V8V 4.3 laboured start

[nsjb]

Hi all, i drive my Vantage about once a week and just lately, although the car starts, it doesn’t have that usual roar of revs before settling down to its usual idle. Instead it starts and then a few seconds later the revs pick up and it eventually sounds normal. Subsequent starts in the day are fine and it seems fine to drive. It has a new battery but I did need to jump start it a few weeks ago (which prompted the new battery) and it laboured to start then too. Any ideas?

[TheRainMaker]

The first thing I would do is make sure the battery is 100% charged and go from there

[nsjb]

Thanks. It is a new battery but I suppose there could be an issue making it discharge a little during the week of no driving.

[andyvvc]

Was the new battery fully charged? Might be worth buying a Ctek or similar battery maintainer and seeing if its any better after a full charge? (Or just take it for a 60 minute drive)

[krisdelta]

I wouldn’t count on a new battery being charged - 100% pop it on the conditioner until it’s in peak condition.

[Riddochg]

I see you have a 4.3, same as me. The early ones have a battery cutoff switch. Swaps everything into low power mode to conserve the battery.

If you have it on yours you will find a button behind a panel on the right hand side of the boot. That puts it to sleep. A button behind the drivers seat wakes it up. Great way to save the battery.

[chunkster-deluxe]

If it’s not the battery, maybe it’s the fuel system problem shown in the below redpants video? The check valve had failed, meaning fuel pressure had to rebuild from zero when starting.

https://youtu.be/8jiTRZkI63I

[nsjb]

Thanks for all your replies guys. I drive it once a week for 2x45 min trips to and from work. When I get home surely the battery will be fully charged? It makes me wonder if it is discharging somehow. But I’ll try and find a battery charger so I can rule it in or out of the equation.

[krisdelta]

It’s not impossible the alternator or belt that drives it are sub optimal, but a conditioner will tell you if the battery is ok, or not, and these cars are very battery sensitive.

[Minglar]

It’s been covered in depth elsewhere on here but a faulty tracker unit can cause a battery drain. That could be worth checking as when the unit fails it can cause all sorts of electrical issues which usually result in a rapid battery drain too. Good luck. I hope you find a solution to your problem.

Best Regards

Minglar

[LTP]

nsjb said:

Thanks for all your replies guys. I drive it once a week for 2x45 min trips to and from work. When I get home surely the battery will be fully charged? It makes me wonder if it is discharging somehow. But I’ll try and find a battery charger so I can rule it in or out of the equation.

I think it depends on the type of journey. 45 mins at motorway speeds with no stopping and the lights off then yes, I'd expect the battery to be charged. 45 minutes of stop-start and crawling on an urban single-carriageway, with the lights and a seat heater on, then no, I wouldn't expect the battery to be fully charged.

The only other comment I'd make is I have read that the early alarm/immobilisers were prone to fail and, as well as generating spurious signals that can upset the car's electronics, can flatten the battery. As your car is a 4.3 then, if you still have an immobiliser, I think you will have the early system so it may be worth getting that checked. I the meantime a battery conditioner should keep the battery topped up, even against the drain of a faulty immobiliser.