reluctant starting - electrical

ChrisG · 20-03-11, 05:31 PM

OK
Had the problem to some degree last year- and just been to start the 80 Sport that has been under wraps in its garage since mid December.

i)Connected battery, new last summer - voltmeter reading about 12+ volts.
ii)Turned key, engine turns over, almost at 'normal' cranking speed then, within a couple of seconds slows down - as though the battery is flat. At this point the volts are reading low.... possibly 8-9 volts.
iii)solenoid is then clicking in and out furiously
iv) connect jump leads, engine turns over, normal cranking speed, and after about 5 secs engine fires up.

Once running you can turn it off and restart on the battery, after a few minutes, or several hours.

This was a problem earlier last year and as the battery was 10 years old I treated it to a new one --so symptoms have been similar with two batteries , an old and a new.

Possible that this is a faulty battery??? (Seems to hold its charge ok).

Bad electrical connection somewhere between battery,solenoid,starter ???
Seems to have started, possibly, after new gearbox mounts were fitted - coincidence??

As always, thanks in advance for suggestions

oh and I reeaally enjoyed the 15 miles I did in it this afternoon....

vag80 · 20-03-11, 05:42 PM

Chris i would say the battery has a duff cell, if the car jump starts ok and starts ok then after i would say the wiring is ok,if the wiring was at fault it still wouldn't start with a jump

mikes2 · 20-03-11, 05:44 PM

I'd suspect the starter is pulling too much current and dragging the battery down.

May just need the starter stripped and serviced or the solenoid could be the cuplrit

BIGGYIN · 20-03-11, 05:45 PM

Maybe,battery?
Could you borrow a third battery and see if that solves the problem?Then if it's not the battery,the fun begins.

ChrisG · 20-03-11, 06:59 PM

Quote:

Originally Posted by vag80

if the wiring was at fault it still wouldn't start with a jump

yes I couldn't get my head around that either !

Quote:

Originally Posted by mikes2

I'd suspect the starter is pulling too much current and dragging the battery down.

May just need the starter stripped and serviced or the solenoid could be the cuplrit

I'm not a great electrician but from my physics lessons at school ( long time ago -!) I was sure that it was a current issues - when not using the actual starter motor the volts seem ok-ish perhaps a tad low but running the engine results in 13+ volts showing on the voltmeter in the car.
Had great results doing this with 6volt Beetles in my youth

Clean up the commutator, every connector, and wayhey....

Quote:

Originally Posted by BIGGYIN

Maybe,battery?
Could you borrow a third battery and see if that solves the problem?Then if it's not the battery,the fun begins.

umm I'll have to see, most of the other easily avaiable batteries are on recent cars and they seem not to like having the juice removed

I'll test the battery tomorrow and if necessary I'll just take it back, it is under warranty.
I can strip the items, just rather not have to.....still longer daylight hours and warmer weather now.

Thanks guys !

Megsy · 20-03-11, 08:09 PM

Has the battery been on constant charge or left disconnected? just wondering as batterys wont last as long in this state as one that is on a running car used every day.

JMLAudi · 20-03-11, 09:23 PM

Hi

Just a thought...........check and clean the engine to body earthstrap connections
as well as the battery to bodt strap
posible corrision in the body to engine earth strap, or battery to earth cable( greenish powder under plastic insulation)........will need replacing

my 2 cents

cheers
john

Rickman · 20-03-11, 10:16 PM

what make battery did you put on when you bought new? Not a banner battery I hope....

Tim C · 20-03-11, 10:44 PM

Could be any or a combination of all the point mentioned. Duff battery, lazy starter or dodgey connection.

If you are jumping it from another running car, the 13-14 volts that is produced from a charging alternator can be enough to overcome the latter 2 reasons. Similarly, a weakness in a battery will be hightlighted by the latter.

A process of elimination I'm afraid. Although as it restarts after a short period of time it would point towards the battery. Having had a quick recharge from the alternator it's OK , but it decays away after a while. You could try leaving it on a charger and then see what happens.

As well as the battery and earth strap connections it could be the starter motor connection. Or even the bare conductor that links from the solenoid to the starter motor itself, mine eventually vapourised on the quattro. As it gets gradually thinner through corrosion, it becomes too thin to carry the current and then acts like a fuse wire

.

rickytractors · 20-03-11, 11:22 PM

Hi
i get this sort of problem at work every day that i have my own drop tester and 9 out of 10 time it's the battery and at £120 a pop you have to get it right. if i was you take the battery to a tyre company/garage and get them to do a drop test, this will tell you is the battery is duff. I would also start at the battery and go all the way to the starter motor and clean all the terminals. The machines i work on with engine running i get 14 volts, engine of and get 12 volts some times when doing a crank start test i will get 6/7 volts, on the drop test if you get below 9 volts then change battery dead cell this will charge ok but will be no good to start the engine.

20-03-11, 05:42 PM	#2
vag80 Senior Member Classic Audi Club Member Join Date: Oct 2008 Location: Bracknell Posts: 1,967	Chris i would say the battery has a duff cell, if the car jump starts ok and starts ok then after i would say the wiring is ok,if the wiring was at fault it still wouldn't start with a jump __________________ nothing like a bit of deep dish 200k club member 87-b3 80 83-4000 2 door

20-03-11, 05:44 PM	#3
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	I'd suspect the starter is pulling too much current and dragging the battery down. May just need the starter stripped and serviced or the solenoid could be the cuplrit __________________ 1991 90 quattro 20v sport 1991 90 quattro

20-03-11, 05:45 PM	#4
BIGGYIN 4 ring whore! Classic Audi Club Member Join Date: Mar 2009 Location: Merseyside Posts: 7,976	Maybe,battery? Could you borrow a third battery and see if that solves the problem?Then if it's not the battery,the fun begins. __________________ q90 B2 Type 85 - q90 B2 Type 85-PROJECT-ABY 20vt KARL. Injection is nice but I'd rather be blown

20-03-11, 10:44 PM	#9
Tim C Senior Member Classic Audi Club Member Join Date: Aug 2009 Location: Poole, Dorset, England Posts: 1,729	Could be any or a combination of all the point mentioned. Duff battery, lazy starter or dodgey connection. If you are jumping it from another running car, the 13-14 volts that is produced from a charging alternator can be enough to overcome the latter 2 reasons. Similarly, a weakness in a battery will be hightlighted by the latter. A process of elimination I'm afraid. Although as it restarts after a short period of time it would point towards the battery. Having had a quick recharge from the alternator it's OK , but it decays away after a while. You could try leaving it on a charger and then see what happens. As well as the battery and earth strap connections it could be the starter motor connection. Or even the bare conductor that links from the solenoid to the starter motor itself, mine eventually vapourised on the quattro. As it gets gradually thinner through corrosion, it becomes too thin to carry the current and then acts like a fuse wire . __________________ quattro RR - crystal silver quattro WR - 1981 Lombard RAC rally recreation (50% share) Nissan Navara - tow car / service vehicle for above A4 2.0T quattro s-line special edition - wife's http://www.flickr.com/photos/37654549@N06/sets/

20-03-11, 08:09 PM	#6
Megsy Grown up member Classic Audi Club Member Join Date: Feb 2008 Location: cheshire Posts: 229	Has the battery been on constant charge or left disconnected? just wondering as batterys wont last as long in this state as one that is on a running car used every day.

20-03-11, 09:23 PM	#7
JMLAudi Grown up member Classic Audi Club Member Join Date: Jan 2010 Location: Knaresborough/Shipley Posts: 951	Hi Just a thought...........check and clean the engine to body earthstrap connections as well as the battery to bodt strap posible corrision in the body to engine earth strap, or battery to earth cable( greenish powder under plastic insulation)........will need replacing my 2 cents cheers john

20-03-11, 10:16 PM	#8
Rickman Grown up member Join Date: Feb 2010 Location: South Cumbria Posts: 122	what make battery did you put on when you bought new? Not a banner battery I hope....

20-03-11, 11:22 PM	#10
rickytractors Grown up member Join Date: Nov 2009 Location: chatteris Posts: 141	Hi i get this sort of problem at work every day that i have my own drop tester and 9 out of 10 time it's the battery and at £120 a pop you have to get it right. if i was you take the battery to a tyre company/garage and get them to do a drop test, this will tell you is the battery is duff. I would also start at the battery and go all the way to the starter motor and clean all the terminals. The machines i work on with engine running i get 14 volts, engine of and get 12 volts some times when doing a crank start test i will get 6/7 volts, on the drop test if you get below 9 volts then change battery dead cell this will charge ok but will be no good to start the engine.