yo bubonitron,
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Most of this is by FORD:
The vehicle ignition system is a source of radio interference. This high-voltage switching system produces a radio frequency electromagnetic field that radiates at AM, FM and CB frequencies. Although components have been designed into the vehicle to minimize this concern, the noise is more noticeable if the radio is tuned slightly off channel for FM programs. Vehicle electrical accessories and owner add-on accessories may also contribute to radio interference. Furthermore, there are many noise sources that are external to the vehicle. These include power lines, communication systems, ignition systems of other vehicles, neon signs, etc.
Favoring the rear radio speaker in noisy areas will help to reduce noise.
Ignition Noise
The most effective method of evaluating ignition noise is to compare the radio performance with the engine on, versus engine off. If ignition noise is present with engine running:
Missing or Damaged Noise Suppression Components
Noise suppression components may be malfunctioning or missing. Service or replace any missing or damaged components.
CHECK that Ignition Noise Capacitor Suppressor is connected w/no rust between CAP and Coil's "Frame"
Lower Left in pic; shows CAP mounted to Coil's "frame"
&
Pic shows CAP wire to Connector
pics by by sewiv (Sandy)
Check to see that the spark plug wires are the suppressor type and that the spark plugs are the correct resistor type.
If so equipped, check to see that the carbon center insert in distributor cap (12106) is secure.
NOTE: Silicone grease must not be removed from vehicles equipped with electronic engine controls (EEC-IV).
If so equipped, check distributor cap and rotor electrodes for silicone grease, as this may cause ignition noise on FM. This noise is characterized by a "motor boat" type sound on weak to moderate strength stations. The noise can only be eliminated by replacing the distributor cap and distributor rotor (12200) with a cap and rotor that do not have grease.
Missing or Poor Grounds
Check bond strap grounding effectiveness by wedging a large file between metal parts to ensure proper ground, such as between the tail pipe and body, or between the fender and frame, while the radio chassis is playing and the engine is running. Listen for a decrease in the objectionable radio noise. If a reduction in radio noise is noted, first try tightening body and exhaust system clamps and brackets. Then, if necessary, install a new bond strap between the two metal parts to ensure proper ground.
Sound Distortion, Premium Sound
Sound distortion can be attributed to any of three components: the radio amplifier (18B849), the radio chassis, or the radio amplifier wiring (19B113) that connects the radio amplifier to the radio chassis. If any of these components is damaged, sound quality will be distorted. The speakers will also cause distortion if any of them are grounded (CDR only). Refer to the Symptom Chart in this section for diagnosis and testing procedures
or;
Fuel Pump Noise in Speakers TSB 02-16-4 & TSB 01-7-3; TSB 99-12-9, rev. for 90-96; "...This TSB article is being republished in its entirety to include 1997-1999 model year vehicles..."
Source: by Ford
see entire TSB w/Figures @
http://www.performanceprobe.com/misc/tsb.php?article=99-12-09
A "whining"/"buzzing" noise in the speakers of the entertainment radio or two-way radio on vehicles with an in-tank electric fuel pump may be caused by electrical noise from the fuel pump.
ACTION Install an electronic noise Radio Frequency Interference (RFI) filter (F1PZ-18B925-A) on the fuel pump inside the fuel tank. Refer to the following Test Procedure to confirm that the concern exists, then refer to the Service Procedure for repair details.
NOTE: SOME LIGHT TRUCKS REQUIRE ONE (1) RFI FILTER FOR EACH IN-TANK ELECTRIC FUEL PUMP ON MULTI-TANK VEHICLES.
NOTE: THIS TSB DOES NOT INCLUDE TAURUS FLEXIBLE FUEL VEHICLES (FFVs) OR 1999 RANGER 3.0L FFVs.
Test Procedure
Fuel pump radio noise is relatively constant and changes only slightly with vehicle speed. If the frequency of the noise varies or the noise comes and goes with the vehicle speed, then it is not the fuel pump and this fix will not be effective. The following procedure will help determine if the fuel pump is the cause of the radio noise:
Turn on the radio before the key is turned on (assuming the radio will operate without the ignition key - you may need to put the ignition key in the Accessory position).
Turn the ignition key to the Run position (do not start the engine).
The fuel pump should run for about 1 second with the key in the Run position with the engine not running. Listen for noise in the radio. If noise is present while the pump is running and stops when the pump stops, then the noise is being generated by the pump and this procedure should help.
Service Procedure
Remove the fuel pump sender assembly from the fuel tank. Refer to the appropriate Service Manual, Section 24-35 for cars/light trucks and Section 10-01 for compact trucks, for removal procedure.
On vehicles without a fuel delivery module, remove the negative and positive connectors from the fuel pump, Figure 1.
Cut the wires to the fuel pump 76mm (3") from the ****** of the fuel pump and discard the wires.
Connect the RFI filter connectors to the spade terminal on the fuel pump.
Cut and solder both the red and black wires of the RFI filter to the red and black wires of the ******. Use Heat Shrink Tubing (F5AZ-14A099-AA) over the solder connections.
NOTE:
HEAT SHRINK TUBING MUST BE USED OVER ALL SOLDERED CONNECTIONS MADE PRIOR TO THIS TSB. USE SUFFICIENT TUBING (ABOUT 50mm (2")) OF THE SPECIFIED TYPE TO ENTIRELY COVER EACH SOLDERED CONNECTION AND SHRINK APPROPRIATELY TO PREVENT EXPOSURE OF THE CONNECTIONS.
NOTE:
FOR SOME VEHICLES WITH EXTREMELY LONG FUEL PUMP GROUND WIRE CIRCUITS, IT MAY BE NECESSARY TO SHORTEN THE GROUND WIRE TO A POINT CLOSE TO THE FUEL TANK. IF THE GROUND IS MOVED, BE SURE IT IS SECURE AND PROTECTED FROM CORROSION SINCE IT IS THE OPERATING GROUND FOR THE PUMP. CHECK SERVICE LITERATURE (EVTM, ETC.) FOR GROUND LOCATIONS.
WARNING:
ALL SOLDERING AND HEAT SHRINKING MUST BE COMPLETED AWAY FROM THE FUEL TANK AREA. USE A SOLDERING IRON ONLY FOR SOLDERING AND HEAT GUN ONLY FOR APPLYING SHRINK TUBING.
On light trucks and compact trucks with a fuel delivery module, cut the fuel pump wires to the fuel delivery module 50mm (2") from the ****** and discard the wires, Figure
Cut the connectors from the RFI filter and solder wires to the fuel delivery module (red to red and black to black). Use heat shrink tubing over solder connections.
Solder wires from the RFI filter to the ****** wires (red to red and black to black). Use heat shrink tubing over soldered connections.
NOTE:
HEAT SHRINK TUBING MUST BE USED OVER ALL SOLDERED CONNECTIONS MADE PRIOR TO THIS TSB. USE SUFFICIENT TUBING (ABOUT 50mm (2")) OF THE SPECIFIED TYPE TO ENTIRELY COVER EACH SOLDERED CONNECTION AND SHRINK APPROPRIATELY TO PREVENT EXPOSURE OF THE CONNECTIONS.
NOTE:
FOR SOME VEHICLES WITH EXTREMELY LONG FUEL PUMP GROUND WIRE CIRCUITS, IT MAY BE NECESSARY TO SHORTEN THE GROUND WIRE TO A POINT CLOSE TO THE FUEL TANK. IF THE GROUND IS MOVED, BE SURE IT IS SECURE AND PROTECTED FROM CORROSION SINCE IT IS THE OPERATING GROUND FOR THE PUMP. CHECK SERVICE LITERATURE (EVTM, ETC.) FOR GROUND LOCATIONS.
WARNING:
ALL SOLDERING AND HEAT SHRINKING MUST BE COMPLETED AWAY FROM THE FUEL TANK AREA. USE A SOLDERING IRON ONLY FOR SOLDERING AND HEAT GUN ONLY FOR APPLYING SHRINK TUBING.
Secure the RFI filter to the fuel pump and sender assembly with a Bundling Strap (95873-S) to prevent rattling in the tank, Figure 1 and Figure 2.
Reinstall the fuel pump sender assembly into the fuel tank.
CAUTION:
INSTALL NEW GASKETS WHEN REINSTALLING SENDER TO PREVENT LEAKS. REFER TO THE PARTS CATALOG FOR PROPER APPLICATIONS.
Check the appropriate Electrical and Vacuum Troubleshooting Manual (EVTM) (or other service literature) for the location of the fuel pump ground. If ground is more than 0.9m (3') from the tank, cut wire and ground fuel pump end within 0.9m (3') of the tank to prevent ground wire from acting as an antenna. Be sure ground is secure and protected from corrosion since it is the operating ground for the fuel pump.
Install the fuel tank in the vehicle as outlined in the appropriate Service or Workshop Manual.
PART NUMBER PART NAME
F1PZ-18B925-A Radio Frequency Interference (RFI) Filter
95873-S Bundling Strap
F5AZ-14A099-AA Heat Shrink Tubing
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Next is Crutchfield's Noise Suppression Guide
http://www.crutchfield.com/S-XcV81qF1lyu/learn/learningcenter/car/noise_suppressors_installation_guide.html
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GL!
