problem with engine noise through my intercom

[Curtis Guise]

Anyone else have this problem? Scott at PCI told me to make sure the intercom and race radio are all grounded to the same spot but that didn't work. He is prerunning in Baja so I don't know if he will be back with more ideas before I leave so I thought I would ask on here if anyone has dealt with this.

I have the 4-link intercom, the ground wire and the other ground fromt the corner of the box are grounded in the same spot as my race radio. when the race radio is turned off you can only hear a light engine noise when the squelch is turned off or when you talk. Once I turn the race radio on the noise gets pretty bad regardless if you hear the radio through the intercom or not.
To make it worse I wired in my XM radio to the intercom and when that is on the noise is crazy....

I think I might try one of those inline power noise filters.

any other suggestions?

[ShaneR]

I can't remember which one it is but I thought in the instructions to wire your radio and intercom you didn't hook up one of the grounds? Not sure if that is on all the PCI kits or just the older intercoms, maybe someone else has a better memory?

[Socalsixpack]

If you didn't wire one of the grounds, it probably wouldn't work. Are your cables within 2' of any sort of ignition components? I know they advise against that...

[sickrick]

Are you running solid core ignition wires? They cause a lot of radio noise. A bad or shorted wire can cause the same problems.
The alternator can also cause alot of noise, try disconnecting it and see if that helps.

These are the usual culprits with a cb style radio, I don't know if this is the same for a race radio.

[Curtis Guise]

my plug wires are stock Toyota ones for the 3.4 V6, alternator is stock also. I have a fuse block between the seats where everything that isn't stock is wired to. (lights, race radio, intercom...) so all of that is far enough away from ignition wiring. There is a ground wire on the corner of the box of the intercom and Scott said to ground that in the same place as the other ground for the intercom.

I just picked up a couple of noise filters from Fry's so I will try those on the intercom and race radio tomorrow and see if that helps.

[Jerry Zaiden]

Do you have a noise filter on your power wire? Also hook up your power and ground to the battery. Use a good fuse on the power, +, Red, etc... Run the fuse as close to the battery as you can. Make sure you use #10 wire for both powr and ground. This will give you more power.

[DSPracing]

I don't know if this applies to your setup but it's worth a shot. I getting "engine noise" through my car stereo because the power cable touched the RCA cable. Maybe if your power cable is in contact with part of your intercom wiring? Hope this helps...

[racetrash]

like camburg said, straight to battery, and do not connect the ground up on the intercom, it will ground through the radio

[Jack]

With the ground hooked up to both, and the ground that conects them creates a loop like and antenna. Try taking off the ground to the intercom. It dose not take much power so it is safe to ground throught the radio. I have had to do this a few times and never a problem. In some cars it works fine with all the grounds hooked up.

[billymanfroy]

DO NOT ground the intercom if you have it hooked to the radio. The ONLY time you use the intercom ground is if you are not using the radio. The intercom gets its ground through the plug that the hand mic would ordinarily go into.

Oh, and make sure you turn it all the way up and your codog has his plugged in and then plug in yours really slowly. You won't believe the screams!

Good luck, dude!

[Curtis Guise]

so you guys are saying to only hook up the red positive wire? not the ground that is on the plug with that red wire and not the ground that goes to the corner of the intercom box? I think I accidentally disconnected the ground once and the power shut off.

I just tried a noise filter, no luck. I tried taking off the ground to the corner of the box, no luck. Then I tried connecting directly to the battery posts, still NO LUCK..... I even turned the battery switch to the other battery so the one I was connected to wasn't in the system and that didn't help. I also disconnected the plug from the race radio to the intercom.....

what a PITA....

[ShaneR]

so you guys are saying to only hook up the red positive wire? not the ground that is on the plug with that red wire and not the ground that goes to the corner of the intercom box? I think I accidentally disconnected the ground once and the power shut off.

I just tried a noise filter, no luck. I tried taking off the ground to the corner of the box, no luck. Then I tried connecting directly to the battery posts, still NO LUCK..... I even turned the battery switch to the other battery so the one I was connected to wasn't in the system and that didn't help. I also disconnected the plug from the race radio to the intercom.....

what a PITA....

I wish I could help more, we had this same problem and I know it ended up being the ground wires somehow but I just can't remeber the exact cause and fix?

[billymanfroy]

so you guys are saying to only hook up the red positive wire? not the ground that is on the plug with that red wire and not the ground that goes to the corner of the intercom box? I think I accidentally disconnected the ground once and the power shut off.

Here's how we do it, and it's the ONLY way our PCI intercomm works with our roadmaster. I know most of the locos mocos guys run other radios (Icoms & Kenwoods, right?), but I don't know if that matters.

RADIO:
Positive wire straight to the battery.
Negative wire should be straight to the battery, but ours isn't. Still works fine.

INTERCOMM:
Positive wire to the switched side of the emergency cut-off on the A-pillar. When you shut off that switch (or the marine battery selector) the intercomm turns off, but the radio stays on.

The intercomm pigtail screws into the front of the roadmaster where the hand mic goes. This (according to Scott) is where the intercomm gets its power ground. The radio and intercomm must also be chassis grounded. (Not always, but good idea)

DO NOT key the radio without the antenna hooked up, or you can fry the radio. Don't ask me how I know.

Good luck, bub, and call me, One, or Rocket if you can't get it working, I'm sure they all could help you work it out.

Billy

P.S. They always make a little bit of engine buzz, kinda like the incar from rally cars. I'm told changing from resistor to non resistor plugs and/or wires (or vise versa - just get the opposite of what you're running now) can also fix the problem, but some FI cars require one or the other.

[Curtis Guise]

I forgot to say that with the race radio off or disconnected (I have a kenwood that PCI wired to work with the intercom) I have no noise when the intercom is squelched. When you talk or If I turn the squelch so you can always hear something, then you can hear the engine buz (which varies with throttle) but its not to bad.

Then you turn on the radio (connected to the intercom) you can always hear the noise and its louder no matter where the squelch is adjusted to.

The XM does the same as the race radio.

One thing I haven't tried is chassis grounding the race radio. The intercom always has been chassis grounded. I think I have tried every combination of hooking up power to the intercom today.

[coooray619]

i believe a capacitor would take care of your problem... except i cant remember if it needs to be in series with the wire to filter this type of noise or in parallel

[Curtis Guise]

I tried a capacitor and that didn't work. I haven't even messed with it since the 1000. I spent the week in Baja listening to the noise......

[RRose]

my headsets were whining like crazy.... it turned out to be a bad diode in the alt. I narrowed it down by unplugging the alt while the truck was running...... no noise then.

[ntsqd]

Oy! Uplugged it while running? Usually that hurts the Alt. even if it was good b4.

Curtis, it does sound like you've got a diode issue in the Alternator. A 'leaking' diode will let a little AC voltage into the system, which is the noise you're hearing. The frequency of the AC is determined by the speed of alt's shaft which is why it changes with engine speed.

[Curtis Guise]

update.

a month or two ago Mike at Racer X gave me a noise filter to try for my intercom & race radio noise. I wired it in the day before I left for San Felipe last week and it cut down on the noise allot. I can still hear a small whine when only the intercom is on, but when I turn on the race radio it doesn't get any worse. Before this filter it used to get two or three times worse.

its not completely fixed but I can live with it for now.

[5racer]

are the wires run with other wires in a loom or tied up to another loom i run all my radio wires in its own loom on opposite side of car.

[roach]

pci scott had diagnosed my radio interference and came up with a bad microphone in my helmet. dont ask me how or why, but that's what we got. try using different helmet's and see what happens.

[Curtis Guise]

pci scott had diagnosed my radio interference and came up with a bad microphone in my helmet. dont ask me how or why, but that's what we got. try using different helmet's and see what happens.

I have the headsets, no helmet. (mine still isn't wired). But I guess a mic on those could go bad also.

but what kind of interferance did you have? Was it a whine that changes with the RPM's like mine?

[Ryan_P]

I know with car stereo's, if you run a power or ground wire next to an RCA or speaker cable you can get this interference as well. Are you running your headset cable near a power or ground cable? If so, trying routing one or the other a different direction.

-Ryan