Today I was happily driving down a highway at around 60 mph when my car (automatic transmission, Hyundai) suddenly downshifted. I tried to accelerate but the car didn’t respond, just continued slowing down. The oil and battery lights came on.
I was able to get off the highway and pull over. The car wouldn’t start again. It cranked, but wouldn’t turn over.
I had it towed to my shop, but it’ll be a bit before it’s diagnosed. So what the hell is wrong with my car?
Sorry, I meant to put this in IMHO!
Is your fuel tank on empty? Sounds like the motor just died. If not out of fuel it could have been any number of causes. No opinion here would be of much help at this point, we would all be guessing.
Bad alternator/battery?
When you ‘tried to accelerate but it didn’t respond’, did the engine rev but it didn’t go any faster or did nothing at all happen?
I’m guessing nothing and I’m guessing the engine died.
That could be a lot of things without anything else to go on. Alternator. Some random wire that tells the plugs when to fire finally rubbed all the way through and broke. You might just be out of gas, everyone thinks they’re not, but it happens. I spent quite a while trying to get a pick up running. Turns out it was a gas…and had a bad fuel gauge. I knew I had gas and I it said 3/4 of a tank, I just didn’t know the gauge was stuck there and all the gas poured out.
Yea, no dice on the gas - I just filled up yesterday.
Thanks for the feedback. I’d guessed it was possibly the alternator, but hopefully the shop can get it diagnosed tomorrow.
If the car turned over but didn’t start I doubt it would be the alternator. I am thinking it blew a fuse for the fuel pump or one of the ecm controls. If it blew a fuse you have a short most likely
Could be any number of things:
Bad fuel pump or blown fuse.
Bad crank-angle sensor.
Bad cam postion sensor.
Something wrong in the fuel injector system.
Bad ignition coil driver.
Moderator Action
Off to IMHO it goes (from GQ).
Probably not. The car doesn’t need a functioning alternator to run. The alternator charges the battery, and the battery keeps the car’s voltage reasonably steady and also starts the car. The car might not run with a completely flat battery, but you can remove the alternator and the car will run just fine, until the battery gets almost completely drained. If the battery was drained, all you’d get would be a click and all of the lights would go out when you turned the key. It definitely wouldn’t crank.
Did you happen to notice if the speedometer (and also the tachometer if your car has one) kept reading correctly or if they both went to zero?
Since the oil and battery light both came on, you didn’t have a complete electrical failure. You might have a partial electrical failure, but you definitely don’t have a complete electrical failure.
The old saying is that a car needs two things to run - fuel and fire. At this point you’re missing one of them. Fuel could be the fuel pump, which could have mechanically failed, or the circuit driving the fuel pump could have a fault, or there could be debris or rust in the tank that clogged the fuel pump or fuel filter or something in the fuel lines. You didn’t mention the smell of gasoline, so I’m guessing your fuel line didn’t break.
Fire in this case means spark. Again, all kinds of possible problems here. It could be any number of sensors as was already mentioned. It could be that the engine computer itself died. It could be an electrical problem like a shorted wire or a broken connection that caused power to be lost somewhere in the ignition system. I don’t know your car’s electrical system. It may have a main relay that cuts power when you turn off the key, and that relay could be broken or the electrical signal from the key could be broken. All kinds of possibilities.
If there are any other minor details you can remember that might help us narrow it down a bit, but right now there’s just too many possibilities.
If one of our professional car dopes comes in they might be able to say what is more likely for your specific model of vehicle based on their experience, but without more clues I think even they will be guessing quite a bit.
Could be an issue with the fuel system. Either the pump, the fuel line, or something else.
My first thought was fuel pump.
Although, depending on how the car is wired, it could be the started. I was driving a borrowed Honda from Indiana to DC, when the starter went out, and it did exactly what happened to you. I paid for a new one, had it done while I waited, and told the person I borrowed it from “BTW” she was decent about it, and paid me back the money, since it would have gone out anyway, at that time, whoever had been driving it. I was prepared to eat the $150 dollars or something (it was 1987), since she was letting me use it for free because I was 20, and too young to rent a car. but she returned it.
It’s probably not the case, but like I said, that’s pretty much exactly what happened with me. I did everything to get that truck back up and running and nothing did it. I finally, on a whim, dumped 5 gallons of gas in it and it started right up…as the gas spewed right back out.
It was actually the bad gauge that helped me figure it out, it wasn’t where it should have been for how much I had driven it since I filled it up.
Again, I’m not saying that’s the case, I’m just saying it’s easy to overlook. Just because you put gas in the tank yesterday, doesn’t mean it’s in there today. The mechanic will probably glance at the gauge.
While I could see a problematic starter cause a car to crank but not start (especially if you don’t know what to listen for), I can’t think of many times it would cause a running car to die.
Had a very similar problem. The shop I had the car towed to couldn’t find a damned thing wrong. I picked the car up and went directly to a dealership where I traded in on a new vehicle (it was that time).
None of the things suggested would have made your automatic transmission downshift. Eventually, when things start to slow down it would go into lower gears, but you sound like that’s what initiated it. With all going on at the same time, I’m suspecting a PCM (powertrain control module) going out or a ECM (engine control module.) Please keep us apprised.
Update: Timing belt went, despite not being quiiiiite due for replacement. As Hyundai uses interference motors, this was fatal.
Thanks, everyone!
Certain things will throw the car into limp mode which I believe locks it in 2nd gear. However, I have no idea what happens if you enter limp mode already at speed and we don’t have a ton of details from the OP*. If the car is smart enough to put itself in limp mode, I would think it would know enough to stay out of 2nd gear at 60mph. Even if the engine isn’t running, it’ll still be redlining.
*I mean, I know we know it was the timing belt, just that we don’t know the exact sequence of events, like was he cruising at 60 and it just down shifting to 1st, the beginning screaming and he slowed down really really fast?
Ouch!
Ow.
Damn. My sympathies about that. But yup, timing failure would be catastrophic shutdown and non-starting even if the starter cranked the engine.
The one case of timing failure I experienced, cranking told me the entire story – because the valves were all in various stages of open, there was no compression, so cranking had no resistance. It sounded just like free-wheeling an electric motor, which it effectively was. But that may not have been the case for your particular engine, or particular failure.