starting issues

[unsheenashashin]

Morning all.

58 plate pd TDI owner. While back, battery drained while I was on holiday. Got it going, but have an airbag warning light on my dash. For a while, it was hesitant to start, till one day during winter it wouldn't start at all. I went and got a new battery, everything was fine.

Until recently.

Back to being hesitant to start again, got worse over the last week. Ended up having to bump start it. I've been switching the auto lights off at night, in case that was draining the battery, I can't think of anything else that could be. This morning as I was trying to start it, flashed up an engine management workshop warning on the mfd.

Anyone got any ideas? Surely it can't be the battery, thing's brand new. Starter motor maybe? It's had the injector recall done, so I don't think it could be related to that.

 

[Speed-FReek]

Have you had it scanned for fault codes? If not then get that done first.

 

[Muttley]

I'm assuming that you mean you changed the battery in the last few months i.e. the winter just past.

Even a new battery can fail, for instance by a mechanical failure of the plates in the cells, partially shorting out one or more cells.

A simple test is to measure the open circuit voltage of your battery (take off the connections before you test the battery) when fully charged - it should be 12.65 volts. If it is much lower than that then the battery is on its way out. A fully charged battery that only shows 12.0 V open circuit is definitely almost dead.

The place where you got the battery should be able to do a full load test on it, which will show if the battery can deliver the current needed to start the car (usually this is the hardest task a battery has to perform). If there was any kind of guarantee on the battery it would be worth looking out your receipt in case it is still within its warranty period.

One other thing you can do is to check the connections to the battery and all of the earth straps which connect the engine to the body. A bad connection or an earth strap starting to fray will limit the current that the battery can supply.

 

[unsheenashashin]

Bumping my own thread

Spoke to a couple of mechanic mates, it's going into a garage on Thursday (just started a new job so that's the first chance I've had) could it be related to glow plugs or the cold start circuit? It seems to start when it's a bit warmer. If I have to bump start it, it idles higher than normal, for longer than I'd expect it to. Is there a separate fuse for the cold start?