Misfires

JSur

Has anyone ever experienced power draw that drains the battery within days and fuel cut/misfiring from a bad starter and alternator? The car has been acting up pretty bad recently and my starter just fried. In the process of figuring that out we discovered my alternator is on the way out the door as well. Any accessory, when my voltage got low enough, would trigger a misfire or lean out on me. It even got bad enough at one point to where the blinker and auto window up/down would trigger a misfire or fuel cut. I’m currently going through the car and all it’s fuses etc but I would like to hear your thoughts and opinions on whether a bad alternator and starter could be the root cause of this power draw that’s been haunting me. Thanks


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dts3

What is making you call it a low voltage condition? If your alternator is on it's way out, I'm curious if maybe it actually caused a voltage spike that blew your starter motor. If this is what happened, anything that's got a 12v line is in theory fair game. In the lab, we've ESD'd circuit boards that have failed in such a way that makes it hard to figure out what has happened. They would half-way work, but do all kinds of crazy ****. We had one case where a voltage spike killed a capacitor on a circuit board, but it failed closed (causing a short). This in turn caused it to destroy any other electronic hardware that it was plugged in to... almost like a hardware (as opposed to software) computer virus. I mention all of this to point out that transient voltage spikes can ruin things in very unexpected ways. Hopefully it can be diagnosed without spending money replacing many things.

JSur

I don’t think it’s all tied to low voltage but the symptoms significantly decreased when I threw in a new battery. I believe the low voltage is just a product of the starter and/or alternator slowly going bad over time. The cars creeping up on 90k, has been boosted for over 30k, as well as a bunch of accessories that require lots of power. I’ve been told that a bad starter solenoid can cause a power draw. I’m hoping that by replacing those two parts it’ll, ideally, solve the power draw mystery, or at least bring me back up to par so I can properly track down the issue.


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mults

I am curious about your term "the starter fried". Did it smoke and need to be replaced, or have other symptoms?

As-far-as low voltage, it can be many things...Are any of the wires close to the hot components of your TT setup that could have melted? How low does the voltage get when you say "low voltage"? Is the voltage measured at the battery, or are you going from the voltmeter?

Electrical issues are undoubtedly the hardest to track down. Keep us posted as to any other symptoms or fixes...

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JSur

The starter smoked, we did manage to get the car started after rocking it back and forth, but it is getting replaced. I’ll be ordering the starter and alternator this week.

The AAM Kit is super tight so there’s definitely a few things close. I haven’t dug that deep into yet. The only wire I can think of off the top of my head that run close are the 02 sensor wires and my AFR. I ceramic coated my down pipes and zip tied the wires as far away as I could without pulling too hard. I used a meter. The voltages measured 12.47 when it was off and around 13.1, give or take, while running. Which may not be an issue for regular cars but as I mentioned to the first guy I have A LOT of accessories that draw power. I have air compressors, head unit, amp, capacitor and a remote start system (left over from the previous owner which I’d like to rip out but can’t find it).

I’m really hoping that it’s not a melted wire or a short. Electrical issues are without a doubt the worst lol. I appreciate the input I will definitely update as I go along.


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SouthArk370Z

The starter shouldn't be the problem. Alternator - maybe; but it sounds like it's charging the battery, so it's low on my list at this point. Since the battery is discharging, I suspect an intermittent short; possibly related to the turbo install. Check system voltage with a meter. A recording meter will help spot intermittent problems.

Edit: Didn't fully read previous post. You have low voltage, so the alternator jumps to the top of my list.

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bunk

FWIW, on my gf's focus, the engine would rev close to stalling when idling and you turn on the AC. Couldnt figure it out til the starter gave out, and found a frayed battery cable.

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JSur

Yea the alternator is barely charging the battery. It’s really only charging enough to keep the thing alive. Along with a new starter I’m replacing the alternator. If those solve my issues I’ll be super excited lol. If not, I’m just gonna have to do some more digging.


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JSur

This power draw has been haunting me for a really long time. But inly recently has it been bad enough to cause all the misfiring, leaning out etc issues. Before the starter went out I was just telling a friend of mine that whatever’s wrong with the car, I wish it would just break. Idc if its a little more money to replace if it’s broken but at least I know wtf was going on. It was driving me insane. And 3 days later the starter fried and here we are lol.


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bunk

Yeah, if your TT setup makes things a little tight in the engine bay, Id check the battery cables for frays or any oil/fluid leaks that may have sprayed into your starter or alternator.

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dts3

You should want the problem to be that simple lol. It'd be awesome to crawl under the car and visually see a few melted wires that can be easily replaced in five minutes.

JSur

If I can visually see the wire then yea that would be the ideal situation lol. I was talking about if I have to track it down and run through the whole thing. That would suck lol


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dts3

Yeah lol, I was only thinking about it from the positive outcome

Ghostvette

If issues decreased with a new battery, then there are several things to consider. Reading through the posts, it appears you are replacing the alternator, that's good. Based on the numbers you posted, 13.1 VDC is barely enough to keep the battery charged, much less run everything else. A good alternator puts out between 13.5 & 14.5 VDC. Check all your grounds, make sure they are all clean and secure. A bad ground will raise havoc in any electrical system. If you are running an amplifier and not running a 1 to 2 farad capacitor, you are killing your alternator. Just some thoughts... good luck.

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JSur

I do have a capacitor for the sub/amp. I actually re-grounded them both straight to the frame a while back. They were originally installed with the ground from the amp going to the capacitor ground, then into the frame, so I gave them both a direct ground and that didn’t fix anything. If my battery still drains after replacing alternator and starter then I have to dive into all the grounds. Thanks for the input


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