Hey All

I'm have a problem with my CB Radio with noise

When the engine is off and nothing running in the vehicle The SRF Meter
on the radio around 0 on the higher channels like 27-40 and Around 2
and sometime jumps up 3 or 4 on the lower channels 1-26

But when I turn the Key on but don't start the vehicle. The SRF Meter
Jumps to 7 to 9 when the fuel pump is pressurizing the Lines and when
the pump turns off the meter returns to when the everything is off.

When the Engine is Running the SRF Meter is at a constantly around 9
and sometime jumps to the 30+ mark on the meter

The radio is a Midland 79-290

I have try putting Noise filter on the power line of the radio and that didn't work.

 

Check your grounds

 

I Check the grounds and they are fine

 

First unhook your antenna and see if the noise goes away. If it does, you need to filter the noise at its source....Likely the fuel pump. Fords are HORRIBLE at producing noise from the fuel pump. If the noise stays with the antenna disconnected, ots coming through the electrical system and is much easier to cure

 

I unhooked the antenna and the noise is gone. but when rehook the antenna the noise is back

 

Thats what I was afraid of.....There WAS a TSB on 99 and earlier models to cover this problem....I will post it. Look through the TSBs for your model and see if they extended it. The noise must be filtered at its source.
99-12. Publication Date: JUNE 7, 1999
> Article No. 99-12-9
>
> Fuel System - Fuel Pump "Whining"/ Buzzing" Noise
> Comes Through Entertainment Or Two-Way Radio Speaker
>
> Radio - Entertainment Or Two-Way Communication -
> "Whining"/"Buzzing Noise in Speakers Caused By Fuel
> Pump
>
> Noise - "Whining"/Buzzing" - Comes Through Speakers Of
> Entertainment Or Two-Way Radio
> FORD:
>
> 1990-93 TEMPO
> 1990-97 PROBE, THUNDERBIRD
> 1990-99 CROWN VICTORIA, ESCORT, MUSTANG, TAURUS
> 1997-99 CONTOUR
>
> LINCOLN-MERCURY:
>
> 1990-92 MARK VII
> 1990-93 TOPAZ
> 1990-97 COUGAR
> 1990-99 CONTINENTAL, GRAND MARQUIS, SABLE, TOWN CAR
> 1991-99 TRACER
> 1997-98 MARK VIII
> 1997-99 MYSTIQUE
> 1999 COUGAR
>
> LIGHT TRUCK:
>
> 1990 BRONCO II
> 1990-96 BRONCO
> 1990-97 AEROSTAR, F SUPER DUTY, F-250 HD, F-350
> 1990-99 ECONOLINE, F-150, F-250 LD, RANGER
> 1991-99 EXPLORER
> 1993-99 VILLAGER
> 1997-99 EXPEDITION, MOUNTAINEER, WINDSTAR
> 1998-99 NAVIGATOR
> 1999 SUPER DUTY F SERIES
>
> This TSB article is being republished in its entirety
> to include 1997-1999 model year vehicles.
>
> ISSUE:
>
> 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 FLEIBLE FUEL VEHICLES
> (FFVs) OR 1999 RANGER 3.0
>
> 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,
> >.
> a.Cut the wires to the fuel pump 76mm (3") from the
> flange of the fuel pump and discard the wires.
>
> b.Connect the RFI filter connectors to the spade
> terminal on the fuel pump.
>
> c.Cut and solder both the red and black wires of the
> RFI filter to the red and black wires of the flange.
> 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 SPECIFIELD 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.

 

Hey Thanks

Now i just need to find a place in minnesota that will install it for me

 

2 issues.


One is the Fuel pump as indicated in the thread. (there is something on the web somewhere I saw that had an easy fix for this.... I will see if I can find it.)


Second is your antenna it not tuned. Specifically it is too short.


What kind of antenna is it, where is it mounted, what lenght of coax are you using?

 

The Antennas are tuned the swr is around 1.2 to 1.4. the antennas is located be hand the back window and the make of antenna is by firestik. and the Cable is a high grade CB cable and the length of the cable is 18 feet just anuff to make it to where the radio is located

 

Then you are fine as far as SWR. I would double check it with another or an external meter just to be sure.


I think the fuel pump is giving you false "higher" readings.



Does it bounce or is the SWR just higher?



I personolly can not see how a fuel pump could change swr other than false readings.


If you lower the mic gain (on the radio and the mic) does it change?



Edit to add:


I just thought of this.


You say you use 18 feet and it "just reaches" where do you run the cable that it "just reaches"?



Try another cable and just for testing sake just go from radio, out the windo to antenna. Perhaps its your alternator or the spark causing the problems if you go through the engine cab.

 

This would have nothing to do with SWR.....He is taling about the S-meter reading when the noise comes through. RX has basically nothing to do with SWR

 

I argee with Frmboybuck the The swr is not the problem. I can transmit just fine i just can't here what other people are saying becouse the niose is to high.

 

You are right I misread.... My bad.



Let me redeem myself.



Your fix is Here

 

I will try this first it look very easy to do

Thansk

 

That will work, however do not use butt connectors.....SOLDER all wire splices you make. No matter what kind of connectors you use they will corrode and cause problems eventually