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Discussion Starter · #1 ·
With my stereo's new found power, I'm getting voltage drops. The problem is when I park and shut the car off then put the windows up or down, the audio cuts. It happens instantly once the windows stop and I don't let off the buttons right away. Doesn't happen with the car running and the voltage stays at 14.4-14.6. According to the diagnostic menu in the DIC, the voltage drops from 12.2 to 11.9 when I do this with the car off.

It's probably time to upgrade my grounds. I've made some short cables for the chassis-to-battery and the engine-to-chassis grounds but I'm not too confident in them. I've got plenty of welding cable left so I might get some new lugs and solder them.
 

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What condition is your battery in? I'm usually around 12.6v with the engine off and nothing I do will pull it down below 12v.
 

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If this means you've added some big amp that requires a stiff amount of watts being sucked out of your battery, maybe it has some internal protection built into it. Like if it senses a voltage drop that falls below a certain threshold point, Its told to shutdown for self protection.
Maybe you could parallel a friends battery (without any alternator assisting it) to your power and ground connections in the engine compartment, and perform that shutdown test. If the added amp supply coupled to your battery (all at the 12 to 12.5 volt level) allows your radio to continue to operate as you know it should, it could indicate that *your* battery is a little on the gimpy side when loaded down with a high power audio blasting away *along* with the window motors in a sort of loaded/stalled out condition.
 

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Discussion Starter · #4 ·
With just the ignition on and the diagnostic menu up, it's at 12.2-12.3 volts. The charge % reads anywhere from 81-87%. If I turn the radio on it's more towards 12.2v. Soon as I hit the windows, it drops to 11.9.

It does seem like it goes into some sort of protection below 12v. I just wasn't sure if it was the amp going into protection or the car. The windows keep rolling down when the amp shuts off. I'll see if I can connect someone else's battery up.


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You should load test your battery. If you don't have a tester, they will do it at Autozone or Advanced for you. How many Amps does your new amp pull? It shouldn't draw much current at low volume.


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You should load test your battery. If you don't have a tester, they will do it at Autozone or Advanced for you.


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11.9v shouldn't be low enough to make an amp go into protection. Recheck your power and ground connections. I'd bet where your grounding the amp isn't making a good connection or the ground is weak there.
 

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Discussion Starter · #8 ·
It doesn't seem like the amp goes into protection. According to the manual, a high voltage situation or a short will throw it into protection and it shows a red light where it's usually blue. What happens here is mine just shuts off. I found not only does it happen when I drop the windows without the engine running, but also if I crank it without the engine running.

I'll experiment with the ground location and quality for amp. Maybe get my battery load tested. It's 4 years old. And it sat around most of the first year of its life. It is a little slow to crank some mornings.


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Check your ground at the amp like you are planning to do. Make sure that you have scraped or ground away the paint to a bright metal finish, and make sure it is tight, and not up on the side panels or the trunk lid or the rear deck. Netfly is right, it shouldn't go into protect or shut down at 11.9. What kind of amp do you have? How big of wire? Can you post a picture of your current ground, and battery connections? Where is your remote wire ran from? Do you have a multimeter you can do some measurements for me by chance?
 

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Discussion Starter · #10 ·
I can take pictures of the ground. It's right behind the amp on the sheetmetal dividing the trunk and passenger cabin.

No digital multimeter. The remote in on the amp comes from the remote out on my Pac 8-channel. The Pac does signal sensing and turns on when you turn the radio on. Then creates the 12v remote signal for the amp.

Amp is the Alpine PDX-V9. I'm running a Rockford Fosgate 4AWG power kit.


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I would talk to Alpine and see what they say. I have a PDX-V9 and Kenwood 9105d (~900 watt RMS mono) with no dropouts. I tried today. I hadn't driven today and the battery was showing around 12.1v and 71% charge in engineering mode. Even cranked up enough to send the kenwood into protection (They claim it's a 1 ohm amp, but lots of reports of issues at 1 ohm) the PDX just kept playing. Both amps are grounded to the chassis along with the battery's ground and come directly off the positive post. Engineering mode showed the battery holding around 11.9 - 12v.
 

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Discussion Starter · #12 ·
Ok. I tried running the remotes into the amp and LOC off the plug by the head unit again and that made no difference. Switched it back so it runs off the signal from the head unit's speaker outputs.

The power comes directly off the positive post and not off those fused links. I wondered why they didn't ground it to the same point as the chassis/battery ground or even ground it directly to the battery since it's so close. I'll get some more 4 AWG cable and try grounding to one of those spots. I've also noticed they ran power and ground to the LOC off the power and ground terminals of the amp. I've read where that's one way to do it. But a better way to do it would be to come off the battery and ground to the same point on the chassis or to the battery. That the way they did it might induce some noise.
 

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I can take pictures of the ground. It's right behind the amp on the sheetmetal dividing the trunk and passenger cabin.

No digital multimeter. The remote in on the amp comes from the remote out on my Pac 8-channel. The Pac does signal sensing and turns on when you turn the radio on. Then creates the 12v remote signal for the amp.

Amp is the Alpine PDX-V9. I'm running a Rockford Fosgate 4AWG power kit.


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sheetmetal isn't an ideal ground. Try a better spot, also try an accessory power line to power the amp turn on. The Pac 'sensing ' could be a problem.
 

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You need to at least be on the floor of the trunk. I usually grab a spot where you can see that the car is spot welded together. Whether you are using a self tapping screw or inserting a threadsert, the double layers are going to give you a better hold. Being up on the bracing between the back seat and the trunk is not ideal because it is not usually welded to the body, but a glue is used so that it can flex some.
 

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Just run your ground back to the battery, once you see the threads on that bolt, you'll never be satisfied with the clamping ability of a simple self tapping screw into the sheet metal. I upped the grounding wire to 0 gauge as well as sanded some paint away immediately around the bolt hole.
 

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Discussion Starter · #17 ·
Did anyone ever use a Rockford Fosgate install kit for an amp? I've got the power only kit but I would think all their kits would use the same fuse holder.

I went poking around at lunch and found the fuse was loose as hell. As in, you breathe on it wrong and the amp shuts off. The set screws were tight but the blades of the fuse were not all the way in.

I disconnected the power cable then pulled the fuse and took the set screws out. Then I pushed the fuse in as far as it'd go and reinstalled the set screws; tightening them down against the blades of the fuse. Felt a lot more secure this way.

After reconnecting the power cable I turned the radio on. The amp didn't cut off when I put the window up and down. Hopefully this did the trick. I also wonder if I should've done this install myself. I'm not to inclined to go back to this place I went.


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Good job figuring it out. It's always better to do it yourself.


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Discussion Starter · #19 ·
The last two days here have been really hot. When I got home, I looked in the trunk and saw the status light if the front of the amp was flashing red. The amp still plays though.

I've been driving in engineering mode so I can watch the battery voltage. Cruising with the a/c going and the radio on, I see 14.7 or so. At a stop, it's about 14.5-14.6. When the radiator fans kick on high though, voltage drops to 12.5 and the amp drops out for a couple seconds.

The whole time the fans are on high, I see 12.5-13.0 volts. The only time the amp drops is if I'm idling when the fans kick on high. I think it could be a combination of the high heat and too low voltage. I ran a new ground cable directly to the battery before driving off tonight. Didn't seem to make any difference in anything. No additional noise from the extra length. No improvement in voltage.

Next step I might get a new battery.


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..The remote in on the amp comes from the remote out on my Pac 8-channel. The Pac does signal sensing and turns on when you turn the radio on....

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Eleminate this. Connect both turn ons together and run it with a relay circuit or a switch just to test it. Also it's not unusual for a system not to play during cranking. The starter is always the larger drain.
 
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