Engine - Spark Knock/Ping

86ford21 Article No. 86-6-33

SPARK KNOCK/PING (4.9L) VEHICLES UNDER 8500 LBS. GVW

LIGHT TRUCK 1985 E, F SERIES, BRONCO

Spark knock or pinging which occurs at normal operating temperatures may be caused by the following:

^ Initial distributor timing may be out of specification.

^ The vehicle may have the incorrect air cleaner bi-metal sensor. The incorrect bi-metal sensor can result in an overheated air charge which can cause spark knock or pinging.

^ The feedback control solenoid may be stuck in the open position. This results in a lean condition which can cause spark knock or pinging.

Diagnosis and Repair

1. Check and reset initial distributor timing, if necessary. Refer to the Vehicle Emission Control Information Decal for the proper procedure and specification.

2. Check the color coding on the air cleaner bi-metal sensor, the correct sensor will have a black stripe. If it has a yellow stripe, remove it and install the correct sensor, part number D7FZ-9E607-B.

3. Determine if the carburetor feedback solenoid is stuck, by performing EEC IV Quick Test.

a. No codes (system Pass) indicates solenoid is functioning properly. No further action is required.

b. If a code 41 is present, perform pinpoint test HB to confirm that the feedback solenoid is causing the code 41.

If the feedback solenoid is sticking, replace it with a new solenoid E4PZ-9S565-B.

PART NUMBER PART NAME CLASS

D7FZ-9E607-B Air Cleaner Bi-Metal R
Sensor
E4PZ-9S565-B Carburetor Feedback A
Solenoid


OTHER APPLICABLE ARTICLES: None
WARRANTY STATUS: Reimbursable within the provisions of the Warranty and Policy Manual.
OPERATION: SP9565A86 - Adjust timing ignition.
TIME: 0.3 Hr.
OPERATION: SP9565AS1 - Extra time to adjust idle speed to specification.
TIME: 0.1 Hr.
OPERATION: SP9565A1 - Replace air cleaner bi-metal sensor.
TIME: 0.2 Hr. - F Series and Bronco 0.3 Hr. - Econoline
OPERATION: SP9565A2 - EEC IV Diagnosis (Quick Test).
TIME: 0.5 Hr.
OPERATION: SP9565A3 - Replace feedback control solenoid.
TIME: 0.5 Hr.
OPERATION: SP9565A4 - Repeat Quick Test.
TIME: 0.2 Hr. DLR. CODING: Basic Part No. 9S565 - Code: M7