Radio - Engine Ignition Interference On AM/FM Band
Article No.96-8-14
04/08/96
^ NOISE - "ENGINE IGNITION" STATIC HEARD THROUGH RADIO (AM OR FM) - VEHICLES WITH 3.0L ENGINE
^ RADIO - ENGINE IGNITION INTERFERENCE (AM OR FM BAND) - VEHICLES WITH 3.0L ENGINE
LIGHT TRUCK:
1992-94 RANGER
This TSB article is being republished in its entirety to include additional parts, e.g., ground strap.
ISSUE:
Engine ignition interference/noise may be heard through the radio AM or FM band. This occurs because:
^ Radio Frequency interference (RFI) from the ignition system to the cluster creates feedback into the radio system
^ Excessive electrical interference is created by the ignition system
ACTION:
Install/Replace the following service parts:
^ An RFI Suppression Audio Cable into the coil, ignition Control Module (ICM), and cluster ignition system and ground the leads
^ The ignition distributor cap
^ Underhood ground strap and body-to-frame ground strap
Refer to the following procedures for service details.
RFI CABLE PROCEDURE
1. Route the RFI Suppression Audio Cable (F47Z-14A411-B) from the ignition coil to the 53-pin bulkhead connector and the ICM as shown in Figure 1.
2. Disconnect the C172 coil connector from the coil.
3. Insert the large square terminal from the RFI Suppression Audio Cable (F47Z-14A411-B) into the C172 connector, Figure 2.
a. Ensure the terminal is fully seated.
b. Reconnect the C172 connector to the coil.
4. Remove the capacitor mounting bolt.
a. Install the ground eyelet between the capacitor bracket and the coil frame.
b. Reinstall the bolt.
c. Ensure there is a good ground and that the eyelet is securely fastened, Figure 2.
5. Route the cable around the engine as shown in Figures 1, 3, 4, 5 and 6.
a. Ensure the cable will not interfere with other component operations.
b. keep away from belts, cables and extreme heat sources such as the exhaust manifold, etc.
6. Disconnect the C105 bulkhead connector located in the LH rear of the engine compartment on the safety wall, Figure 7.
a. Locate Circuit # 11 (T/Y), Figure 8.
b. Remove it from the connector and tape it back to the existing harness.
7. Insert the long thin terminal (round) from the RFI Suppression Audio Cable (F47Z-14A411-B) and insert it into the Circuit # 11 slot of the C105 (53) connector, Figure 7.
a. Ensure it is fully seated.
b. Reinstall the connector.
8. Disconnect ICM Connector C1006, Figure 9.
a. Remove the wire from Pin B (Circuit # 11 T/Y) from the connector.
b. Tape the wire back on the existing harness.
9. Install the small square terminal of the RFI Suppression Audio Cable (F47Z-14A411-B) into the Circuit # 11 slot of Connector C1006, Figure 9.
a. Ensure it is fully seated in the connector.
b. Reinstall the connector on the ICM.
10. Remove the front battery ground to the front radiator support nut, Figure 10.
a. Install the ground cable from the RFI Suppression Audio Cable (F47Z-14A411-B) on the stud and reinstall the nut.
b. Ensure there is a good ground.
11. Check all connections for proper fit and all cables for the proper routing.
DISTRIBUTOR CAP PROCEDURE
1. Refer to the 1992/93 Ranger Service Manual, Section 03-07, for service details.
2. Confirm that the radio interference has been reduced after completing all repairs.
UNDERHOOD GROUND STRAP
1. Verify the interference condition still exists on weak AM stations.
2. Install two (2) ground straps between the hood and cab.
3. Remove the front bolt from the upper hinge (Figure 11) and install one end of the strap to the bolt.
4. Reinstall the bolt and torque to 7-11 N.m (62-97 lb-in).
5. Remove the front bolt from the front quarter panel mount (Figure 11) and install the other end of the strap between the bolt and sheet metal.
6. Repeat this procedure for the other side of the hood.
BODY-TO-FRAME GROUND STRAP
1. Clip one end of the strap to the lip of the frame bolt support (Figure 12).
2. Clip the other end of the strap to the cab pinch weld seam (Figure 12).
3. Repeat this step for the other side of the vehicle.
PART NUMBER PART NAME
F47Z-14A411-B RFI Suppression Audio Cable
F37Z-12106-A Distributor Cap (Motorcraft Part No. DH5O4)
E37Z-14303-AA Ground Strap
D5FZ-19A095-A Ground Strap
OTHER APPLICABLE ARTICLES: NONE
SUPERSEDES: 94-17-10
WARRANTY STATUS: Eligible Under The Provisions Of Bumper To Bumper Warranty Coverage
OPERATION DESCRIPTION TIME
960814A Install Cable Assembly 0.5 Hr.
960814B Replace Distributor Cap 0.4 Hr.
960814C Install Four (4) 0.4 Hr.
Body-To-Frame Straps
DEALER CODING
CONDITION
BASIC PART NO. CODE
12106 56
14A411308
OASIS CODES: 203000, 205000, 207000, 499000, 702000