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I fixed a parasitic drain on my car in 408 days

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Re: I fixed a parasitic drain on my car in 408 days

#161

Post by leetrout »

HeyLaughingBoy wrote: post #155
sokoloff wrote: post #106

Earlier quoted context omitted.

> My mechanic won't do it because he won't confirm that's the cause. My experience is that a lot of independent mechanics will do what you ask them to do, so long as they think it’s not unsafe and have confidence that you’ll pay the bill without complaint when the task is done whether or not the problem is fixed. Probably not a good “this is my first time meeting you, but please replace my flux capacitor” but if you’…

Yes. I had a problem with a leaking transmission once and the shop refused to accept my diagnosis because "in all my years servicing transmissions, I never heard of that failing." Finally, the service manager agreed to check it out with the understanding that if I was wrong, I still had to pay for the time they spent investigating. I was right :-)

This was me with a Suzuki vstrom with a bad solenoid. Mechanic ran 12 volts through it on the bench and refused to accept it wasnt working in the bike.

Bought my own solenoid online and surprise the bike started working again.

Re: I fixed a parasitic drain on my car in 408 days

#162

Post by micromacrofoot »

overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

I've been to multiple mechanics, talked to roadside assistance people, posted in multiple forums, and talked to family about this problem with an old car of mine... and they all swore up and down that you should start a car if it sits longer than a weekend, maybe a week tops. They made me feel insane about it, it's one of those widely accepted things that's just not true most of the time.

Re: I fixed a parasitic drain on my car in 408 days

#163

Post by blobbers »

instaclay wrote: post #35
blobbers wrote: post #11

Is it possible the key fob just needs replacement and is causing the intermittent sleep failure?

I was also curious about this. Maybe the keyless entry computer stays awake to try to sync with a fob and then sleeps on success? If a user chooses not to use a fob at all, maybe it stays awake indefinitely trying to find a key to sync with.

Yeah sleep-wake problems often are related to things missing or broken in the (poorly constructed) system.

If the software on the car was poorly written, it may not have had a good back-off on the fob check, or if the fob itself was malfunctioning it may have left the car in a weird state.

While I wouldn't expect a fob to drain a car, it certainly doesn't seem implausible, especially given what the fix is.

Re: I fixed a parasitic drain on my car in 408 days

#165

Post by bityard »

ceautery wrote: post #40

This is type of thing I've seen Eric O. over at South Main Auto[1] fix in dozens of videos. Mad troubleshooting skills, works hard to find root causes of things. He's pretty amazing, hidden away in some no-account town in upstate NY. 1 - https://www.youtube.com/@SouthMainAuto

Although I perform as much of my own auto maintenance as I can, I watch Eric O because he's entertaining, and all of the technical wisdom and advice just comes along for the ride.

Re: I fixed a parasitic drain on my car in 408 days

#166

Post by civilized »

My wife and I gave our old car to her parents. In the subsequent years, its battery kept dying and we had to go over to their place and jump it. Never happened in the prior 7 years we'd owned the car. The mechanic said nothing wrong with the battery, but suggested there might be a parasitic drain somewhere.

A few days later, we were visiting them. I looked at the car and saw the door closed, but not properly latched and ever-so-slightly ajar. You know, that half-closed thing car doors do when you don't close them hard enough.

It turns out someone, possibly my son, had been not closing the door completely. This did not keep the lights on or cause any other visible sign, as it would in some cars.

After I told them to slam the door fully shut, never a problem again for 2 years and counting.

Re: I fixed a parasitic drain on my car in 408 days

#167

Post by JohnFen »

lylejantzi3rd wrote: post #28
overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

> It seems like mechanics really don't like digging into the electrical part of the car... Tell me about it. I'm in a similar boat. My audi a4 has had a parasitic draw for the past 10 years. My mechanic didn't want to take the time to address it because that sort of thing takes a serious amount of time and he's always backed up. I got out my fluke and narrowed the cause to what I believe is the comfort control unit.…

I wonder if installing a switch to disconnect the car's battery entirely would be an acceptable (but obviously hacky) solution.

Re: I fixed a parasitic drain on my car in 408 days

#168

Post by dsfyu404ed »

bronson wrote: post #124
ilyt wrote: post #109

Earlier quoted context omitted.

If car is at the point of engine rebuild you'd probably have to replace half of the suspension too

At least! When my engine finally needed a rebuild, so did the transmission, steering box, CV joints, and center differential. And you're right, it needed new bushings, shocks, springs, and balljoints.

"need" starts being a very subjective word when talking about some of these components at high milage.

Re: I fixed a parasitic drain on my car in 408 days

#169

Post by Dave_Rosenthal »

overthrow wrote: post #3

Well this is timely. I have a parasitic draw on my NC Miata. The first mechanic just replaced the battery. The second told me it's normal for the battery to die if you don't drive it for 3 days (because "cars have computers now"). It seems like mechanics really don't like digging into the electrical part of the car... but these days that encompasses more and more of what can go wrong. Without time to dig into it myse…

I think a cheap thermal camera would be very helpful in these situations with a relatively fast drain. A car battery is ~1 kWh so anything that drains it in a few days is dissipating on the order of 10 watts. In my experience that's very easy to see in a thermal camera. Just leave the car in a nice thermally-stable place for a day and then go hunting.

Re: I fixed a parasitic drain on my car in 408 days

#170

Post by anamexis »

sixstringtheory wrote: post #152

Hah. I’ve replaced the battery in our Subaru Outback on average once per year, which is way too high for this environmental minded person. I just went out last night to grab something from the car and it was making a loud electrical whirring noise. I had driven it several hours prior, no idea how long it had been going. I recorded a video and it is clearly audible. I started it and turned it off again, and the noise…

Ugh, I've also got an Outback (2019) with a regularly dying battery. Let me know if you ever find any leads on the root cause.
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