any one know if this is bad for the car at all? this happens usually when i have my stereo system up high, and the bass is hitting pretty hard... when i shift, the car jerks... and the only way to get away with this is to turn my volume down everytime i shift, but this is just annoying. I just want to know if this is bad for the car at all?

 

It sounds like your electrical system is not capable of supporting your stereo. In a car like the G this could be devastating. Everything in the G is computer controlled. To make something computer controlled very precise voltage levels are needed. For example - your throttle position sensor (the sensor that tells the ECU how far you have the pedal down) operates between 0.00VDC and 4.6VDC (if I remember right). If your stereo is causing the overall voltage of your car to fluctuate at such a rapid rate that your transmission can't shift right then I'm sure in the long run you will have numerous other electronic problems.

I guess the point I am trying to make is that most of the things that used to be mechanical are now electronic in the G. That being said, if you have an unstable electrical system you should plan on having an unstable car.

To remedy the problem you have a few options. Removing the stereo would be the easiest.

Next up would be replacing the battery with an Optima yellow top - a great battery for big stereos. Next up would be a higher output alternator. Very expensive, but the right way to fix the problem. If you are just looking for band-aids to the problem throw a 1f cap in the car, it might help, but like I said, its only a band-aid.


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

sigh i hope this is not why my service engine lights keep coming on now... im just worried... the yellow optima battery replaces my battery or is it just a 2nd battery for my car? can you please show me which optima yellow top to get, i was told it wouldnt fit my car...

 

well i get the same thing too. So i turned my bass down and i am going back to replace all the wiring to the alternator to my battery and going to get a second OPTIMA battery1 Sigh...

Ed

2003 Transport V35SKYLINE. Team Transport! www.teamtransport.org

 

g35lin, what do you mean replace your wires? Will this correct the jerky shifting problem? Explain more please.

 

You can't exactly just add a 2nd battery, its not that easy. A 2nd battery will add more of a load to the already taxed alternator. If you do add a 2nd battery you NEED to install a battery isolator with it. This way only one battery at a time will be connected to the electrical system. The isolator is basically a high current switch. The purpose of installing a 2nd battery and isolator though is to increase engine OFF playing time. With the battery and isolator installed you can play your stereo all day long with the key off, and then the isolator will switch to your main battery to start the car.

If you are going to add a 2nd battery to your G you MUST upgrade your alternator. It may work for a few weeks or months, but eventually you burn up your alternator. With a big stereo in the G most likely this will not be covered under warrenty. I would hate to guess how much it would cost to fix a bad alternator, as it would have to be done from the bottom of the car and would be a major pain.

I have no idea what model to get, but I know people have got them. You need to special order it because our battery terminals are backwards from most cars. Any Optima dealer should be able to assist you with the correct choice.

For a little more theory behind all this:

The battery of a car is designed solely for starting the car and then stablizing the voltage of the alternator. Cars are actually designed to run off of the voltage created by the alternator, not the battery. On most older cars once the car is started you can remove the battery all together and the car will keep running. Once you start pulling more current then the alternator can deliver the battery will make up for the difference. However, now that battery needs to be charged back up, creating yet another load for the already overworked alternator. Eventually, over time, you will just run out of availible current and very bad things will happen to your car/alternator. I've heard rumors of low/unstable voltages frying BCMs and ECUs, but no one has ever been able to prove such a theory.


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

In addition, replacing the wiring between the alternator and battery typically isn't necesarry. When you run a wire a short distance it can handle much more current. There is a chart availible (ask your installer) that tells you how big of wire you need for 'X' amount of feet and 'I' amount of current. I have no idea what size the G has, but most likely it would be sufficient.


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

ok so can you confirm that this is bad driving with the car at high volumes? Will it damage anything? The only thing that bothers me is the jerky shifts when I have my stereo up and i just want to know if this will damage my car in the future... its fine when my car is in gear tho... it only jerks when it shifts up, but once its in gear its fine... this is really worrying me...

 

The thing about electronics is you never know. It is very possible you could damage any of the electronic components of your car by creating an unstable voltage level. If you read your manual I am sure it will tell you not to add anything to the electrical system bigger then 10A or so, as the electrical system is not designed to support it.

I used to drive a 94 Cavalier that I had 2 amps in, producing 1200watts RMS. When I turned it up my ABS light would come on and stay on due to the unstable voltage level, even with a 1F cap. After I upgraded my battery it never did it again. If I were you, I wouldn't push it as the ECU And BCM are both very expensive.



Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

hum.....thats very valuable information right there. So i have to upgrade my alternator for sure if i want a second battery? Hum....i gotta do more research.

Thanks for the headsup Kpierson.

Ed

2003 Transport V35SKYLINE. Team Transport! www.teamtransport.org

 

It is general car audio knowledge that adding a 2nd battery without upgrading your alternator should be for car-off listening only. To be honest, I have no idea how big the stock alternator is, although I do have a spare one sitting in my garage that I could look into next time I'm home, and I have no idea how much current the car is capable of pulling.
These are the factors that would determine if you could add a 2nd battery without upgrading the alternator.

I don't think any reputable car audio store who knows what they are doing would perfom such an install.

Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

I guess I will chime in to help answer some of these questions. I would say that yes, you could damage ecu as well as many other items when you have voltage issues. Also you can add a second battery to just about any vehicle without adding an alternator. I would rarely recommend an isolator. They are not as much like a switch as they are a giant diode and you lose about a volt in heat. That is why they have a heat sink. You would be much better with a solenoid to separate batteries if you want one for starting and one for a system. Being that the original question was a voltage issue you have a couple ways of stabilizing it. The stock alternator is 110 amp which is actually not too bad. I have the same size on my f-250 that has two group 34 batteries in parallel from the factory which shows that a second battery would be a possibility. By adding an alternator you may also be able to solve the voltage issue but at much higher expense. By putting the second battery in the trunk you will reduce the amperage needed by having less line loss from such a long draw which will help stabilize the voltage. Also, when you run amplifiers that are regulated power supplies you need to understand that as voltage goes down amperage draw goes up, which is one more reason to stabilize the system in the back at the amps. I would say that adding an alternator is a good idea but you will spend some $$ to do it in a G. I would upgrade factory wiring it will reduce line loss by going larger and adding better ground should help. That is why all these ground kits are being sold to help performance they help stabilize voltage.

Josh
SoundAdvice

 

ok, im going to disagree with everyone here, but only because I first reported this problem 6 months ago, and after LOTS of digging, I corrected the problem. I wont say I truly isolated the issue, just that It no longer occurs.

I too thought this was a battery issue. SO I replaced the battery...without any improvement. Josh at Sound Advice told me this might be because I don't have the battery grounded as part of my grouding kit. I checked and it was grounded, but to be safe I replaced it with a better ground...still no improvement.

I thought that maybe it was the alternator...so I had infiniti first replace it with another stock one...no help, and then bought a larger aftermarket one...still no improvment.

So I re-wired everything in the stereo, replacing all my wires with higher quality wires, higher gague, etc...still no improvement.

I added a digital cap to the set-up...waste of money outright. I even tried swaping my amps for a different brand at the same wattage...still the problem persisted.

Then I replaced the headunit with a Pioneer AVIC-N1...NO MORE SHIFT PROBLEM! I used a dual-din kit and *** AC controller and changed nothing else except the radio and the problem has never returned. The new headunit is literally twice as loud as the stock, and I can bring my speakers to distortion without any hiccups in shifting.

I can swear you all said I was crazy when I first reported this

Ed, I would see if you still have the problem after your big super secret upgrade next month. I'll give you $5 if you still have the problem with that AVN

My Team Transport Profile

 

Adding an isolator that is essentially a diode would offer zero benefits. For those of you who don't know what a diode is, a diode basically blocks the flow of current in one direction. If you installed a diode between your alternator in a 2nd battery it would allow you to 1) charge the battery but NOT use power from it to start the car or 2) allow you to use the battery to start your car but NOT let the alternator charge it.

When I said add an isolatorI meant use a device that never lets two batteries be 'seen' by the alternator at the same time. When the key is 'off' the 2nd battery would be connected. As soon as you turn the key on it would switch to the primary battery to start the car. The isolator would then switch between the two batteries while the car is running in order to charge both batteries but NEVER stress the alternator with two batteries attached at the same time.

Honestly, I have never installed or even used an isolator, but I did read every issue of Auto Sound & Security for 3 years and this topic came up often.

As far as the head unit making a big difference... I have seen stranger things, I wouldn't rule it out in being the problem. However, I think the real solution here is to be a man and drive a 6mt


Kevin
www.KPtechnologies.net
AIM: KPiersonTec
04 DG Coupe / VDC Memory
OEM Remote Window up mod
Procharged / Crawford / TS

 

lol...some of us like to drive with one foot hangin' out the window.

I have seen stranger things too. G35lin is having the same problem in his and we are swaping his headunit for an AVN this weekend. So if this takes care of the problem again then it is more than just a coincidence.

I'm sure he'll post the results next week.



Sound Advice of Mission Viejo