Grounding of sled

After a tedious and long lasting process (>1 year) I have finally diagnosed and corrected the ground loop noise (ignition whine) in my Miata installation.

What I did, as a matter of a lucky guess, was run a ground wire from the sled (jamming it between the player and the sled) to the cigarette lighter socket.

To my surprise and gratitude the whine went away.

I had tried to ground the sled earlier in the process but sent the ground wire to the grouding point of the player....and that is what was wrong. I can't elexplain the reason why this didnt work, but to a different grounding point it certainely did work!

Also, upon fixing that issue I installed my old Sony cd mp3 player..and grounded that the the same point as the sled AND installed a noise choke between the line outputs of the Sony and the AUX input of the Rio...absolute silence.

The player now sound better as well for there isnt any drain of current that would have gone directly to the amps.

So, lesson learned: perserverance and creativity!

I was on the verge of scrapping the whole rio installation..but now tooling around town very happily!

Thanks again to all who contributed to this install!

Ed

tooling?

2. To drive, as a coach. [Slang, Eng.]

meh

So these's hope for us! Can you explain where you tried both times to ground in a little more detail?

It sounds like your orginal "grounding" point probably wasn't much of a ground, and the lighter socket ground was a better ground. Or the car audio gnomes just fixed things over night in their quest for profit.

Matthew

The ground for the HU is to a bare metal spot in the trunk attached with a screw. I had originally run a ground wire from the back of the sled (attached with a screw as well) to this spot in the trunk...but there was no difference in noise.

I then ran it reom the sled to the lighter socked and the noise disappeared. For the final install I ran it from the screw in the back of the sled to the ground point for the original HU under the dase with a spade lug. The install just didn't like a common ground for the sled and the player (my thoughts that the entire chassis of the car is just one big grounding point has been proven wrong).

Like I said, I then reinstalled my Sony so I can use the tuner and the mp3/cd player when needed.

Prior to fixing the gounding point, the sony would generate noise without the engine running!...grounding the sony to where the sled was grounded reduced it somewhat, but the noise choke, which i really didnt think would work, cancelled ALL of the noise!

Now...I am thinking of installing some rear speakers in the windblock, but that would require that i take the HU out again to access the rear outputs...considering that it tool an hour to securie all of the wifing behind the dash in the first place (remember..it IS a Miata) perhaps I will just split the signal at the amp to the front and rear and use the gains on my 4 channel mtx to balance it out

..and that's that!

I give up! My prior posting notwithstanding my nemisis has is alive and well in the form of ignition whine.....without touching any of the wiring the aforementioned scourge is back in force...even when I run a jumper wire from the sled to a metal ground that I know worked before...nothing happens....Now i have to rip the dash apart again and try to find the source of my angst!

will fill you in as i go along

Ed

Wow, very sorry to hear that.

Perhaps it's just something bad in the amp. Someone else recently posted that they replaced their amp and all the problems went away.

..saw that one..I am using an MTX and an Alpine...both reputable....very strange!

See if unplugging ONE of the amps makes the nose go away.

If so, I'll bet that unplugging EITHER amp, doesn't matter which one, would produce the same result. Ground loops can often happen because of differening ground potentials in a two-amp system.

im thinking a blow torch in a strategic spot will get rid of the noise as well!!!!!

...however..before that..i will give your recommendation a try!

thanks

Don't suppose you can resize your avatar? It's around 50k and much bigger than it needs to be

My noise was caused by a bad amp....

yes..read that...there is certainly a gremlin in my system for this morning..as the system was booting up..i turned on the headlights (with the hi-beams already on) and the unit shut down...then eventually began rebooting again with the ignition whine several times louder than normal..so im thinking:

Should i re-route the hot wire directly to the battery and not to the stock wiring harness?

Skipping the stock harness is seldom a bad idea , both for power and ground...

/Michael

...now I have something to do over the weekend!