Weird problems after head unit install, am at wits end.

[jbd99eride]

Ok, first post here and I hope somebody can help. This is a long read but I felt I needed to be detailed.

I recently acquired a 91 325i that was pretty mint.

The PO had a stereo intalled in '05-
OEM premiun tape head unit--> speaker level to line level converter in the trunk(factory amp bypassed) --->Kicker KX700.5 5ch amp---> factory speaker wires to some MB quart comps in front/coax in rear and a sub. The install shop did a great job. I have no complaints there, it all worked perfectly. They did run new wires from the MB x-overs to the factory tweeter wires at the kicks and spliced in there (not sure if this will relate to the current issue)

Fast forward.
3 days ago I purchased and installed (following the sticky on amp bypass to get dash color codes) a new Pioneer DEH-80PRS. This is when it all went downhill. FWIW the head is being run in 3way active mode. No rear speakers, just comps up front sub in the back.

I ran the RCA's (3 pr) down the drivers side. I used all the correct wiring in the dash for 12v constant/switched/ground/illumination as per the sticky.

The problems are-

1. With the key in the on or acc position I get a pop through the speakers when pressing the brake pedal, hazards, blinker, basically when any light switch is used. Including the interior map lights.
2. With the engine running I get the above pop as well as a low level (volume wise) buzz. It is not alternator whine, I had that too but isolated the rca cables and got rid of it. (previously were ran down pass side, Big no no.)

These issues are independent of source or volume.

I have been pulling my hair out trying to figure this out.

So far I have-

1. Tried grounding the head unit to several different chassis points.
2. Tried grounding the head unit to the amp/batt/both.
3. Tried Grounding the rca's.
4. Disconnected the power antenna and its grounds.
5. Connected 12v constant and switched together
6. Connected head unit directly to battery
7. Grounded head unit to power antenna

I have not tried but will try-

1. Connect iPod directly to amp.
2. Connect speaker to head unit to bypass amp
3. Remove amp from seatback sheetmetal. ( I DID check for continuity with a multimeter between the amps chassis and ground and it was isolated. I do not believe that the amps chassis is grounded to the car in any way)


I have done many car audio installs over the years and have never had this kind of strange trouble, which is why I am posting here.

ANY help is certainly appreciated at this point.

Thanks,
Justin

[jbd99eride]

Update-

1. Connected iPod to amp directly--> No noise, no pop
2. Connected a speaker directly to headunis internal amp-->
No noise, no pop
3. Ran a different (Audioquest-all I had around that was long enough and it is a non sheilded cable) RCA between head and amp outside of car-->
No noise, no pop

I'm wondering if these so called "high end" Focal interconnects are junk and causing problems. Interestingly enough when I ran the same Audioquest cables before when I had alternator whine, I still got whine but to a lesser degree. Odd

Any Thoughts besides these Focal cables being the problem?

[dwvw]

Pioneers are actually pretty well known for having this noise. The usual fix is grounding the outer shield of the RCA's to the Pioneer deck ground. Is that what you did when you did number 3?

[jbd99eride]

Pioneers are actually pretty well known for having this noise. The usual fix is grounding the outer shield of the RCA's to the Pioneer deck ground. Is that what you did when you did number 3?

Yes, that is what was done when I tried grounding the RCA's in #3
That actually made the noise worse.
I was under the beleif that that appled more to the older Pioneers from the early 2000's. I have an older 880prs in a different car that had known issues with the pico fuse blowing and that was one work around.

Thanks for the response.

I am going to try different RCA's run through the passenger side and see if that takes care of it. I guess I'm wondering if the general consens would be that the RCA's are causing all of this BS or if it could still be a problem elsewhere.

Any recommendations on a good quality rca? (I'm sure this has been debated)

[jbd99eride]

Swapped amps with no change. Tried grounding the amp to the batt with no change.

I read in another post someone mentioned putting a capacitor in the brake circuit to combat "brake pop". Is this a bandaid or is there really no way around this issue? I fthat is the only solution where does said capacitor actually go. Im guessing her, but, if a capacitor is used, does that mean that some minute amount of + voltage is getting to ground and the cap is helping to absorb that somehow?

[AndrewBird]

Do your brake lights still work?

Sounds to me like something is wired wrong. Maybe the illumination wire hooked to constant/switched power?

[jbd99eride]

All the lights in the car are fully functional as well as the gauges. I was wondering the same thing but wouldny having those wires switched mean one of two things?- if ILL was hooked to switched power the radio wouldn't come on at all until lights were turned on? I guess the same would be true for if I'LL was Connected to constant on the head (yellow).

I'm pretty sure the illumination wire in the dash only gets 12v when the headlight/parking light switch is pulled. I did verify the dash wires voltage operation with a meter before connecting the head unit.

[Gregs///M]

Run the signal wires down the drivers side. Power down the passenger side. The OEM battery cable runs down the passenger side and can induce noise into your RCA.

Sounds like you already narrowed down the problem to the Focal RCA's. Might be defective. Run the different RCA's down the drivers and see if problem persists.

[jbd99eride]

Right, That's how it is all currently run.

I will be trying a few more things tonight including different RCA's and will report back.

[dwvw]

If you want to eliminate everything up stream from the amp as the culprit, make some shorting plugs. Grab a cheap set of RCA's and just connect the ground to the center pin of the RCA (outer shield to inner wire), that will present a dead short to the amps inputs, which does not harm the amp, but it should be dead silent for noise with these plugged in. If the noise goes away, the problem is at the RCA's or earlier in the signal chain. If the noise stays, it's at the amp or later in the chain. I know that moving the signal wires can sometimes help, but since the entire chassis of the car is a ground plane, and you can't truly move the RCA's away from the chassis, it's really a last ditch effort.

[jbd99eride]

Yeah, intersting idea with the shorting plugs, I actually have some so may try that next.

Heres what happened last night-

Connected new RCA's from the trunk , outside the car , in the drivers side to the head. NO NOISE AT ALL. yay.

Proceeded to pull out the Focal RCA's assuming they were poorly "triple sheilded" .

Ran the new RCA's down the same path as OEM stereo wiring down the drivers side to the trunk through the grommet in the back seat. Loosly tucking them where they would finally rest.
Ran the RCA's in the trunk next to the power wires and speaker wires (for about 2 feet) as they would be when everything is neatly tucked away and finalized.
TESTED! NO NOISE, NO POP, NADA. I'm thrilled at this point.

Tuck the wires connect everything up, tidy up, all is looking good, I'm fianlly feeling like this is the end. NOPE!!!

Fire it up and THERE'S THE BUZZ AND THE LIGHT POP. WTF!?!?! The only difference was actually tucking the wires finally. And, only a little more than when I did the test with no noise.

1. Is it likely that bundling up the extra 8 feet or so or RCA cables along with the little bit of excess speaker cable with the factory harness in the driver rear shock tower area could actually be inducing noise somehow??
2. Is it likely that something in the back seat area is causing this? Fuel pump wiring, etc?

I refuse to use those stupid RCA noise suppressors, that isn't a solution.

There has to be a solution here. I cant imagine I am alone in a problem like this, but maybe so..

I appreciate the suggestions so far, for sure. Keep em coming.....

Thanks,
Justin

[dkbmxer002]

Are you checking all your wiring with multimeter? You said you get no pop when I pod is used... Have you checked to make sure it isn't the antenna?

[jbd99eride]

No pop with ipod was when it was connected directly to the amp bypassing the head unit as well as RCA's. I was trying to see if it was coming from the amp or deck. I also got no pop when connecting a speaker directly to the head unit and using its internal amp. Which is what keeps me thinking its the rca's

When you ask whether I checked with a meter, I'm not exactly sure what you are asking. There are a lot of wires in there. Yes I verified continuity in the RCA's and speaker wires. No speaker wires are shorted or grounding. All the dash wires have been verified to be correct in terms or 12v constant, ground, illum, etc.

I disconnected the power antenna several ways which yielded no difference. I also tried grounding it different ways and places and even tried grounding it to the amp/head/both.

Interesting side note- With the power antenna connected, if I disconnect the ground from the head unit,the head unit stays powered on. Why? because the antenna mast is grounded to chassis and the antenna connection on the head is also grounded to the head unit. I thought this may be the issue but the aforementioned tests proved otherwise.

I still believe that the RCA's are picking up noise somewhere along the path. I'm just not sure where. I"m going to try isolating them in sections and see if that turns anything up.

[dkbmxer002]

Have you ran a set of rca's completely out side the car from head unit to amp to determine if they are causing noise? Also the antenna working as a ground is typical.


And test with a multimeter I just mean you didn't only go by the wiring list in the how to.

[StereoInstaller1]

Pretty obvious to me, that deck is known to be a turd. Try another deck, I bet all the issues go away.