Anyone have both a CB radio and pedal commander installed? - Weird interference

[geofox784]

I just finished installing my cb radio, a Midland 75-822. Not long after installing it I noticed that when parked or at idle the rpm would jump about 1500 rpm when I key up the radio. When in drive it would also have the effect of acting like I was pressing the gas when I was not, but the actual effect on driving was very small.

I then noticed that with the engine off, but the key set to ignition on, I could actually hear the throttle pop back and forth when I key up the radio. I then checked the throttle position sensor with my scanguage and found it at 17 normally, jumping to 21 when the cb was keyed up. I unplugged the pedal commander and found that the problem went away. It appears the the cb radio is causing interference with the pedal commander. It's not enough of a problem to be a "problem" unless extended use is going to damage something. Anyone else experience this, or have both a cb installed and pedal commander and not have the problem?

 

[powells85]

Is the pedal commander mounted near your antenna coax? Maybe add a ferrite bead on the pedal commander cable. Where are you pulling power for your CB? What about the ground?

I'm running a quad band amateur radio, 10 meter, 6 meter, 2 meter, 440, and haven't had any electrical issues. Transceiver mounted under my passenger seat, coax under the door sill, into the engine bay and antenna mount is a lip mount on my hood. Power is run from a relay and to the battery.

 

[geofox784]

Fixed it

I did some googling and found a few others, specifically jeeps, that had the same problem.

I tried adding a ferrite bead to the pedal commander line, no joy. Then I tried adding a choke to the ground line of the radio, no joy. Finally I changed the ground of the radio from my stock 12V jack ground to the steel at the bottom of the transfer case shifter. That fixed the problem completely.

 

[GreenMountainOwl]

Without getting too technical...your CB may have the modulation limiter clipped, which would greatly increase out-of-band harmonics, some of which could interfere with systems in the vehicle, or even other nearby devices.

I had a sweet 91 K5 Blazer when I was heavily into CB back in the 90s-- since then I've become a licensed amateur. Had an amplifier in there and a radio with a clipped limiter. It somehow affected the fuel pump whenever I keyed up with the amp. And, amusingly, I could talk through any nearby speakers as well. That lasted about two months before I wised up and took care of the problem.

 

[4runnercpa]

I did some googling and found a few others, specifically jeeps, that had the same problem.

I tried adding a ferrite bead to the pedal commander line, no joy. Then I tried adding a choke to the ground line of the radio, no joy. Finally I changed the ground of the radio from my stock 12V jack ground to the steel at the bottom of the transfer case shifter. That fixed the problem completely.

Hello.

I came across this thread because I'm having the exact same issue. I have recently installed the Uniden Pro520XL on my 5th Gen 4Runner and every time initiate the radio to talk, the car revs up and less so if I'm in gear. Right now, I have it powered through the cigarette lighter.

I see that you solved the problem by moving the ground wire. Do you have have any suggestions for fixing this problem when I have it powered through the cigarette ligther?

Any input would be much appreciated.
Thanks.

 

[geofox784]

Hello.

I came across this thread because I'm having the exact same issue. I have recently installed the Uniden Pro520XL on my 5th Gen 4Runner and every time initiate the radio to talk, the car revs up and less so if I'm in gear. Right now, I have it powered through the cigarette lighter.

I see that you solved the problem by moving the ground wire. Do you have have any suggestions for fixing this problem when I have it powered through the cigarette ligther?

Any input would be much appreciated.
Thanks.

The problem with running it through the cigarette lighters is the cigarette lighter ground goes through the wiring harness built through the car and creates RF interference havoc. You need to find a way to get the ground from the cigarette lighter to get to the car frame as quickly as possible. If you are using the cigarette lighter just below the AC controls then it should be fairly easy to get behind the cigarette lighter, cut the ground, connect it to some new wire, and then run that wire straight to the same ground location I used. You will just need to remove the AC controls, the plastic tray that the cigarette lighter is in, and the shifting trim. All easier than it sounds.