Question about Pioneer DEH-P780MP CD Player

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Loud engine noise through speakers

Hi, I'm having a strange problem with my head unit, almost a month after installation I began to hear a very loud engine noise through the speakers. To begin I have it connected to a 4-channel Kicker kx-350.4 and four sets of Phoenix Gold 6.5" component system speakers. Before buying the new head unit I had a Pioneer deh-p8200r and never had that kind of noise with identically the same setup. I checked all the grounds, from the head unit to the amplifier, battery, also installed inline 12V noise filters and nothing happened, I took the head unit out of the dash and turn it on to check if it was some kind of radiation inside the dash but nothing happened. I followed a noise-supression guide from but solved nothing, I connected mi iPod through the RCA cables to my amp and the noise was gone so it isn't my amp nor the rca cables. I decided to install the old head unit back into my car and with it there is not a little bit of noise so I concluded it's a problem with the head unit. One last important thing, the noise is even present I have the key on ACC. I contated Pioneer and the gave me a list of local repair shops but when I call to one of them they told me they woudnt repair it because I dont have the receipt. So I will have to repair it on my own but I just wanted to know if this is a common problem, I've been making installations for almost 4 years and never had this kind of problem. I will appreciate any help you can give me. Thanks

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Re: loud engine noise through speakers

Here we go again. i just had the same problem with my pioneer 1900mp. a little research found something out. with the pioneer units, they have a problem with the rca pre out jacks. they can burn out as soon as a little bit of electricity gets into them. of course i tried everything to diagnose the "engine" noise. but nothing worked, so i tried running speaker wires to the high inputs of my 4 channel amp, and the noise was gone. it's your pre outs, unfortunately. but fortunately for you, if it's still within the warranty period, they will probably work something out with you. pioneer customer service is wonderful. give it a shot.

Posted on May 07, 2008

Re: loud engine noise through speakers

Jadrian - I purchased a DEH-P780MP and have the exact same sound. My suond however increases in pitch throughout the RPM range and is audible when operating the headunit on ACC. I have found this problem to being typical in Checy Sports cars since I can swap this head unit out from my camaro SS into my Mustang Saleen and the sound disappears. The same is true for a swap into my SUV. Never quite figured it out! I think the 12V line from the fusebox or from the battery itself doesn't have "clean" power.

Posted on Oct 08, 2007

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Why would only 5 of 6 speakers work after new head unit car audio install?

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Whining noise @ acceleration?

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Horrible noise coming from subwoofers

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Cold Blooded Stereo

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