Engine whine and ground loop fixes... take two

[Grinder1989 5,000+ posts]

Last night I moved my RCA's to the other side of my car. The noise was reduced so I know that helped. After that I grounded my RCA's to my headunit. Noise was reduced to the point where you could barely here it. These are good ideas for anyone with nosie problems.

 

[wirelessF 10+ year member]

I recently got a new Pioneer HU and the ground loop noise is driving me nuts. By grounding the HU to a metal part of the chassis got rid of the whining noise when in ACC mode. However I still have the alt noise when the engine is running and I'm looking to do it that way, by grounding the RCA's and stuff.

Has anyone tried wrapping their RCAs in alum fil and see if that solves the problem?

 

[uPsDdOWN 10+ year member]

A Very Good Friend of mine took it a step further. Take a min and read through this VERY long post: Interesting.....

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Thank you VERY Much to Rudy and his link to the DIY Mobile Audio Pioneer Head Unit Fix ( I decided to try it on my own.

Following is a list of the steps I took to resolve the noise issue on my 8800 Series deck. Keeping in mind that different Models will have more/less pico fuses, or they may be located in a different place than where I found mine. It is recommended you download the wiring schematic for your stereo and understand the circuitry before even opening the cover on your own radio.

Here is a link to a copy of the Wiring Schematic for this series.

You MUST make sure, with a simple Ohm Meter Test, if the sheild on your unit is grounded or floating. With the power completely disconnected, take your ohm meter and ground one side to the chassis of the HU, or the harness ground--- then place the other end on the rca sheild--- if it measures at or close to zero...it is a grounded sheild, if it measures low then starts climbing to infinity... it is cap coupled. If it gives you a reading of, say 100, 200, etc. Ohms, then you know it is Isolated by a 200 Ohm resistor. Most Pioneer Head Units are floating ground and hence this stupid issue with the fuses POPPING if you arent careful EVERYTIME you unhook and then re-apply the power to your unit... lesson learned I guess!

//content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif ALLWAYS Disconnect the ground cable on your battery before making ANY Connections to ANY electrical component in your vehicle!!!! //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

THE GROUND CABLE ON THE BATTERY SHOULD ALLWAYS BE THE FIRST THING DISCONNECTED AND THE LAST THING RE-CONNECTED WHEN YOU ARE FINISHED CHANGING/WIRING ETC.!!!

This tutorial IN NO WAY is authorized by Pioneer, or the DIY forum and no warranty, gaurantee, or otherwise is implied. If you attempt this task you may risk permanent damage to your head unit. DO NOT attempt if your HU is still under warranty with the manufacturer! This WILL VOID the warranty by the manufacturer.

in other words... DON'T Do It unless you know what you are doing!

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Ok, enough of the crap.....

What you will need:

-A well Lit work area--and magnifier if your eyes are getting as bad as mine! :sad2:

-A Small, low wattage soldering iron (I used a 15W pinpoint solder iron and filed one side flat before heating) Click This text for a Tutorial on proper Electrical Solder Techniques.

- rosin core solder (see link above!)

- A Small Magnetized Philips Screw driver.

- A small flat blade screw driver.

- a 0 (zero) or 1 Ohm, .25 (on quarter--1/4) watt resistor. It is also advised in the DIY forum that it is not necissary to use a resistor... one of the other tips was to use a single strand of copper wire from something like multi strand speaker wire, remote wire, etc. This is what I used--by the time I got into the HU tho, it was too late for me to go and buy a resistor anywhere.

-A small pair of neelde-nose pliers-- I also aquired a pair of medical forceps-- they work AWESOME because the tip is super small and once you clamp it on, you CAN'T drop the wire/resistor/part you are handling.

First..My poor abused car---Gawd it needs SO MUCH work... one step at a time.

Yank her out however it is installed..can't do any damage if its in the dash!

The Non-Do-It-yourselfer has "fixed" most noise problems on Pioneer Headunits by creating a new ground source..or, wrapping the grounds. yep, me too! Then I read this other forum and found out what is actually causing the problem.

so, here is a Picture of the Pre-Amp Out grounds wrapped--- My Style of course! I secured a strand of 14 AWG Stripped copper wire to the center screw first (if you look inside the HU you will find this is what secures these outputs to the chassis of the radio--1st ground) Then I wrapped EACH ground shield and terminated at the screw on the right that is attached directly to the chassis and is also used to secure the bottom half of the "box."

Oh, and I DID try grounding it to the chassis first (instead of the default harness ground) This was the second choice, yess...my DMM proved this (even with the bushing) was a solid ground..the bolt passes clear through and the washer gave a solid foundation.

 

[uPsDdOWN 10+ year member]

Pioneer made it NICE and EASY to get to the circuitry... carefull use your small flat blade scredriver to "POP" these two little pressure buttons out--releasing the top.

from Left to right...

Once the top is removed you are looking at the CD Transport... Pioneer attach's this entire unit with four screws.

Screw 1 and 2 are easy. #3 is easy to get too and can be recovered easily with your needlenose pliers if you drop it...

#4-- here is where you need the magnetized screwdriver! It is buried down at the bottom, even when you pull this assembly out it is VERY Difficult to set it in there for re-assembly--trust me-- magnetize one of your small screwdrivers! You will thank me!

Now, be VERY CAREFUL... the upper cd transport assembly is attached to the bottom Circuit board with a very thin and fragile ribbon cable... if you can gently set it aside, that would be better than pulling it..those tiny ends are a BEAR to get back in!

Now you are to the MEAT of it!

Notice my HU has three outputs... F/R/S-- SO, there are three pre-amp Pico Fuses that need to be checked. I did Not take the board out and turn it over...sorry... the pico fuse just looks like one of those small diodes. NOTICE: that the FU Pico FUse is parallel to the CN circuit. Just another way you know you are looking at the right solder joint.

FU352= Front Output

FU151= Rear Output (I dont use these in my system)

FU351 = Sub Output -- Its hard to see--it is the one next to the coil

After some testing I found that the FU352 Pico fuse is the one (well one of the components) introducing noise into my radio.

So, a strand of copper and...we bypass the blown pico fuse!

(sorry bout the quality (or lack there of in the pic--no matter what I tried I just couldnt get a GOOD pic of the bridged soldered connection)

OR

YOU can actually use a resistor, just make sure no part of the lead shorts agains any other component in the case!

Thank you to "dalinkwent" on the DIYMobileAudio Forum for this picture!

This is a proven Fix and I want to thank the fellow geeks Over at DIY MOBILE AUDIO for the instructions!

 

[AJ²06 5,000+ posts]

OR

YOU can actually use a resistor, just make sure no part of the lead shorts agains any other component in the case!

Thank you to "dalinkwent" on the DIYMobileAudio Forum for this picture!

This is a proven Fix and I want to thank the fellow geeks Over at DIY MOBILE AUDIO for the instructions!

tHATS HARDCORE

 

[CRAZYCORNUTS18 10+ year member]

ok my engine whines like crazy and its really anoyying i made sure that my amp was grounded good, i sanded it down and everything and it still whines what to do next?

 

[uPsDdOWN 10+ year member]

Ok, a few other extremes I have done in the past.... I totally isolated the HU from and ground or power source at the front of the car. HOW?

1)- Depending on how your HU is installed your gonna have to get creative and make sure no part of the HU or the sleeve touches ANY metal in the dash..this includes the rear support bracket... your on your own here.. there are a million differnet ways to do this.

2) - I ran new power wire (8GA--because I'm only using line outs, no amping required at the deck) from the dist block and common ground block in my trunk to the dash. At the dash I split the two power wires, One to the constant (yellow or orange lead depending on make) and one to simple Radio shack 12 volt, normally open relay. Power in, power out.... then use the factory wire from the fuse panel to trip the relay. DO NOT Ground the relay ground to the same place as the HU ground tho! You will defeat the whole purpose.

3)- It cannot be said enough... USE SHEILDED or Twisted pair RCA's for the run to the back and if your head unit doesn't do it, get a line amp and jack up the power to at LEAST 4V before running it to the trunk. Amps, crossover, whatever. the higher the output the less likely you will inherit nose from other sources like computers, harnesses, etc in the car.

4)- It should seem obvious, but if it is alternator whine you are dealing with you Should go right to the source. You may consider replacing the Alternator diode bank (that little circuit board on the back where the removabele panel is.. depending on what kind of alternator you use of course, and also replace and reground the regulator--usually located on the firewall or in newer cars under on of the many plastic boxes under the hood.

DO THE BIG THREE... Ground ground ground... make sure other primary electrical components are properly grounded as well... accessories, aux lites, if the sound only happens when you use the brakes (pops and clicks) then check all the relays in the braking system, when your lights are on? When you roll up/down electric windows...

This kind of troubleshooting is all about isolating the bad ground and replacing it. The reason you get the whine/noise is because something is improperly connected or loose and that "source" is "borrowing" (if you will) from your sound system,....the most obvious way that you Hear it before it appears somewhere else.

There is obviously a LOT more to this... it is just gonna take some work and patience. Start isolating stuff..

 

[spike_e 10+ year member]

i just got a pioneer deh-6800mp and i did the wire around the rcas and it worked!!!!!! i had horrible whine and now i have none!!!!!

 

[synikalt 10+ year member]

I Wrapped it! worked well for me in the end! at first i was still gettin bad engine noise...but idk what i did,i kept checkin wit different rcas...and i had to finally switch my rcas around..cause i have 2-channel split to 2 y-adaptser so i can plug 4 channels into my 4-channel amp...no engine noise now...maybe but barley minimal...u have to really listen cause the sound at idle is louder than engine noise

THIS FIXED IT!

THANX!

 

[rmdl51 10+ year member]

So I'm confused, Will grounding RCA's to HU chassis will blow the fuse or not? I have a Pionner DEH-7700MP with a terrible noise and I don't know how to fix it, even I install ground loop isolators the noise didn't went away. Anybody can tell me for sure if I can try this safe?

 

[jmanpc 5,000+ posts]

yes, its safe. lots of people have done it.

 

[413audio 10+ year member]

do you guys think this would solve a staticy like noise coming from my non amplified speakers only when the subs are on? yes i have a pioneer HU.

 

[79corona 10+ year member]

I just installed a new system. The car was prewired for four speakers. I'm getting static through the speakers, even with an iPod attached. This usually gets worse when volume is increased. I believe my system is pretty well matched. Any ideas?

 

[ace_800 5,000+ posts]

Ok, heres one for you.

Nissan Murano with a HU that cannot be replaced so I have a pac unit(ROEM-NIS2, didn't have to cut or tap wires, plugged into stock HU) and I have had engine noise for the longest. I have check and moved my amp grounds to no availe. Should I use another ground for the hu or just go with the ground loops.

 

[79corona 10+ year member]

Why can't it be replaced?