[trkpony]

Ok, I took my 66 coupe / 289, which was running perfectly down to the stereo shop to install satellite radio/cd and an alarm. Since then the voltage guage jumps around. Sometimes the car runs rough, other times not. When the headlights come on, the car will die unless you are driving or reving the engine a little. Don't even try using the AC!! This all happens whether the stereo is on or off. I have replaced the voltage regulator. My dash lights don't flicker, just dim when the car dies. My AMP guage always stayed real stable until, I had the schmos put in the stereo. I'm going to have them pull it if I can't figure this out. I just hope they didn't screw anything else up. Any thoughts????

[stlwagon]

Welcome aboard... We'll have more success getting you an answer in here.

[snowboarder7710]

depends on where they got their power from. if they tapped into the wiring at the steering column that may be drawing too much power from them. do you see any new wiring at the battery? if so, try to trace that to either the radio or alarm. if you can, try removing the fuse for the alarm and see what happens...same with the radio...do one at a time that way you can trace which one is causing the power draw.

[The Greek]

If they tapped into the circuit that provides power to the coil, which has a built in resistor to reduce voltage to the coil to a reduced voltage of about 8-9 volts, the radio equipment may still work, but it will reduce the available voltage to the coil. This may be the reason for the engine to act up.

Even if the stereo/electronic equip. is turned off, is all of the system off or is part of the system remaining powered up? You need to check the car's available voltage at the battery when everything is powered up. If you are getting about 13.5 to 14.5 volts, you're OK. If the battery doesn't have enough reserve capacity or the alternator isn't large enough to keep the system at a constant voltage as mentioned above, you will need to upgrade to a higher output charging system.

With what you mention, the capacity of the alternator output seems suspect. A battery with a low reserve capacity (fails to properly stay charged or too small) will add to the problem. Check the system's available voltage at the battery with everything powered up first and go from there.

[Montana's Stang]

Originally Posted by The Greek

If they tapped into the circuit that provides power to the coil, which has a built in resistor to reduce voltage to the coil to a reduced voltage of about 8-9 volts, the radio equipment may still work, but it will reduce the available voltage to the coil. This may be the reason for the engine to act up.

Even if the stereo/electronic equip. is turned off, is all of the system off or is part of the system remaining powered up? You need to check the car's available voltage at the battery when everything is powered up. If you are getting about 13.5 to 14.5 volts, you're OK. If the battery doesn't have enough reserve capacity or the alternator isn't large enough to keep the system at a constant voltage as mentioned above, you will need to upgrade to a higher output charging system.

With what you mention, the capacity of the alternator output seems suspect. A battery with a low reserve capacity (fails to properly stay charged or too small) will add to the problem. Check the system's available voltage at the battery with everything powered up first and go from there.

I agree with Snowboarder and The Greek. I installed stereos for a couple of years and tapping into ANY ignition related circuit is a BIG no-no. Not only will it cause noise in the sound system (if you have background whine or buzz it's a good sign they used an ignition related circuit) it can wreak havoc with the operation of the ignition and other systems.

I have a '68 and in my opinion the only acceptable source for switched power is from the original switched power wire for the radio (I believe its yellow w/ black stripe but don't hold me to that). Since the old radios did not have "power dependent" pre-sets that require constant voltage there is not a constant power wire in the factory radio harness. The best source for constant power is to run a new wire direct to the battery (or "hot" side of the starter relay). The same holds for the main power for amps (be sure to use a sufficient wire gauge for your power draw and make sure it is fused within 6 inches of the battery/relay and route your wiring clear of ignition related wires that could "induct" noise into your system).

You mentioned headlight related problems. In order to get your stereo illumination to work in conjunction with your inst. panel lights they may have tapped into the instrument panel feed (blue w/ red stripe...but again don't hold me to that) and tied it to the stereos illumination wire. This should not normally cause a problem but who knows where or how they may have done it. Another possibility is they tied your stereos Illumination wire into the same switched power source they used for the decks switched power (if your stereo lighting is the same intensity regardless of your parking/headlights being on/off this is what they did).

Remove power to your stereo components (deck, amp, powered cross-overs, etc) one at a time. The easiest way is to remove the fuses that should be in the wire harness of the component. If the problems persist after everything is powered down then I would say they altered your original wiring in some way in the course of doing the install...or you have power capacity problems (as explained by The Greek above) that were not noticed until the additional amperage draw of the stereo was added to the equation.

Hope this helps.