radio engine noise

Well here goes!  I just bought a 98 disco not long ago.  The factory radio was locked out so I figured instead of paying for the unlock code I would put in a new kenwood So I had a hook up for my sirius.  Anyway, bought the adaptor harness, and had everything hooked up by a friend that works at a local sound shop.  We got everything in and there is some crazy noise coming out of the speakers.  So of course we start trying different options to knock out the noise....ground loop isolators, capacitors, grounded the engine to chassis, regrounded alternator, even went as far as running new lines for power and ground directly from battery.  And no luck.  There is a whine when the truck is off but when it is running the noise headache material!  Anyone ever have this problem and get it fixed.  I see alot of posts on here about radio noise but no posts from anyone who has ever fixed the problem.  Everyone cant be driving around with a stock stereo.  Please help!  I think the next step is going to be a good set of plug wires that are insulated well.  and hooking a spare speaker up to the headunit before the signal goes to the amp trying to rule out the amp.

I have had this problem with other cars and aftermarket headunits. It was the plug wires every time.

If plug wires don't do the trick, there is  a capacitor on the back of the alternator that is supposed to cut noise. You might consider replacing it. Some are mounted ouside the back black alt housing, some are mounted just inside of it. If you remove the alt, and the 4 screws that hold on the back plastic cover, you will see it located between the brush holder/regulator assembly and the rectifier (half moon metal object where wires are soldered). It would cost a buck or two from the local alternate shop. I'm rebuilding my alternator right now and the guy from the alt shop said he's never replaced on, they don't go bad very often. But if they did they would lead to a lot of whine.
 
Mark G

Ive been working on the same problem for about a week, did the noise filter for the power, ground, and ignition wires; then the noise filter for the RCA jacks; tried different ground points; nothing helped.  I am most likely going to bypass the factory amps and run wire directly from the deck to the speakers, the metco wiring harness is not a good route for these trucks.

event the best of  headunits bought aftermarket are not going to be able to run that many speakers without an amp and give you the sound quality that the system is capable of.  And you are right there isnt much room for wires.  As for bypassing the factory amp.  did you try to hoop an extra speaker up and determine if the noise was coming form the amp or before the amp

quote:

The factory radio was locked out so I figured instead of paying for the unlock code I would put in a new kenwood

 
I don't get the above remark. I called two dealers in different parts of the country for the radio code and neither tried to charge me.
 
Mark G

quote:

ORIGINAL: greenbayfan

event the best of  headunits bought aftermarket are not going to be able to run that many speakers without an amp and give you the sound quality that the system is capable of.  And you are right there isnt much room for wires.  As for bypassing the factory amp.  did you try to hoop an extra speaker up and determine if the noise was coming form the amp or before the amp

Havent bypassed the factory amps yet, still have them hooked up to my preamp outs on the back of the Alpine.  Ive been busy bouncing back between the water pump/viscous fan clutch and changing the valve cover and oil pan gaskets so the radio is on the back burner til next week.

I dont know.  the local land rover dealer i called told me that they would have to unlock it.  if that is not true and it is something i can do let me know.  But it was my understanding they had to do it and nothing the land rover does is free..........

You should have asked them if they were going to charge you.
On Volvo's if you turn the key "on" but do not start the car and let it sit with the stereo asking you for the code for 30 min it will unlock itself.
Otherwise paying the dealer $20 is cheaper than a new headunit.

i have tried to call the dealer again and of course they arent open on the weekend.  As for the price of the headunit .....i already have it.  the factory land rover radio doesnt have a place to plug in my sirius sat.  The kenwood does.  that is why i want to swap them it out.  is there a place i can get the codes without the dealer.

You're probably running the amp'ed outputs into the pre-amp inputs and causing noise enhancement.  Try running from the pre-amp out on the hideaway to the pre-amp in on the amp.  I had done that at one point and it worked.

i actually got ahold of a different dealer and you guys were right.  They didnt charge me for the code.  Maybe the last guy was blowing smoke up my butt.  Anyway, I have the code for the radio after faxing over a copy of the vehicle registration and drivers license.  So, tomorrow i am going to hook up the factory headunit and see if the noise is still in the radio.

Pretty basic, but I didn't see it mentioned. You should be using resistor spark plugs if you aren't already.