Starting issue mk5 golf petrol

[golfmk5gt]

Hi guys. Iv got a 2005 golf gt 2.0 fsi. If it’s been sitting for 12 hours it’s a bit slow to start. If I leave it for 24 hours it won’t start. Just keeps turning over until the battery goes flat sometimes splutters like it’s trying to start but no joy. I can hear the fuel pump priming but it won’t start. It’s fine when it’s running. It’s worth noting that when I jump start it, it turns over a bit faster and it starts straight away. Is it possibly the battery? Or a fuel pump issue? Any help will be greatly appreciated

[WxmDaggers]

Do the headlights work ok? This is sometimes a sign of a flat battery. If the battery's fine it could be the starter relay. Have you plugged a code reader in to see if anything comes up?

Sent from my H8216 using Tapatalk

[Rob69]

It sounds like the battery is struggling to hold a charge, can you check battery voltage with a voltmeter before cranking and immediately after cranking? It should be around 12.5V before and recover quickly after cranking, with the engine running you should see around 14 - 14.5v across the battery terminals. Some garages will do a free 'drop test' on the battery then try to sell you a new one.

[Crasher]

I would change the battery, modern starters are so efficient they will crank over on a battery that does not have sufficient voltage to operate the engine management, this often confuses people more used to the old fashioned symptoms of a flat battery.

[golfmk5gt]

Thanks guys, I’m buying a new battery and a starter relay tomorrow, gsf doing 60% at the moment and il get back to you and let you know how it goes. The car has a few little issues but I bought it for less than a grand with 100k miles. I want to work on it my self to learn a thing or 2