07 Focus starting fault

[Mark jones]

Hi, new to the forum and looking for help with a starting fault on my 2007 2.0 tdci Focus. Little bit of history firstly, it's had a battery, alternator and starter motor. Some mornings it starts fine, others it doesn't turn over as fast and won't fire, I've also noticed on dark mornings when it fails to start the headlights come on while I'm cranking it? As soon as I put a set of jump leads on, it fires ok?

Anyone come across this fault before?

[artscot79]

it could be you're glow plugs which should have been tested or a current drain on the battery .unless the battery had a fault a free test should have ruled that out a starter motor is also not so common and again a simple test would have proved the alternator was fine so first off what battery is in it is it a ford one silver calcium or a lead battery if its a lead one theres you're first issue is the battery the correct cca for the car diesels are usually higher cca so 500 or more next what I you're cranking voltage a dad test when you first try to start the car will show you anything below 12.5v is a problem next with the dash test start the car scroll through the menu to batt it should read 14v or higher if not and its higher than 14.4 or lower than 14v you have an issue it sounds like you have a drain or battery or charging issue if you have auto lights again this is why they are coming on

despite having new batt etc if the garage wasn't ford or aren't familiar with smart charge etc they will replace with the wrong parts

[Mark jones]

Thanks for the quick reply. It's a strange one, it will start fine for a week or so then not start. The crank speed and tone is different and the battery only lasts a couple of cranks when it fails to start. As mentioned before, the headlights come on even though the auto light switch is turned off. As soon as you put jump leads on it fires straight away, also the headlights don't come on with jump leads connected.

[james1089]

Could try leaving battery connections off and see if it starts fine for a week, if all ok maybe check heater plug relay.

[artscot79]

the lights are the key here with auto iff they shouldn't be coming on suggesting that even though the switch I off a relay ir sensor is permenantly on or intermittently on I don't know enough about the auto lights and how it all links to say for sure but I think its the culprit