Alternator

[BRUN]

right, is my alternator about to die ?

when i use my leccy windows, the lights on the dash dim, and unless im drivin im pretty sure my headlights do aswell

is this normal ?

ive got a Halfords Calcium battery thats about 10 months old now

 

[p carr]

try the earths sonds like a bad one

 

[BRUN]

if it is buggered, is there any others that will fit that are better ?

like one off a 16v/Willy maybe ?

 

[BRUN]

anyone help me out here ?

 

[BRUN]

oh, my present alternator is a reconditioned one which has been on a few months, how can u actually tell if its not runnin to full potential ?

p.s. cheers p carr my car is goin the garage on thursday for rear brakes so ill get him to check the earth out

 

[Rajk]

check the condition of the battery, charge or get halfords to check it. If you are loosing charge it could well be your alternator. Also listen for noise from the alternator when the car is on, I can only describe it as flappy type noise. a friends 16v needs doing and it makes a flappy noise. hope this helps because some garages may say there is something wrong when there is not, to make money.

 

[Alex M]

Get a volt meter (a multimeter is ideal) and connect it across the battery. Ith everything off iut should be at least 12.6 volts. Watch the voltage as you crank her, it will drop but should still stay at least above 11v. Now with her running with nothing on you should see the voltage rise quickly and should be high 12v, low 13v anyway. Put on a pile of electrics, lights, heater, stereo and see if the alternator is managing to keep the voltage across the battery high, (should be still 12.5-13 odd volts). If it aint alternator (or at least the regulator) is on its way out. Also get a free test done on your battery from a garage or autostore and see if it is dead. Checking your earths is not a bad idea either. Dont know if that helps you.



Alex M

 

[BRUN]

it does Alex, a lot, cheers mate

 

[BRUN]

hi mate i got some numbers now

ignition off - 12.5v

ignition on - 13.5v

stuff on - 13.5v

so this means its running ok ?

i had my headlights on main beam, the blowers on hot and on full, and my HU and Snooper on

 

[Alex M]

The ignition on value, is this with enginer running, I assume so since it is higher. Your alternator is kicking out charge alright but I suspect there a possible problem with the regultor which is part of the rectifing circuit in the alternator. My mates car does this, but is still going strong on the same alternator. Would not worry overtly as it will simply go like this until it packs in, which when it happens will be obvious, unless it is really doing your head in just leave it. It might be worth checking you aux belt maybe it is slipping a little and check alternator connection, but I am fairly sure it is the voltage regulator.



Alex M

 

[Alex M]

By the way if it is only happening at idle (low engine revs) then definetly dont worry about it.



Alex M

 

[BRUN]

cheers Alex, car is goin the garage tomorrow to check out the rear brakes and hand brake cable, and also possible strip/rebuild of the front calipers, so ill ask him to tighten the alternator and check the connections

 

[lofty]

want to buy my Alternator from a 16v? not sure about fitting, there is a fair bit of adjustment on them?

can post?

 

[BRUN]

im not sure it would fit lofty, if it would then im interested as im sure it would be a more powerful one

however, at the moment i need to keep what little money i have for a diagnostic next week, and most likely new rear brakes tomorrow

stay in touch though, if it will fit and u still have it in a few weeks ill have it

 

[lofty]

no worries mate,

ni idea if it will fit but anything can be bodged, just some easier than others, all it does is run off the belt and produce leccy!

 

[BRUN]

yea i know, but the fitment to the engine might be different

 

[BRUN]

ive checked the voltages again today

this time i managed to watch the voltages from in the car

12.5 with ignition off, when starting this drops quite a lot, i think it might have actually gone down to 10 but id have to have another check

now this time when i did it, and put everything on, my revs were always below the idle point when the voltage was dropping, or low

could someone tell me what this regulator does, i think its possible its been causing the problem ive been having

 

[Alex M]

A good way of telling if your regulator is on its way out is at low idle the lights on the dash will fluctuate slightly in thier brightness at a quick tempo, it usually dissappears when revs rise a little. If the voltage drops significantly when cranking then it is a sign that battery is not producing enough cranking current and is struggling. If voltage rises quickly when running even with things on, then alternator is fine. Its always hard to diagnose theses things from afar, but I wonder if your battery is past its best. Get a free check on the battery from kwik fit or someone like that. The lights would dim when you switch another item on as thier is always an assosciated voltage drop when something else is added to drawing from a battery. Check the battery and then you will be able to concentrate on the alternator, but if it aint broke dont fix it, if you know what I mean. You could also put an ammeter wired in line with the battery to see what current the alternator is chucking out, which can then be compared with book values, but it is a hassle to do on an impermanent basis. Cheers for message I hadnt played about with the private message thing yet. Give us a shout if this is unclear, as I tend to ramble in circles when I get going with the typing



Alex M

 

[BRUN]

how slight is this fluctuation, ill have a check later mate when it gets a bit darker so i can tell

what do you mean by cranking ?

my battery should be fine as its not that old, its a Halfords Calcium one, i do have an amp though

 

[BRUN]

well i just had a look mate and i cant see any fluctuation, it all seems perfectly stable to me, the only way i can get the lights to dim is by pressing the electric windows

im gonna get the belt tightened up, as i forgot to have it done the other week

 

[Alex M]

It is possible there is nothing wrong with it, my own dim a little when I do my windows also, just wait till it does go and then the solution will present itself. When I say cranking I mean turning over on starter but not actually running (take coil lead off if it starts too quickly too get a reading) if voltage drops a huge amount when it is turning over on starter i.e. below 11 anyway (at first , obviously not after turning the starter for ages) then it is struggling. Let us know how you get on with it.



Alex M

 

[BRUN]

hi Alex, i bought a Gunson start check, and ive done all the checks and my cars battery and alternator seem fine

it is ever so slightly undercharging with everything on, but i had to stick a lot of things on for it to do that

so, guess its fine

 

[Alex M]

Thats cool if it aint broke dont fix it



Alex M