dubnut 10 Posted February 1, 2012 hi all... having a problem with starting the car... wouldn't start yesterday battery was flat...got a good battery and ran ok wouldn't start again today..went with bump...drove to work and it wouldn't start at home time. got 13.8 v on battery when car is running any ideas ???? many thanks in advance Scott Quote Share this post Link to post Share on other sites
vw domo 0 Posted February 1, 2012 does it turn over? or do you get nothing when you turn the key? Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 1, 2012 tries to turn over just seems like no power in battery after i got home..i left it for 30 mins and starts fine but i just know it won't in the morning and six o'clock with alarm blaring is not appreciated by my neighbours...lol i can only think of earth problem but dint know now to check Quote Share this post Link to post Share on other sites
RW1 0 Posted February 1, 2012 Your battery is whacked. When you start the volts drop, if they drop too far, the ignition stops working. The reason why it starts later is cos the compression is lower due to cooling off. So the starter current demand is not as bad and so the battery voltage does not drop below the ignition low volts limit where it ceases working. Thats why the good battery started it. If once started, putting on the old battery and starting gives it less load and so the volts stay up enough. To check its not an earth problem, compare across the battery terminals and then do across the battery +ve to the alternator earth. The reading should be very similar. . Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 1, 2012 its still doing it with the good battery...the old one is off the car ????? will try earth tomorrow too dark now Quote Share this post Link to post Share on other sites
vw domo 0 Posted February 1, 2012 lol oh dear. probably a drain then, i had this problem when i first got mine and i got so fed up i called an auto electrician out in the end, not cheep but worth it! The cables under the air box had worn through and where earthing on the chassis. check the voltage in the morning if you can and see if its low. to stop it draining just disconnect the battery before you go to bed and reconnect it in the morning for the moment. The way to find a drain is to use a multimeter across the battery without the engine running and see if the voltage slowly drops off, you may have to sit for a while. if it does work your way from the battery disconnecting wires till the voltage stops dropping (or pay someone to do it lol) Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 1, 2012 thank you muchly....will.attack tomorrow..gonna take battery off for tonight Quote Share this post Link to post Share on other sites
Wullie 1 Posted February 1, 2012 Quick way to check for battery drain is to disconnect the battery lead and then connect a test bulb between the lead and the battery terminal. If there is no abnormal drain the bulb will just about glow. Anything more and the bulb will glow brightly. Pull one fuse at a time till the bulb goes out and it will show you which circuit is causing the problem. Then comes the hard bit finding out just exactly where in the circuit the problem is. At least you can leave the fuse out to stop the drain. Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 1, 2012 thanks any special bulb ? Quote Share this post Link to post Share on other sites
Wullie 1 Posted February 1, 2012 I used a spare indicator bulb. Soldered a couple of wires to it, long enough to place the bulb in the car beside the fusebox. Any change in the light brightness was easily noticeable and gave a bit of light at the scene of operations as it were. Quote Share this post Link to post Share on other sites
vw domo 0 Posted February 1, 2012 I used a spare indicator bulb. Soldered a couple of wires to it, long enough to place the bulb in the car beside the fusebox. Any change in the light brightness was easily noticeable and gave a bit of light at the scene of operations as it were. Thats a good idea mate! Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 2, 2012 which battery lead..i guess positive ---------- Post added at 05:26 PM ---------- Previous post was at 04:20 PM ---------- lol....ignore above post...comments sense kicked in hopefully sorted now...thanks guys will try to start it later.. it was headlight wires by airbox i think Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 3, 2012 still done it this morning aarrgghh back to square one horn kept sounding when i turned the key this time ???? maybe time to change cars :-(:-(:-( Quote Share this post Link to post Share on other sites
vw domo 0 Posted February 3, 2012 Dont give up, how many wires have you got coming off the positie terminal on the battery? it wont be the headlight wires as they wont draw current untill swiched on. a comman one is check the boot light isnt staying in when you close the boot. Quote Share this post Link to post Share on other sites
dubnut 10 Posted February 3, 2012 update..... yesterday i did the bulb job and had a bright light which dimmed when h/l fuse removed....bingo... or so i thought as having recent h/l issue seemed logical moved wires from under air box did bulb test..great job left it four hours and started bang on. took her out for twenty mins. parked up left it overnight..about seven hours and no go again :-( bulb test today...no dim light until alarm starts and its bright could it be the alarm ??? can't turn it off.how hard to unwire sorry for the essay Quote Share this post Link to post Share on other sites
vw domo 0 Posted February 4, 2012 (edited) If you can, bridge a multimeter across the live from the battery and set it to mili amps. Then turn on the alarm and take a reading and post it up on here, imo anything above 10mili amps is too high. if its not drawing too much current then get a new battery. If it is drawing alot of current check the alam wires, there should be a controle box in the drivers footwell and the horn in the engine bay, if the wires are good then get a new alarm or just rip it out. hope you get it sorted mate, good luck. Edited February 4, 2012 by vw domo had a thought Quote Share this post Link to post Share on other sites
