bigblockss426

I have a 2001 Grand Cherokee Limited with the oem Infinity system. The Jeep has 102,000 miles on it. Recently, I have been getting feedback in the front dash tweeters and the rear pass door speaker seems to have a "pop" sound in it, only when the engine is running. When the ignition switch is turned to acc, the static is not there. I have changed out the radio with another factory radio, and have replaced the speakers. I think it's the alternator, the static in the front speakers go up as the rpm's increase. I replaced the alternator in May of 2010. The alternator tested good as far as volts/amps. Could it be a diode going?
Thanks
Mike b

jnicewan

Not on the jeep but my dodge truck started doing that, Its a 12v diesel so I could eliminate the ignition and there is basically nothing else electronic to cause RFI. I put my charging system tester on it and it said I had a bad diode. Voltage was ok but low, amps was ok but a little low too, I unplugged my alternator and my radio noise went away Incidently the alternator totally quit the next day.

If you replaced it last May, depending on where you got it most remans come with at least a 12 month warranty. I would think most auto parts stores would have a decent tester that could maybe tell you if the alternator is bad or not. You can also unplug the alternator and start it up and see if the noise goes away.

bigblockss426

Thanks for the advice, unfortunatly, it did not cure the problem. Keep sendin advice please

jnicewan

Well crap, it really sounded like a charging system problem, I would have needed a bad signal to warrant replacement though. Sounds like it might be and ignition problem maybe.

joethepartier

I had an 02 Sonoma that was doing the same thing. I checked everything and could not find an electrical issue. I did replace the factory deck with a pioneer one I had sitting around and it cured it for a while but after six months or so it came back. After talking to an audio shop they pointed me towards the antenna wire.

Found out that it was the wire itself had been rubbed and was causing the interference and killing the stereos at the same time.

I did forget to ask you if it does it only in radio mode or if it also does it in cd mode too.

bigblockss426

It does it in cd mode too.

jnicewan

Check grounds, RFI or EMI can cause interference is grounds are not good. The radio has internal suppresion for these types of interference along with external devices such as...
Radio antenna base ground
Radio receiver chassis ground wire or strap
Engine-to-body ground strap(s)
Exhaust system-to-body and transmission ground strap
Resistor-type spark plugs
Radio suppression-type secondary ignition wiring

Jeepboy99705

My 99 wj did this and I found the wires for the controls behind the stero were shorting out and this was after I put my aftermarket stereo in

WJDave

What year was the new radio you put in? These radios were recalled on the 99-02 models. May just be another bad radio if it was an older one.

Bubbasgoped

Do not use the ground from the wiring harness on the Jeep... Run your own ground for the stereo.

If that doesn't work... Upgrade the grounds off the battery. I have three 4gauge wires off of my battery personally; as well as my alt. Not uncommon to do in the Audio community.

bigblockss426

Well fellows, I just replaced the amp, and it still has the same noise. The real kicker is that when I turn off the engine and switch the ignition switch to accessory, the noise goes away and the radio sounds 100% perfect. FYI, the radio I replaced it with was from a 2001 Sebring, the amp is from a 99 grand Cherokee

Bubbasgoped

Well if you haven't upgraded grounds then I have no more help to give... Good luck!

bigblockss426

Well fellows, I found the problem: the spark plugs!!!!!! I installed E-3 plugs in it a couple months back and I guess they aren't compatable with my Jeep. Thanks all for your advise