batteies and car stating issues ( electical)

[rishi]

ok guys if your car ever decides to not start:

1. is it making a clicky noise , is the lights flashing , instrument panel lighting up, and radio comming on, but the engines not turning on.

2. this normally means soemthings up with your battery, to check your battery open up your boot, then on the right hand side lift the black panel up under neath it is the battery undo the bolt above to expose your battery under than should be a little hole check what colour it is , red, black , and green i think. if its green batteies fine, if black needs charging and should be fine, red means its gone( maybe yelloe cant rember) this is for the orginal bmw battery not on all other brands such as my bosch replacement.

2.this is the easiest and most liekly cause. if your car wont start check this first, try jump starting or possibly charging your car up, thats pretty simple just huse the jumping cables to connect your bonnet turminal red thingy, and then the black on to an earthing part look for a nut near the red one. do the same for the donor car or your charging machine. start either one up leave for like 30 secs then try starting your car.

4. if this works all is good drive around abit . stop and start check all is working . leave it over night and check again. if it needs changing ie the battery s dead again it should mean yoour batterys on it way out. get it replaced should be around 80 120 pounds depending on brand and how nice your stealership is if you want oem.

5. more complicated but possible, if you have one of thoose multimeters get it out. go to the rear or your cr expose the battery and set it to measure volts and put the red bit to the postive and black to negative , you should read 12v. this means your battery is about right voltage wise.

6. now if the problem with the car is more sinister turn on your engine if you can ( jump start if needed), after a while with it on got back to the battery whiel on and do the same test with the mulitmeter again .

7. soemthing sinister could be the alternator when you do the aformentioned test you should read 13v.... soemthish

if its lower and equal to 12v it means the alternator isnt charging the the battery . heres where my expertise ends go to a mech get the part changed. try findign the relavant part your self its often cheaper than buying from mechanic but compare the market dependign on your cheapness levels

8. ok now if none of the above helps you may have a parastic drain occuring . does your car die over night even after a full charge/ jump start. your probabyl haev this problem. wihich could be invasive. now what i recomend you do is switch your multi meter to amps no go to the battery in the boot, car off lock your doors manually if neesasry, onyl your two boot lights should still be on. to turn these off get a screw driver or pen, put it in the latch on the boot lid ie where the bolt would be . this should lock onto your pen. and fool your car into thinking its closed. lights should go off.

9. ok now put red to +ve and black to -ve on amps mode. you can place it on straight away but its best to write down what readign you get. wait at least 10 mins to be safe , and take a reading. this will tell you hwo much current ( amps) is ebign drained whiel dormant. you have to wait a while since it takes a few mins for the car to rest.

10. your reading should be around 0.03 amps aroudn that. thats very low. on my car it stayed at around 3 amps i think at least 10 tiems the normal rate. ok so if your is above 0.03 i belive your battery is being draiend by somethign thats either shorted out or goen wrong.

11. a possible cause coudl be if you installed any ice/ head units, go to an auto electrican and explain your findings and say you haev installed a new head unit recently and ask if they can check it for any power drainage when the cars off. also try checkign any new wiring angel eyes that fade can also do this im told( i think most brits will have the ones that plug into the side lights so these should be fine since they are turned off with a switch)

12. ok in my case it wasnt any of the above. and to put it i was ****ing my self lol. ok now start your car if you can turn on you air conditionign to full blast. leave for 30 secs, now turn everything off including interior lights wait a whiel longer then check to see if your fans are on at all. in my case it was very unnoticable unless you put your hand on a evnt. it has been documented. that another sign ( not symptom) you could see is erratic behaviour in your ac unit ie, little speed / temp control.

13. if this is the case a part called the final stage resistor has gone bad. this part is a tad bit difficult to access if your a newbie like me. but if you dotn think you would be able to change it go to a garage they onyl charged me 25 quid so it wasnt too bad. heres a few diys if your upto it courtesy of the yank at e46fantics.com

14.http://forum.e46fanatics.com/showthread.php?t=256286&highlight=final+stage+resistor+diy

scroll down a few posts. double check but mine was done from the drivers footwell and mines an 316 dunno if that changes anything

15. now if you want to save some cash do it yourself, take your time and youll be fine. this took my mechanic only 5 mins to get it out.

16. to save more you can buy the part yourself. try ebay search for final stage resistor i saw one for £44.80 delivered

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?Vie...A:IT&ih=018

try euro car parts that where i got mine they £50+vat so around 58 quid

now you can try this auto shop thast also online they were the cheapest one i could find and although i didnt buy it from them it was only becuase i couldnt wait 1 extra day for delivery.

http://www.c3bmw.co.uk/

17. this once fitted should allow complete control over your ac and check for any parasitc drain just incase. but only change this part if your ac stays on / is acting erratically.

18.ok if you havent found your problem yet it could have soemthing to do with fuel pumps etc ie no clicky noise, and so ends my knowledge currently. if you have problems starting and you suspect a parasitic drain buts its not the ac/ radio, then it could be one of the other numerous elctrical systems in your car. this is long and ardouous work( i cant spell or type so i apologise for that in advanced) my rac gezza tells me that it would involve having one person in the car with fuse box open and another at the battery with the multi meter connected to the battery at amps setting. then the car must be fooled into thinking its locked again ( pen method) doors closed/ locked manually( to avoid alarm going off) pull a fuse and measure any change in amps at the back then put it in and try the next one. a sa i said very long. it may be best to let an auto electrican take over. but this will help you narrow down the area of the drain.

lastly dont jump start from the back ever ( damages ecu) and if your in doubt let a pro do it. and observe

and if you cant do anything straight after jumping and you got a parasitic leak disconect you battery and lock up manually that way youll be able to drive it the day after.

hope this helps ill edit the mistakes later because im a bit busy atm , sry for the poor post and good luck guys/ gals

pm me if you need advice

[MattBMW]

nice little write up man must have took you a good hour!

About the batteries though on mine (factory) the colours were:

Green = good

Black = not sufficiently charged or battery is on its way out.

Red = Knackered

I believe though normally is Green, yellow, Red again mor or less meaning the same thing

[MashupMark]

nice little write up man must have took you a good hour!

About the batteries though on mine (factory) the colours were:

Green = good

Black = not sufficiently charged or battery is on its way out.

Red = Knackered

I believe though normally is Green, yellow, Red again mor or less meaning the same thing

Yeah mine was:

Green = Good

Yellow = Needs charging / Check battery

Black = its f**ked!