My sisters car died while it was in park, she said it started right up when she got in it, Then she went inside while it warmed up, when she came back out it was dead.

I told her that it was probably her alternator that drained the battery and the car and that's why it's ticking when you try to start it now

But can there be anything else that will kill a car while it's sitting in park, if it started right up a few minutes earlier ?

Update: car was checked out and it's not the battery or the alternator, theyre voth good, and the car has full power. a few other people checked it out and said it was the fuel pump so I checked the fuel pressure, and there's no pressure at all, swapped out a fuel relay and swapped out a few fuses to the fuel pump and still nothing, I'm having a hard time thinking it's the fuel pump because the fuel pump primes when the key is turned to on, so I did a OBD scan on it and it came up the MAF sensor but that's probably because of no fuel right, so could it actually be the fuel pump or is the MAF keeping the fuel from pressurizing, even if the fuel pump is priming ? No fuel pressure. Fuel Hoses looked good under the vehicle

Another thing I find rather odd is that the autel OBD live data shows that the fuelsys1 to be reading -- instead of OL or CL like it's not getting a signal, but I can hear it hum for about 3 seconds, I'm trying to talk myself out of it being the fuel pump :)

Update: #2 So I removed the fuel tank and the fuel pump, I tested the tank weight, it was good, I tested the tank sensor, it was good and the other part had continuity that looked like a filler cup so I'm guessing it was good, but here's a shocker. There was absolutely no fuel, nothing, nada, zilch, the gauge was reading 1/2 tank, which was odd, the next thing I found was that the fuel tank wiring harness for the fuel tank sensor, found one of the wires hanging on by a thread, so there was some sort of reverse effect I'm suspecting, now I just have to put it back together and hope, no gas and a bad wire was the issue.

  • Fuel pumps can act up in such a way sometimes. But sounds like an alternator.
    – E.Flint
    Nov 29, 2018 at 6:52
  • 1
    What you need is data, use a multimeter to check the battery voltage.
    – GdD
    Nov 29, 2018 at 8:21
  • I'm going to run some tests after work with a multimeter , I just wanted to get some insight about what could kill a car in park, found that kind of wild, all I could think of it being was the alternator draining the battery... I really need to get a oscilloscope one of these days
    – user38183
    Nov 29, 2018 at 8:24
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    I can't think of many cases where an oscilloscope would be useful on a car, a multimeter is extremely useful though. The insight I would give is not to speculate, but test, you could spend a lot of money on what it could be but I completely understand where you are at with this.
    – GdD
    Nov 29, 2018 at 8:28
  • @GdD and Solar Mike check out the update
    – user38183
    Nov 30, 2018 at 1:29

3 Answers 3


I think you possibly have either a faulty battery, or fuel supply issue.

It is unlikely the alternator drained the battery, especially in just a "few" minutes. An alternator fault capable of doing that is basically a dead short and will have melted the wiring...

  • the battery was just replaced not that long ago
    – user38183
    Nov 29, 2018 at 8:15
  • Ok, but still worth checking - new batteries can have an internal link fail just as older ones can... I have seen faulty batteries of all ages.
    – Solar Mike
    Nov 29, 2018 at 8:16
  • I'll check that out, but if it was a fuel line would the first start have caused a problem before she walked inside
    – user38183
    Nov 29, 2018 at 8:18
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    if the fuel line was drawing in air slowly, then it could have started normally then died once too much air had entered...
    – Solar Mike
    Nov 29, 2018 at 8:42
  • If the fuel pump was faulty the engine would still crank @SolarMike. From the sound of it it's just clicking.
    – GdD
    Nov 29, 2018 at 8:53

The fact that the car died when it was running and is ticking over now does very much sound like an alternator to me, although it could be a faulty battery as well (even new ones break sometimes).

A scenario that makes sense is the alternator was already failing or failed on the previous drive so the battery could have been barely charged enough to start the car, then running drained it.

Other less likely scenarios:

  • Starter motor failure: the clicking is probably the starter switch, if the motor has gone it won't crank. That doesn't explain why the car quit but maybe it just did
  • Computer failure: not very likely, the engine would probably still crank
  • Engine seized: it could be the reason it isn't cranking is that it can't, maybe a catastrophic oil leak occurred and wasn't noticed

Sounds like a faulty float on the fuel pump, over time their contacts will wear out giving a false positive to the driver.

That would indicate why the driver was seeing 1/2 a tank, the vehicles ECU assumed it had 1/2 tank so the vehicle started with the residual gas that was remaining in the tank. Then it died while still reading half a tank of gas.

But like you mentioned, a frayed wire can cause a higher resistance which may cause the malfunctioning.

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