Car wouldn’t start. Then it did.

ripplyuk

It started fine this morning but when I went to drive home, it wouldn’t start. I tried again and still nothing. All the lights on the dashboard were working and there was no sound of the engine turning over. I took the key out, tried it again and this time it started straight away. I’m not sure what to do. Should I take it to an auto-electrician? My friend said to forget about it and wait and see if it keeps happening but the car feels unreliable now. I don’t want to risk getting stuck somewhere. Though I also know mechanics often find it difficult to diagnose intermittent faults. 

The battery is still under warranty but I’m not sure it’s a battery issue. The car has had other electrical issues earlier this year, when the wipers weren’t responding. The mechanic replaced the body control module to fix that and it’s had no other issues until now. It’s a 2014 Volkswagen UP. 

Bonniepurple

Petrol or diesel?  Were you parked on a slope (even gradual)?  One car I had was an intermittent starter until I realised that where I was parking it was on a gradual slope and if the fuel level wasn’t high enough it wouldn’t get through to the engine.  Reversing the car in solved the problem.

ripplyuk

@Bonniepurple It was a level surface. Maybe a slight incline. It’s a petrol car with 3/4 of the tank full. 

marlot

It could be the immobiliser.

It could be that the key barrel is worn.

It could be that there's a bad connection.

angrycrow

Most immobilisers don't stop the engine turning over they just stop it firing. Engine not turning over suggests its not the immobiliser.

Did the key actually turn as its not unheard of for vag ignition barrels to jam intermittently. It's due to a pin in the bottom of the barrel that snaps off. Tends to be more of an issue on hot days strangely.

The other possibility is the starter motors on the way out. 

It's very unlikely a failure to turn over will have logged a fault code so not worth paying a lot of money for diagnostic. Give it time to see if it happens again and note down exact symptoms if it does, like do the dash lights dim when it fails to turn over which would point to low battery charge. 

Bigwheels1111

Not turning over, first is battery.
Second starter motor, clicking when key turned is dead battery, but no sound could be starter motor.
If manual transmission put in first gear release handbrake and rock car forwards and backwards.
Take out of gear and try starting. Put handbrake on again.
I would get a cheap OBD2 fault code reader and read codes.
That might help.
Do you have breakdown cover, call and say it’s not starting.
When they come out don’t mention it’s done it before.

knightstyle

Diesels often take a short time before the starter starts in cold weather this allows the heaters to warm the combustion chamber and helps the diesel ignite.

ripplyuk

angrycrow said:

Did the key actually turn as its not unheard of for vag ignition barrels to jam intermittently. It's due to a pin in the bottom of the barrel that snaps off. Tends to be more of an issue on hot days strangely.

It might have been that. My hands were a bit numb from the cold at the time but something felt different about it, as if it needed to turn more. Perhaps it un-jammed once I took the key out and put it in again. 

I’ve had no problems with it today. It started fine each time. I just don’t like having to worry that it’s unreliable. 

KeithP

knightstyle said:

Diesels often take a short time before the starter starts in cold weather this allows the heaters to warm the combustion chamber and helps the diesel ignite.

But the OP has already told us it's petrol, not diesel.

brianposter

I once had a VW which started perfectly until I left it in a smart airport car park. When I came to collect it, it turned out that car park  staff had been unable to start the car and had had to push the car to the nearest available parking space.

I simply got in, started the car and drove off.

It eventually turned out that if you turned the key too far it cut out the starter circuit, so that the harder you tried, the less likely was the car to start..

Mistral001

As has been said it could be the starter motor that is sticking if there is a click when attempting to start.  Sometimes tapping the starter motor with the end of a brush shaft unsticks it, but I would see and Auto spark as it will probably need the starter motor replaced.  Not very expensive if they replace with a reconditioned starter motor.