'93 Ford F150 XLT

Hello everyone. Alright, I have a Cobra 40 Ch CB with a Wilson Roof Mount Antenna on my 1993 Ford F150 XLT 5.0L 4x4 E40D tranny and it has duel gas tanks. Now, My CB is just fine when my truck is shut off. I get clear reception. But, once I start my truck, I get a constant whine through the CB and when i rev or drive, the whine pitch goes up or down with the engine revs or speed. Also, the worse whine is when I'm on my front tank, when I switch to the back tank, it is a little more subtle, but still there. I did some internet research and came up with calling the Ford Dealer and asking for part # F1PZ18B925A which should be a fuel pump RFI noise filter? I also heard they don't work as well as they say they do. So, another option I found was Feed Through Noise Filters, but I'm not sure what they are, what they do, or how they hook up. Also, I'm not sure if they'd be any better then the Ford Part. My last option I found was a snap on ferrite core, just put a couple of them on the fuel pump leads outside the tank. I'm not sure which of these to go with. In my opinion I would like to go with the Ford one because well, it's a Ford part it should work, but from what I heard, I shouldn't be so sure. Does anybody have any opinions or any help for me. Thanks soo much ahead of time everyone! Have a good one.

wde3477

Perhaps try a generic noise suppressor, either tied into your CB or your alternator. Make sure your grounds are good also.

10man

I agree, GROUNDS being the most important on a CB radio. Run your radio ground straight to the frame. Grind or sand the spot where you bolt it and after bolting paint over it. O yeah, and don't run a flimsy 12 to 16 guage wire for the ground. Use no smaller than 8 guage.

mitchalvin

You could also wrap the power wire around a magnet a couple of times, this is a simple form of rfi filter.

bjafeman

Typically noise filters (even the really good ones) are a band-aid over bullet hole approach to a problem. Chances are you've got a crossed wire somewhere. Like these guys said, check your ground. Make sure it's got a good connection, not just randomly tied in to a wire that shows up as a ground when you're probing around. I've seen home wiring jobs that tied in to speakers for either power or ground. Tragic. Also, make sure that your antenna wire isn't being pinched against metal somewhere like a door jamb or window sill.

When I'm troubleshooting alternator noise (that's what the whine is) I sometimes use a set of jumper cables to run power straight from the battery to the cab - truck parked and running. This requires a little caution but is a good way to see if the power source itself is putting out too much noise. If you still get the whine with a straight shot to the battery then you may benefit from an inline supressor/filter.

Also, because this noise is radio frequency noise (RF) CB's are sort of succeptible to it...since they're RF receivers and transmitters. I'm assuming that these noises are showing up regardless of your squelch setting. Just about any CB will pick up RF interference with the squelch all the way down. A crossed wire, however won't be affected by squelch settings at all and will pick up interference regardless.

zippy

http://97vette.com/sporttrac/rfi_fix/rfi_fix.html

ford_tough_5L

what i got was an A/C adapter to plug from the cb to the "cig lighter" port. i don't get any whine from my cb at all.

94Bronc

i wired mine to the battery with an inline fuse no issues

matthew.adelman

the easiest thing to do is check and make sure you didnt use the fuse that the fuel pump is wired to to wire your cb radio. i had a buddy with a jetta wire an amp to the alternator thinking he would get more reliable power, he ended up just causing the speakers to produce a buzzing sound that gets louder the faster he revs the engine. if you there are two things pulling power from the same source the one that pulls the most current will cause the other to suffer, in your case it makes a buzzing noise. capacitors are used in a wide variety of commercial application for RF (radio frequency) interference. make sure it is intended for use as an RF suppressor and wire it in series (one wire to ground, the other to the power source)