Had a similar problem on a Kia Picanto 2009 where it would occasionally turn over but fail to start. It could occur several times in a row and then go a week without occurring.
After searching the internet, others were reporting that it can be related to the immobiliser aerial that picks up the signal from the key and is situated in the bezel surrounding the lock that has "LOCK ACC ON START PUSH" printed on it.
I noticed that on turning the ignition that if the immobilizer light (car with key symbol inside on bottom right of dashboard) did not come on, then the car would turn over but not start.
I removed the antenna (see https://www.youtube.com/watch?v=lK67Ii0UUVk
) contacts and speculatively rubbed down them with fine grit paper. It was not possible to access the other half of the mating connector to inspect it. It has been back together three weeks now and has started every time. In the meantime I've ordered a replacement to try if it fails again. I struggle to appreciate how a coil of wire in the bezel with two flying leads could fail though.
Its manufacturer's part number is 9544017050 and available off eBay from Korea for around 15. It seems to be used on Hyundai cars too.
The thread below on a different forum suggests that it is best to solder the connection, but I am a bit dubious about some of the assertions in the thread.
I hope this information may be useful to others with the same symptoms in diagnosing the cause of their problem.
Wednesday, August 9th, 2017 AT 3:45 PM