Electrical problems

[Kizashi570]

Hey guys, haven't been on the forums in a while but I'm at a point of slight desperation. 2 months before Christmas is not the time I can afford to dump a bunch of money into my car for diagnostics so I'm hoping you guys can help.

Background: 2010 Kizashi SLS, AWD, CVT Trans. 50K miles.
Have aftermarket low-beam bulb + ballast, fog light bulb + ballast, high beam bulb + ballast + capacitor installed. In addition I replaced the factory rockford fosgate sub with an aftermarket: The sub maxes at 2500 watts, the amp at 1400 watts.

I do NOT have a capacitor connected to the sub.

My problem: Occasionally when driving (every 30ish miles) my car will give me a light jerk, like it's struggling to change gears. More noticeably, every time I slow down to a complete stop, the car feels like it is close to stalling out - my RPMs dip to 300-400. I've driven a stick my entire life (before getting my kizashi) and the feeling is almost identical to being stopped in a standard and slightly lifting my foot off the clutch while the car is in gear. The car has never actually stalled out.

My first thought is that this is a transmission problem. Then I connected the dots and remembered that my car battery had died 2-3 weeks ago despite nothing being left on. For the last 2 days I have been driving without any lights on (I disconnected the daytime lights) and I manually turned off power going to my aftermarket amp. The problem has stopped. Here is where I conclude this is an electrical problem.

I'm not going to pay $140 for suzuki to run a diagnostic when I know that it's not going to be covered under warranty. I have 3 ideas, I'm hoping 1 will fix this issue, and I'm hoping I don't need to try all 3 to find the right one:

1. Get a capacitor for my aftermarket stereo.
2. Upgrade my battery.
3. Upgrade my alternator.

Open to advice, ideas, or suggestions. I'm going to try to get my battery tested today so I'll edit this post once I get those results. Obviously, my aim is to fix this problem without spending a lot of money.

Thanks! -Ben

[KuroNekko]

I'm no electrician, but it sounds like your accessories are drawing too much power. The alternator cannot keep up. The battery starts the car, but the alternator is the one that is powering the car for the most part when the engine is running.

All your electrical toys are consuming too much power and is not leaving enough to keep the car running normally. The alternator may even have a hard time recharging your battery hence the dead battery you had. As the weather gets colder (assuming you don't live in Australia) it will only get worse.

I would suggest your rethink your audio system and tone down the ridiculous wattage. That kind of wattage is what makes cars rattle and sound like shit anyway. Even if you don't blast your system, it's going to draw too much power.

Also, HIDs in high beam is not a good idea. HIDs require a warm-up time (usually around 20 seconds) and high beams are often used sporadically for signal flashing or temporary use in dimly lit areas. For this reason HIDs are a bad choice for high beam use. Not sure if you have capacitors to help with this or just to deal with the DRL function, but HIDs in high beams is something that is usually not done for the reasons above.
This is why even high end cars don't use HIDs for high beams unless it's bi-xenon (these are where the low and high beam bulbs are the same and the difference is the tilt of the lens in low vs. high).

I suggest you take out the high beam HID kit and install a quality halogen bulb like I did. PIAA, Hella, IPF, Osram, etc. all make good bulbs for this purpose.
This will help to reduce current draw as high beams are hardly ever used for most people and DRLs run at low wattage. Your HID kit and capacitor are drawing more power than you can get by with so dump those since you don't need it in high beam usage.

If you still want to run your sound system and lights, you need to upgrade your alternator and get something like an Optima battery.

As you know, all these would void Suzuki warranty and the fact that your car returns to normal when you disconnected your accessories proves they, not the car, are the problem.

[Kizashi570]

Thanks for the advice. Upgrading the battery/alternator would void my powertrain warranty?

[KuroNekko]

Thanks for the advice. Upgrading the battery/alternator would void my powertrain warranty?

Battery, unlikely.
Alternator, most likely.

[Ronzuki]

If you still want to run your sound system and lights, you need to upgrade your alternator and get something like an Optima battery.

Better make it a Yellow Top Optima.

[LPSISRL]

I would agree with Kuro. The shudder coming to a stop is common with CVT Kizashis, especially if you're braking a little hard. There are other posts about it. However, the RPMs are not dipping as low as your's. That could be due to the added load on the alternator as it tries to deliver enough current to meet the demand, including the charging of the battery which could be significant. However, I would confirm by connecting everything back up and see if the problem returns. My troubleshooting philosophy is to fix the problem, remove the fix and see if the problem returns and then apply the fix again. Only when practical, of course. You didn't mention that once stopped does the idle come back up? Other symptoms of too much load would be dimming head and dash lights at idle with them getting brighter when increasing RPMs.

[twoqttsdad]

Sounds like an SPL amp. 720 watts RMS? In any case I wouldn't run anything more than 300 watts RMS on the stock alternator. Anything more and I would recommend upgrading the alternator and adding a dual battery isolator and a second battery. Another $700!

[murcod]

That amp won't be drawing 1400 Watts all the time - in fact it shouldn't be drawing much current at all, unless you have it cranked up very loud. Try driving around with it disconnected from the power and see if the transmission problem is still there.

[LPSISRL]

Watts=volts X amps. I don't think that's changed since I went to electronics school even though it was many years ago. (no Ben Franklin was not in my class) Amps = watts/volts. 1400w/12v = 116 amps. Doesn't compute. Said another way, in a 20 amp circuit, the max watts you can draw before blowing the fuse is 12v X 20a = 240 watts. 30 amp circuit is 360 watts. I've always wondered how these hi-watt ratings circumvent the laws of physics.

[Ronzuki]

time delayed vs. fast acting fuses.