Kenwood HU cutting out?

[bmwstephen]

might be a question for Mr. Luke. For my 1990 325is with factory premium speakers, I purchased a KDC BT645U.

A buddy and I tackled the job over the weekend following most of Luke's audio threads. We removed the factory amp and re-looped the audio to all 6 speakers. The unit functions very well for the first 15 or 30 mins of usage but shortly after the sound would either 1) fade away until the sound goes out or 2) the unit would go into "Protect" mode.

For the first problem, if I crank up the volume manually in attempt to counter the fade away effect, the sound would get worse (static and unclear).

For the 2nd problem, the unit is supposed to go into this mode only if a wire is short but the all connections are well insulated and secure (I tested it by rubbing those wires up on the chassis while the HU is playing) and there was no interference during playback when I was trying to stress out the speaker wires.

Additional info:


-318ti/z3 antenna conversion (should I not connect the power control/motor control wire to the HU?)
-speakers are powered by the head unit.
-factory amp is bypassed and wires relooped (did not need to run new wires from HU to speakers)
-problems appear faster if I actually start the car or when its running (possible power draw issue? should I put in a higher fuse?) and takes a while to appear if the key is in position 1

At first after checking all the wires, I suspect that these problems are occuring because the unit itself is overheating. I mean the heat sink behind the unit heats up to untouchable status after a minute of use and I've heard this is the issue with Kenwood units but any input would help.

[bmwstephen]

http://www.crutchfield.com/p_113BT645U/Kenwood-KDC-BT645U.html?tp=5684

[StereoInstaller1]

No...that wiring is wrong.

Since you aren't using the amp, you will use all 8 speaker wires.

Grab that little mess and re-do it.

Somewhere I posted a chart that shows the bypass and shows deck wiring.

Here is the basics: use the 4 pair of twisted wires: red strips and black stripe are positives, so brown wires are negatives (yes, BMW uses black stripes as +)

Now back at the amp, you will use that same 4 twisted pairs (8 wires, 4 twisted pairs) and simply connect them to the 4 pair of speaker wires which will be radically different.

Use your ANT CONT (blue) to the white on the antenna.

[bmwstephen]

yikes, thanks for the input luke. Wish you were local. I think at this point, I'll bring it to a prof. this job is a little too intimidating for me It would probably be best for me just to run new wires to the speakers

[StereoInstaller1]

What I propose is easier.

Find that chart I posted, I forgot to ask for it to be stickied.

You are literally 16 connections from done.

[StereoInstaller1]

BTW: it is highly unlikely that you will find a "pro" anywhere that will do this job properly.

Today things are plug and play, so basically no one gets trained on these cars.

[bmwstephen]

i'll snap pics of the amp rewiring before I get to it as well. I just assume my amp bypass wiring was successful since I was able to get sound to all 6 speakers

[Cabriolet]

to do these cars right, i restring new wire to each speaker. also you need to cut the on dash balancer out of the equ. he was trying to run all 4ch on 2ch out puts like stock. aka BAD idea. he also messed up and left out the power ant.

[StereoInstaller1]

to do these cars right, i restring new wire to each speaker. also you need to cut the on dash balancer out of the equ. he was trying to run all 4ch on 2ch out puts like stock. aka BAD idea. he also messed up and left out the power ant.

Whatever wire you "restring" is nowhere near the quality of BMW wire, just so you know.

Trust me on this, the BMW wire is the shit.

If he can do it as I say, he will have proper connections everywhere, and have the ability to add amplifiers easily and correctly.

[Cabriolet]

i always restring with 10ga copper stranded wire. the stock is 14ga no? which was just under what id prefer.

Whatever wire you "restring" is nowhere near the quality of BMW wire, just so you know.

Trust me on this, the BMW wire is the shit.

If he can do it as I say, he will have proper connections everywhere, and have the ability to add amplifiers easily and correctly.

[StereoInstaller1]

Wait...let me get this straight...you are saying you run 10 gauge wire to your mids and highs?

[bmwstephen]

hope you're still reading this Eric and Luke. Below are pics of the amp bypass my tech did. I assume its correct (I say this because I do get sound to all 4 speakers + 2 tweeters). However, I sense that something is wrong.

[blackhawkimpact]

You should cover those cut wires with electrical tape or something.

[bmwstephen]

You should cover those cut wires with electrical tape or something.

they were covered prior to taking the pics. I removed them to get a better look at what wires were cut and spliced and Luke's comments for the amp bypass wiring before I continue with this project. I assume the wiring back here is correct because as mentioned earlier, I have sound to all 6 speakers

[blackhawkimpact]

Oh, nvm then. You should rewire everything again. I had a similar problem and had to rewire the whole unit.