Battery/starting problems

[chris morley]

Unless the day is warm and dry - and unless I've used my car in the last 2 or 3 days - it just won't start
There is a repetitive click, click, click from the starter motor, but apparently not enough juice to turn it over
Whenever the starter is turned over it starts perfectly. Strangely, even 5 minutes on a battery charger is enough to solve the problem
I recently had battery and starter motor replaced but the problem remains
I'm told it's a common problem for non daily-drivers and I must keep the car constantly hooked up to a battery conditioner. Is this true?
I can't believe it would have been acceptable in the depths of a Bavarian winter

 

[John Maddox]

I would get all your earth straps checked for a high resistance as its unlikely to be a battery problem if it's new. Was it an OEM battery replacement with same cold crank capacity. I would also change the DME relay although it probably isn't this from your description. Put the full lights on and crank the starter- should dim but not go out. Then post results.

 

[Cater_Racer]

That's rubbish Chris, mine goes 7-10 days between usage and have no problems, check battery connections, if ok I suspect there's a leakage does the bonnet light go out when closed? Or have you been sold a sub-standard battery?

 

[A Ward]

Definitely check your earth straps - as John said in his reply. My brother had a similar problem with his for ages and had it permanently connected to a battery charger/conditioner - turned out that his earth strap was such high resistance that it may as well have not been there!! Don't be fooled by appearances either...his looked like it could have just come out the packet. Once renewed he had no problems whatsoever!

It may not be this - and I'm sure other people will have their own thoughts...but certainly my 993 is good for about 10 - 14 days without starting and still turns over ok.

Good luck - hope you get it sorted sooner rather than later.

 

[Robert Teague]

I run a c tec battery conditioner full time. if not and i should forget to plug in the car will sit for 10 days but not a fortnight.
Robert

 

[997GT3_KO]

I agree about checking that the bonnet light is going out when shut...

 

[Melv]

As above -964's also experience similar probs

There are quite a number of earthing straps -clean them up, especially the body to gearbox strap

Some alarm systems can also be a drain

My Cup hasn't been run for a month and started first time yesterday....

 

[Dylan1]

houston-you have a problem[]

 

[Porker993]

ORIGINAL: A Ward

my 993 is good for about 10 - 14 days without starting and still turns over ok.

Ditto

 

[davepaul993]

dme relays which company would you get one from for a spare ?
ive seen quiet a few out there but dont know which one to get.
do you have a part number and what cost was it.
tar 4 now.

 

[Jon Kent]

DME Relay part number is :-
993 615 227 01 (this replaced 993 615 227 00)

Recently discussed on a 964 forum, to which Bert Gear came back with the following (I've used Bert several times, never an issue!) :-
[FONT=comic sans ms"][FONT=comic sans ms"]
DME REALY 20.00 PLUS VAT

Bert Gear[FONT=tms rmn"][FONT=tms rmn"]
[FONT=tms rmn"][FONT=tms rmn"](independent Porsche parts supplier)[FONT=tms rmn"][FONT=tms rmn"]
buy on line at
www.PartsForPorsche.co.uk[FONT=tms rmn"][FONT=tms rmn"]
01271 866818[FONT=tms rmn"][FONT=tms rmn"]
[FONT=tms rmn"][FONT=tms rmn"]

 

[Stewart Rix]

Excuse my mechanical/electrical ignorance, but how would I "clean up" my earth strap? Do the terminals just get corroded? So would rubbing the connecting eyes with glasspaper do the job? My neighbour has a multimeter so I could check the resistance across the strap if I knew what I was doing.............

 

[chris morley]

Thanks for all the inputs guys!
Firstly the battery. My service guys - who know their stuff - put a hefty new Bosch unit in on grounds that the Porsche version isn't actually that great
I asked about earth straps and such but they drew a blank with them
I've checked the bonnet light and that goes out as it should

I think it could be the alarm draining the system but it doesn't seem to improve if I just lock it on the key or even leave unlocked

To me the really weird thing (and maybe this is a clue?) is that it takes literally 5 mins connected to a battery charger to sort it out. How weird is that?

 

[Mark Elder]

I think I'd be checking for something draining the battery by connecting a multi meter inline with the battery (obviously NOT switching on the ignition!) and looking to see what current is flowing. Then start pulling out fuses to see which one causes current to drop.

Somewhere on this 993 section is more detail on how to do this (including what the expected drain is with everything switched off and normal) - beware that for approx 20min after you switch off the ignition various things are (or could be) normally running - so not worth doing the test until all those have shut down.

 

[nfearn]

This is an odd one. Five minutes on a normal domestic battery charger isn't really enough to do anything of any consequence to the state of charge of the battery - is it a normal unit or one of the "fast-charge" type which push a high voltage through the battery?

Is the battery being disconnected from the car's positive connection when the charger is being used or just used with the battery fully connected?

Do you have an accurate voltmeter? If so, could you measure the voltage across the battery after it's been left for a while (the same length of time that you leave the car for between drives) but, importantly, disconnected from the car's positive connection. The voltage to the nearest 0.1V is needed.

Finally, when the car has started, how far and how long is it driven for typically before being put away again?

If you could respond to the above we can perhaps start looking to eliminate some possibilities and home in on the root cause.

regards
Nick

 

[chris morley]

Thanks Nick, I'd appreciate your opinion
The charger does have a fast and a normal setting and I use fast if it won't start
But I've started wondering if it could simply be the 5 minutes wait rather than being on charge? In other words just leaving the car and coming back to it might rectify the problem.
Did I imagine it or did I read somewhere there can be different affects in the starting sequence eg. if you press the dimple on the fob when the key is in the ignition rather than using it to unlock the doors and turning the key straight away?
Recently, since I've been locking the doors on the key rather than the alarm I've noticed a less forceful 'clunk' from the door locks when I disengage
Currently I don't own an amp meter but I can get one if it helps solve the mystery. I was even thinking of getting a 'start monkey' to keep in the boot but i don't think they can cope with big batteries

 

[nfearn]

Chris

I've no idea about the use of the alarm fob and its effect on starting - mine has an aftermarket alarm and immobiliser.

I think the first step will be to get yourself an automotive-type multimeter. Something like this should be fine: Draper 78997 Autoranging Digital Multimeter (you can find them on Amazon and so on). If the car is only driven infrequently (say, less than once a week) and then only for short distances (less than 50 miles) you would also benefit from a trickle charger - something like this: Draper 63147 Battery Master
(Amazon again).

If your use profile is as described above, it's fairly likely that your battery is never fully charged (a 50 mile trip will certainly not fully charge the battery) so simply having the battery fully charged may solve your problem.

Anyway, if you could obtain the multimeter as a minimum we can start looking for the specifics of the problem.

 

[chris morley]

Your assumed use profile is pretty accurate Nick. This is very much a cherished third car rather than a workhorse. I just imagined they all are by now? One problem is I don't have a garage so it's out every night. Which also presents trickle-charge problems given the lack of outside power
On occasions where I've found it very flat I'd run an extension through the front door and put it on 'normal' charge overnight, but average trips are much less than 50m. I'm doing about 4-5k pa
One thing I'm trying to do is just use it more often. Daily use presents no starting problems. But then if I'm away one or two weeks I suspect it gets drained completely again and never really catches up unless I remember to overnight it.
I've owned the car for close to 8 years though and things definitely seem worse lately. Hence the battery/starter replacements
I'll track down those two items on Amazon and try to get to the bottom of it. It would certainly add greatly to my enjoyment of the car if I could rely on it to start!

 

[nfearn]

Hmmm - sounds very like a very partially charged battery. Let me know once you have the multimeter and we'll go from there.

 

[chris morley]

OK Nick, the Draper stuff has arrived
At this point I should probably confess I'd never heard of a multimeter until this one arrived in my bikeshed- please make any instructions childproof!