What's wrong with my car, remote version
July 10, 2020 11:09 PM   Subscribe

I'm in New Zealand. I have a 2008 Scion xB in Massachusetts, parked there since late September 2019. I found out recently that the person who promised to occasionally start and drive the car never did. The car got jumped, but won't stay running, and has been towed to a mechanic. What is likely the problem, and how do I minimize the chances of getting bled by a mechanic I don't know?

The person supposedly taking care of the car went to start it but the battery was dead. She had AAA come and jump it. Then she tried to drive it around to charge the battery (I know, low-speed driving for 20 minutes isn't enough). She drove down a dead-end street and had to turn around. When she came to a stop the engine "sounded like it was going to die." She put the car in reverse, backed up, and when she stopped to shift back into drive the engine stopped and the car wouldn't start again. AAA came back and towed it to a mechanic. AFAIK the mechanic hasn't looked at it yet.

This all happened before I knew anything about it.

The AAA guy said he thought it was the alternator. I think that what the AAA guy thinks is irrelevant. I don't know if it was the same AAA guy both times. He jump-started the car the first time, he did not replace the battery or charge it.

I have to talk to the mechanic when they open in a few hours. I've never used this mechanic. I've had some great mechanics in the past as well as some money-vampire mechanics, but i don't know which kind this will be. My mechanic is on the other side of the country so I can't use him.

I can't really get decent details from the person who was driving the car when it died, but I'm tempted to infer from what she said that the engine was idling too low when it "sounded like it was going to die." There's no way she drove it long enough or fast enough to charge the battery in any meaningful way, so I think there's not enough data to suspect the alternator. It could easily be the alternator, but it could easily be something else.

In my admittedly amateur opinion, it could easily be that the fuel filter has been clogged with sediment, or some other old fuel-related problem (fouled injectors, water in the gas tank...)

The person who was supposed to take care of the car has offered to pay for repairs, but she presents as a classic "easy mark" - she's credulous and is easily swayed by authority wthout verifying its authenticity. I don't want her to be dragged down an expensive rabbit hole of replacing every part in the troubleshooting flowchart. I also don't want to have to deal with finding another mechanic remotely and having the car towed around more than is absolutely necessary.

So, my question is... can I still eat this car? No wait! My questions are... what are the most likely causes of an engine shutting down in a car with a dead battery and 10 month old fuel in the tank, being driven for the first time in 10 months after a jump-start? And what do I say to/how do I approach dealing with the mechanic in a way that minimizes unnecessary repairs? Finally, how can I tell whether I'm dealing with a good, honest mechanic or the other kind, when I'm so far away with few other options to leverage?
posted by under_petticoat_rule to Travel & Transportation (14 answers total)
I bet you need a full battery charge, a new battery at most.
posted by Grandysaur at 11:35 PM on July 10, 2020 [3 favorites]

Fuel can sit for 10 months just fine. Scions are Toyotas, and are highly reliable cars. The battery has nothing to do with it. Once the car is started, the battery is irrelevant - if there's a lack of electricity, the problem is the alternator, or a weird short, but not the battery.

It's difficult to diagnose a car based on third-hand knowledge, but I bet the AAA guy is right. Probably a bad alternator. Hopefully a bad alternator as that's a simple and inexpensive fix. And yes, you probably ALSO need a battery, but a dead battery doesn't kill a running car.

Fuel system should be fine. Source: I just rescued a 95 Toyota that had been abandoned for over a year. Abandoned with a half tank, outside for 13-14 months. Fuel system was fine. Did need a new battery though!
posted by weed donkey at 12:25 AM on July 11, 2020

She put the car in reverse, backed up, and when she stopped to shift back into drive the engine stopped and the car wouldn't start again.

Sounds to me like there's a good chance she just stalled the car and the battery hadn't recharged yet so it wouldn't restart.
posted by lollusc at 12:39 AM on July 11, 2020 [9 favorites]

An animal could have built a nest in the air intake, or chewed up some wiring. Over winter, something could have frozen and leaked. It could be a weak alternator, my 2007 Scion tC tends to idle fast for a few minutes before settling down to a lower idle. Since the battery was dead (like dead dead probably), the little computer that controls the emissions fuel/air tweaking has lost it's configuration and it needs to be driven for about an hour at 50-60 MPH highways speeds for it to recalibrate. That it, there's no way it will pass a smog test before you do that after losing power that way.

I had to do the AAA battery replacement thing last year for my Scion that had sat so long the battery was gone (and the original battery at that!). Then failed smog with the new battery.

I'd just take a quick look for any rodent nests or other obvious things, jump it and drive for an hour at highway speeds, then see if it starts again. It's likely the little computer thing is confused.

Ideally, when you get a new battery at a garage or some place like that, they can backup the emissions computer, change the battery, test the alternator, then restore the computer and all is good.
posted by zengargoyle at 2:25 AM on July 11, 2020 [3 favorites]

Mostly +1 on Zengargoyle. Engine control computers in cars store "learned" calibration data as part of a self tuning process and adapt to your particular engine, including idle speed parameters, fuel trims, etc. (This is to compensate for wear, parts tolerances, variations in fuel quality, etc.) When a car's battery dies, all the stored data is lost and it has to learn from scratch. Some cars require a specific initial learning sequence (for example, one of our Subarus requires starting and idling for 20 minutes after a battery disconnect. If you just hop in and drive it, it will stall at idle, set low idle speed diagnostic codes, etc.)
I think a fresh battery and going through whatever initial learning procedure this car requires is all it's going to need. I think the alternator is probably fine, at idle many cars produce low alternator output and if the car is idling lower than normal due to having lost its engine calibration data and the battery is weak that's a recipe for wigging out the engine control computer.
posted by Larry David Syndrome at 5:38 AM on July 11, 2020 [2 favorites]

Fuel can sit for 10 months just fine.

Recognizing that real experience often trumps the internet, virtually every source out there says that gasoline starts to go bad at between three and six months.

Replacing the fuel can’t hurt, and the general wisdom seems to be that it’s a good idea.
posted by Tell Me No Lies at 5:45 AM on July 11, 2020

Talk to the mechanic after they look at the car and after the battery has had an opportunity to charge. If your gut says not to trust the mechanic, there are MeFites in Mass. Post to jobs to see if anyone will take a 2nd look.
posted by theora55 at 7:24 AM on July 11, 2020

Seconding getting a full charge before any other efforts. That could be all it needs.

I live in MA, but don't have a mechanic to recommend. I did have a reliable one, but he sold the business to some guys who started presenting what felt like questionable repairs. I started going to the (Subaru) dealer, and have been satisfied with them.
posted by Kirth Gerson at 7:47 AM on July 11, 2020 [1 favorite]

Thirding full charge, new battery. Most of the time this will be all it needs. I have left multiple cars sitting for at least that long on various occasions (including during COVID), and never had anything other than the battery die, so far. Tell the mechanic to start with that and let you know if it doesn't solve the problem. The AAA guy is slightly more reliable than your car person, but neither is likely to know as much as a basic-ass mechanic.
posted by aspersioncast at 8:33 AM on July 11, 2020 [1 favorite]

Meant to add that an alternator needs more than a drive up the block to charge a battery; I would never assume an alternator problem without more tests in your situation.
posted by aspersioncast at 8:36 AM on July 11, 2020

If your fuel system is not in good condition and is open to the air in any way, and if you have ethanol in your fuel, then you can accumulate water in the bottom of your tank as the ethanol grabs water from the air and subsequently drops out of solution in the gasoline. When you move your car around, this low energy water ethanol stuff can be ingested. It fits the report of low/rough idle and stall.
In addition to changing/charging the battery, you might want to get a "dry gas" additive to add to the tank if you don't replace the fuel. You might top off the tank with fresh fuel. If you add dry gas or new fuel or replace the fuel, I would expect to have to crank it longer before it started, when the hypothetically bad fuel is cleared from the lines.
posted by the Real Dan at 10:18 AM on July 11, 2020 [1 favorite]

This has happened to me a couple of times with a shorter period of non-operation of the car. Once it needed a new battery and once a full-charge using a slow-trickle charger worked.
posted by quince at 10:30 PM on July 11, 2020

As a shadetree mechanic, I think it's a combination of things others have mentioned above:
-Many modern cars "learn" various engine control settings, fuel mixture, sometimes timing, etc. that can be lost when the battery is replaced or fully discharged.

-Allowing a lead-acid battery to fully discharge (or even just get low) can permanently damage its ability to hold a full charge.

-As others have said, I'd check the air intake for a mouse nest, but I'd also carefully check for chewed wires. The mice around here find the injector control wires on hubby's Mazda delicious, for some reason. The telltale here is that the Mazda would start, but it ran incredibly rough because one of the injectors wasn't working.

-The alternator is unlikely. Unless the car was parked in an extremely corrosive environment and shows other signs of that, alternators rarely go bad from just sitting there. If it was working fine before it was parked, it is almost certainly still good now (unless wiring got chewed.)

Start with the simple, inspection-related things and work up from there. Check air intake system and filter. Visually inspect wiring for chew damage. Replace the battery. Any good, trustworthy mechanic will do this as a troubleshooting step (paying for their time) without requiring you to buy the battery up-front. Could also be a dirty fuel filter, but I really suspect you're gonna need a battery and there's probably crap in the air intake.
posted by xedrik at 8:19 AM on July 12, 2020

The mechanic tested everything and said it was just the battery.

Thanks everyone!
posted by under_petticoat_rule at 2:26 PM on July 15, 2020

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