Fuel/Ignition - Spark Knock/Detonation
83ford16 Article No. 83-9-13SPARK KNOCK/DETONATION 3.8L WITH AUTOMATIC TRANSMISSION
LIGHT TRUCKS 1983 F-100
CALIBRATION: 3-56D
If spark knock is experienced on the subject vehicle/engine calibration, the following fuel and spark checks can be made to minimize the concern.
1. Prior to making any adjustments to timing or idle speeds verify:
^ The proper grade of fuel is being used.
^ The specified coolant level is maintained.
^ The EGR valve is functioning properly.
2. Verify the initial timing is set to 10~ BTDC.
NOTE: This calibration uses a dual diaphragm distributor. Both the vacuum advance and vacuum retard lines must be disconnected and plugged prior to checking/resetting the initial timing.
3. Verify that curb idle is 550 +/- 50 rpm and A/C kicker idle is 650 +/- 50 rpm.
NOTE: Excessively high curb or A/C kicker idle speeds may result in an artificially high initial timing take-off point resulting in a tip-in spark knock condition.
4. If spark knock persists, retard the initial timing 2~ from the specified initial timing (10~ BTDC). Reset the curb, A/C kicker and fast idle speeds if necessary.
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.
OTHER APPLICABLE ARTICLES: 83-3-28
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: M
TIME: "Actual Time" as defined in the Warranty and Policy Manual. DLR. CODING: Basic Part No. 12127 Code: H9