STARTING PROBLEMS

[Deleted]

Hi Guys,

I recently bought my MK11 coupe & the seller advised that the battery was shot & he had been isolating it after each use so I immediately replaced it 2 weeks ago.

Following a day at a show last Sunday I parked it up without isolating it & today its as flat as a pancake. Can anyone advise what it might be & what I should say when I take it to get looked at? I am totally useless with anything (really!!!) so would appreciate any advice, also should I take it to a garage or a specialist electrical outlet?

Many Thanks, Michael.

[Phil Nottingham]

Welcome to P5 ownership and this forum. The battery may well be shot - go to a reputable battery retailer who can test is properly. New ones 55A/h are redaily available but they are much smaller but remember these cars are POSITIVE earth unless converted

However if it was necessary to isolate it before it suggests a current drain as opposed to a battery fault. This will not be the clock unless it is faulty (disconnect it) but could be a faulty courtest light switch. Test these operate properly in the door posts. Then remove the A1 fuse under the twn fuse holder box under the bonnet this will discoonect all battery operated circuits except the horns.

It could be faulty dynamo/regulator and an old time auto electrician can test these and adjust recondition as necessary.

It could also be faulty wiring - the rubber/fbaric covering is now well past its use by dates and previous owners mods and "repairs" may well be faulty. It is alwys a good idea anyway to fit a battery isolator as it is a useful theft deterrent

Whether you intend to DIY or get someone else to do a factory workshop manual is essential and I aslo suggest you join the club as local members may be able to help/point you in right direction. These cars are excellent classics but as with all cars of that time must have regular attention so as to be reliable and may parts can be mended rather replaced so do not bother with modern garagees unless they know how to service old cars as they are not suitable for most modern trained "mechanics"

Let us know how you get on please and good luck - tell us more about your car and location etc

[stantondavies]

Always difficult to add to Phil's advice, but this definitely points to something draining the battery and isolating circuits by removing fuses is the way forward. Not being an auto electrician I would take them all out and return them one at a time, checking the battery voltage with a meter every few days. Eventually the fault should show up.
I don't think that a faulty dynamo is THE cause though it might contribute to the problem. For years the battery on my car used to go flat over a period of months. Eventually, 10 years ago, I found that increasing the voltage at the regulator to 14.5 volts solved the problem, and I am still running on the same battery.
Fitting a battery isolator switch has been an aspiration of mine for many years but I've just not got round to doing it. I've looked at dis-car-nect which seems an excellent product, but I am not sure how practical it is to fit to a P5. Is there room for it under the battery cover? And what a pain it would be to use it as an anti-theft device if you have to open the boot and remove the battery cover every time one wants to use the car. And in the event of a short circuit or electrical fire, it is hardly an instant disconnection.
Has anyone fitted such a device and how have you done it? Strikes me that something around the driver's seat area or under the bonnet might be possibilities.

[Phil Nottingham]

Dynamo cars can discharge the battery if the cut-out/regulator is faulty. Leave this till last as tampering with this is not a good idea. As it is a Mk2 there is are only 2 fuses + overdrive!

I have alwys toyed with this since I fitted one on my P2 on the rear seat cushion frame/rest which can be reached from the driver seat as the batery is under it and not as esay to get to quickly with big seat cushion and floor to lift up.

There is room under the battery cover but the main battery cable runs on the passenger side on 3 Litre so the lead to the starter soleonoid could easily be diverted to a battery switch on the bulkhead/A panel and a new short lead then run from the switch to solenoid - on a V8 a similar arrangement could be done but the switch can realy only go on the A panel and the main lead would have to be shortened and a much longer new lead used

[Deleted]

Thanks for all the advice guys, I have found an auto electrics specialist locally who stock spares for older vehicles & having spoken to them they have said that they should be able to investigate & sort out the problem easily so fingers crossed.

The car is a lovely 1965 MK 11 auto coupe EUO ***C & it has a red switch on the metal battery cover to isolate the battery (I must admit I probably assumed that all P5's had them!!!).

This aside its great & I can't wait to get some use out of it starting with a trip up from Devon to Cheshire at the end of this month.

Cheers, Michael.