Engine - Hesitation/Stumbles
86ford23 Article No. 86-3-22HESITATION - 5.0L H.O. - NEW ACCELERATOR PUMP CAM
FORD 1985 MUSTANG
LINCOLN-MERCURY 1985 CAPRI
CALIBRATIONS: All with 5.0L H.O. and Manual Transmission
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.
Vehicle hesitation and stumbles during clutch engagement (both hot and cold operation) can be serviced by inspecting certain components and installing a new accelerator pump cam, if necessary.
Corrective Action:
1. Inspect for other possible causes of this concern:
^ Check that the air cleaner hot air tubes are connected at both the air cleaner and at the exhaust manifolds.
^ Check that the vacuum line to the exhaust heat control valve is connected (LH side of engine).
^ Check for manifold vacuum leaks from damaged or disconnected vacuum hoses. Include the 3/8 inch rubber hose connected to the steel tube below the EGR valve. Test the hoses for vacuum leaks by pinching them off near the manifold fittings and noting if this improves idle quality.
^ Inspect the hot idle compensator (HIC) bimetal for damage. The HIC is located in the PCV tube.
^ Measure the carburetor pump lever clearance. Hold the throttle at WOT, manually depress the pump arm, and insert a feeler gauge between the adjustment screw head and the pump arm. The clearance should be 0.015 inch. Adjust as necessary.
2. If the above procedures do not resolve the concern, install a new accelerator pump cam, part number B9TE-9526-A:
^ Remove and discard the existing nylon accelerator pump cam (color coded pink).
^ Position the new B9TE-9526-A cam (color coded green) onto the throttle lever. The relief in the cam should face inward to provide clearance for the throttle return spring.
^ Install the cam retaining screw and tighten to 7.5 in.lbs.
NOTE: Both the throttle lever and the cam have two screw holes, which are numbered on each part. Install the new cam using the No. 1 position on both the lever and the cam (same as original).
^ Cycle the throttle to ensure that no binding occurs. Also, check to see that fuel is discharged from the accelerator pump discharge nozzles when the throttle is cycled.
PART NUMBER PART NAME CLASS
B9TE-9526-A Accelerator Pump BQ
OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP9526A86 - Inspect only.
TIME: 0.3 Hr.
OPERATION: SP9526B86 - Inspect and replace cam.
TIME: 0.5 Hr. DLR. CODING: Basic Part No. 9526 - Code: P2