carefully enlarge the air bleed hole in the throttle plate.

6. Carefully remove any remaining shavings. DO NOT remove the oil and carbon deposits from the backside of the throttle plate.

7. Reinstall the air intake duct hoses and tighten the hose clamps.

8. Place the transmission in PARK (automatic transmission) or NEUTRAL (manual transmission) and make sure the parking brake is applied.

9. Warm the engine to normal operating temperature and turn it off.

10. Disconnect the idle speed control valve electrical connection.

11. Start engine and operate at 2000 RPM for about 30 seconds by manually operating the throttle linkage.

12. Set the EATC in the ECON or OFF position.

13. Allow the engine to return to idle slowly and check base idle using an accurate tachometer.

14. Remove the tamper-proof cap from the throttle stop screw and throw it away. Loosen the throttle stop screw lock nut.

FIGURE 4:





15. Loosen the throttle camplate roller bolt prior to adjusting the throttle stop screw, Figure 4.

16. Set the engine idle speed to 700 +/- 25 RPM by adjusting the throttle plate stop screw. Retighten the lock nut on the throttle stop screw.

17. When retightening the throttle camplate roller bolt, make sure that the throttle stop still contacts the throttle stop screw. When the throttle is open, make sure the throttle camplate contacts the roller without excessive throttle pedal "lost motion".

18. Increase engine speed to 2000 RPM for about 30 seconds. Repeat this one more time to make sure the throttle plates are free.

19. Turn off engine and connect the idle speed control valve connector.

20. Check to make sure the throttle plates are not sticking in the bores by moving throttle plates.

21. Restart the engine and set the EATC to the OFF or ECON position.

22. Bring engine up to 2000 RPM for 1-1/2 seconds and release. Allow engine to idle for about 3 minutes.

23. Bring engine up to 2000 RPM for 1-1/2 seconds and release. Place automatic transmission in DRIVE ("D") and allow engine to idle for about 3 minutes.

24. Turn A/C on and allow the engine to idle for about 3 minutes while the transmission is still in DRIVE ("D").

25. With the A/C on, place the automatic transmission in PARK and allow the engine to idle for about 3 minutes.




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

E8RY-12A650-YA EEC IV Processor BG

OTHER APPLICABLE ARTICLES: Supersedes 87-9-9
WARRANTY STATUS: Eligible Under Emission Warranty Coverage
OPERATION: 880512A
TIME: 1.9 Hrs. DLR. CODING: Basic Part No. 9F715 - Code: 09
pro multis · Curiosii