Anyone else have an aftermarket stereo with amp(s)?

I know, I know, it’s complete sacrilege to even play music while driving one of these divine V12 musical instruments. However, I love music, especially on longer trips, and I love nice audio gear, even if I can’t always hear it with the windows down and above 4000rpm. My 550 came with a big trade show system (possibly early 2000s CES) that I have been slowly dismantling (if someone offers you a show car, ask for a steep discount). As I have been correcting many of the install faux pas, one thing I have noticed is how the 4ga. 12v wire feeding the amps in the trunk is sourced from the main bus bar in the electronics area in the right passenger footwell (part #6 on this diagram) instead of getting its own dedicated feed from the battery. This bus bar is also what feeds the fuse/relay board, which feeds all electronics components of the car, including both ECUs.

Last year I lost my right ECU to a toasted power supply and some failed caps. When Specialized ECU Repair fixed it, they said it was something these Bosch ECUs are known to do with age. Fast forward to last night, it was the first time I had powered the stereo since the failure last year because I was afraid it would happen again. And the fear was probably real, because I am 99% sure I lost the left ECU last night after a very spirited 90 minute cruise while blasting my favorite driving tunes. This morning the car would not allow me to lock it after unlocking it to retrieve something, and now I am getting wild errors like empty gas tank (it’s over half full), suspension fault, FCS fault, a P0103 code (MAF signal error which can signify an ECU failure), and a P0600 code which is a can bus connection error=both ECUs are unable to talk, and the engine sputters and dies when starting (same error as last year). Additionally, the information LED square in the instrument panel is flickering, even when not cranking. After poking around it today and giving it some deep thought, I am thinking this stereo configuration may be to blame because it is pulling power from a source that was not designed to support the additional load, potentially causing a voltage drop outside of the ECU power supply’s minimum safe operating range, and frying it. Sadly I cannot prove this theory with a voltmeter because the car won’t stay running for more than a few seconds. But I want to figure this out because these $1000 ECU repairs are starting to add up, and I would be happier putting the money in the rear tire fund instead.

So for those of you with amps installed in your cars, are they being fed directly from the battery? Anyone with a separate battery and isolator? I might go that route for ultimate peace of mind, assuming the voltage starvation theory is right. Thanks!

 

Thanks! Cool looking amp, what brand is that?

 

Nice! How do you like it?

And one more quick question, where is your power wire routed through the firewall?

 

Awesome, thank you.

If you don’t need tweeters, these are worth a try using 5x7 to 6 1/2” adapters:

https://www.parts-express.com/tang-band-w6-1139sif-6-1-2-paper-cone-subwoofer-speaker--264-919

I have the 12” version of this woofer in my office, and it sounds incredible (I actually prefer it over the massive servo Rythmik FV-15HP in our HT system). Apparently the balanced drive motor is ahead of its time, similar to what XBL and XBL^2 did for the industry 10 and 20 years ago:
https://www.parts-express.com/wavecor-sw168wa01-6-1-2-balanced-drive-paper-cone-subwoofer-4-ohm--298-1052

There are a few high end car woofers from Focal and others, but they are 5-10x the price for similar performance. Hope this helps.

 

And I just looked up your amp, very cool that it has a built in DSP and accepts an optical input. Nice small dimensions too.

 

Awesome, thank you! Is it an OEM pass through, or was it added for the install?

Bummer, I did not realize how shallow the rears are from the factory. Do you remember what the actual depth is?

My rear shelf was modified by the original installers so that those holes are open to the trunk to hear the subwoofer more clearly, so they created infinite depth, but it probably took some permanent changes to make it work.

 

Awesome, that is great to hear. Thank you!

 

The power cable was attached to the right stud of the bus bar in the photos below.
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Yeah I’ve been installing stuff for 20 years and I have never seen someone do this. I should have caught it when I replaced the relays on the fuse board, but I was new to the car and thought the bus bar was aftermarket. It was sometimes dropping voltage to 9v, really low. ECU Doctors started testing the ECUs today so we will know very soon if my theory is correct. NVX just released a new micro processor controlled battery isolator that allows a second battery to charge from the alternator, but then cuts it off if the car’s voltage drops below 12.7v. I purchased a Stinger PCC680 battery to mount in the trunk to take as much load off of the car electronics as possible, and enough OFC 4ga. wire to go directly to the battery. Hopefully these solutions will prevent any issues again in the future. Thanks again for your help.

I’ll take pictures of the rear shelf tomorrow.

 

gabf1 that is a killer setup! Great gear choices, love it.