Intermittent failure to start

[reds]

Hi all, wondering if anyone has had a similar issue, as even the garage are stumped on this one.

Car died a couple of weeks ago, after a 45 minute journey. I was able to bump start it, and drive it 45 minutes home, tried to turn it over when I got back, and it was dead, just a click nothing else, left it overnight, and again wouldn't go, so had it towed to local garage

Garage replaced a blown fuse, and said this had fixed the issue.

Drove for 1 hour, left for 2, turned over no issues, and drove home again

Drove 20 minutes later that week, turned over no issues, then drove for 5 minutes, DEAD. Managed to bump start it again and drive back to garage (20 minutes) 

Left at garage for few days, they checked all the earths and for any faults, and said they had come to move it 2 or 3 times over the period and it started everytime without an issue.

So drove for 1 hours yeaterday, left for 2, started with no issues. Drove 20 minutes, stopped for petrol, DEAD, had to jump start it. Drove for 5 minutes, and then left it to charge for 2 hours, and it turned over no issues again.

Drove for 1 hour. Turned it off. Tried to turn it on again, DEAD. If i jostle the key forward and backwards 10 times or so, it got the engine going (without the jump pack on) 

Left it overnight (14 hours) and turned over with no issues this morning !

[Sol]

Either a bad ignition switch I'd say, or a failing battery. Also could be intermittent charging by the alternator, resulting in that some times it will charge the battery and other times it doesn't, resulting in it running down on some journeys and not on others.

I'd start with checking the state of charge from the alternator and test the deep current ability of the battery (most Kwik Fits have a battery heavy discharge tester) and if those check out ok, I would suspect a bad ignition switch.

[cancunia]

Faulty starter relay?

[Sol]

Yep, that crossed my mind too. Normally if a booster pack or jump does the trick, its a bad battery but an intermittent fault on the ignition or starter could just decide to work at the instant you jump it.

[GraemeT]

Faulty starter relay?

If this is always when it's hot then google 'heat soak starter relay' - had that once.