Engine - Sustained Spark Knock

Article No:
81-23-15

11/20/81

Subject:
Spark Knock, Sustained

FORD
1982 Granada, Thunderbird with 3.8L engine - all calibrations

LINCOLN-MERCURY
1982 Cougar, XR-7, Continental with 3.8L engine - all calibrations

LIGHT TRUCKS
ALL F-1OO with 3.8L engine - all calibrations

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

Spark knock and/or detonation in subject vehicles may be serviced by retarding initial timing as follows:


1. A low coolant level (1-1/2 to 2 quarts low) may cause spark knocking. Check the coolant for proper level.
2. F-100 Only - Determine if the vehicle is operated under heavy load with low engine speeds ("lugging" on manual transmission). If so, refer driver to the shift schedules published in the Owner Guide.
3. Check engine initial timing to be sure it is set to specification on decal.
4. Check ignition module run-retard (UIC-RR) vacuum switch, if so equipped, is operating. At idle, the initial timing should retard approximately 4° when the vacuum line to the run-retard switch is disconnected.
5. Check knock sensor if operating. Use procedures found in the 1982 Engine/Emissions Diagnosis Manual (California calibrations).
6. If the spark knock still exists, retard the initial timing only to the point required to resolve the condition, but no more than a maximum of 3°.
7. Check idle speeds. Reset as required.





8. Prepare an Authorized Modifications decal (FPS-8262) and list the date of service, dealer number and modifications performed as shown. 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.

WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.

OPERATION: SP-12127-B-82
TIME: 0.7 Hr.

DLR. Coding: Basic Part No. DRIVE - Code: H9