Engine - RPM Flare When Shifting/High Idle Speeds
84ford16Article No. 84-7-14
IDLE - INTERMITTENT HIGH IDLE SPEEDS (2.8L)
LIGHT TRUCKS 1983-1/2-84 RANGER AND BRONCO II
CALIBRATIONS: All calibrations with 2.8L engine.
Higher than normal idle speeds and a RPM flare-up when shifting gears may occur on vehicles with idle speed controls.
If idle speed excursions are present with a properly set TRC screw, replace the current 2-step mechanical fast idle cam with a 4-step cam and reduce the maximum extension of the D.C. idle speed control motor to 1200 RPM. Use the following procedure:
1. Remove the carburetor per 1984 Truck Shop Manual, Section 24-25, page 12.
2. Remove and replace fast idle cam with E3TZ-9597- A per Shop Manual procedure Section 24-25, pages 15-16 for automatic choke service.
a. To check for proper fast idle cam indexing:
^ rotate choke cap 90~ rich (left).
^ cycle throttle to set choke.
^ remove hose and apply vacuum to pulldown (P/D) motor and cycle throttle again. Fast idle adjustment screw must align with the stamped "V" on the fast idle cam. Adjust indexing screw if required.
^ replace P/D vacuum hose and re-index choke cap to proper position.
3. Reinstall carburetor assembly per Shop Manual.
4. Complete the fix by repeating the idle speed set procedure (1984 Car/Truck Shop Manual (H) - Emissions Diagnosis, Section 4, Page 4-79), except in Step 8 of the procedure set engine speed to 1200 RPM (instead of 2000 RPM) with the idle speed control (ISC) bracket screw.
When conducting a EEC Quick Test on vehicles that have been modified with this service fix, it will be necessary to add a .050" spacer between the DC idle speed control motor plunger and carburetor throttle lever. This spacer will provide the increased engine RPM necessary to properly conduct EEC Quick Test.
NOTE: Some engine conditions at idle will cause slight speed variations and should be recognized as normal engine behavior. These small speed
variations are due to the electronic idle speed control and may at time be perceptable to the customer. Even if perceived, these subtle speed changes are not objectionable engine behavior. It is important that the servicing activity be aware of this idle speed control and distinguish between this and real idle concerns identified as above. The engine conditions that will produce these normal idle speed changes are:
^ Cold engine
^ Restat (20 seconds - approximately)
^ Hot engine (above 220 ~F top water)
^ A/C on - includes defrost
^ Dashpot action
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
E3TZ-9597-A Fast Idle Cam C
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP9597B84
TIME: 1.1 Hrs. DLR. CODING: Basic Part No. 9597 Code: H4