[CSAGQ]

hey everyone
i had a issue with this couple months ago where my battery wasnt charging so i replaced the alternator and my battery was charging fine after that.
now since 2 weeks ago my battery has been going dead while the engine is running!
i checked the cables, fine. the light in the dash goes out and stays out once the engine is on (it is also completely out and not DIM)
heres the very annoying part of it the battery takes charge from a jump start and from a 240v battery charger! but not from the alternator!!
its driving me completely insane and cut my holiday short because i didnt want to be stranded!

could someone please give me a hand on how to properly troubleshoot this problem because no way in hell i can throw around cash to buy new battery and alternator here and there!
cheers!

 

[the evil twin]

Did you have the battery capacity tested on load? It's free and if the battery is cactus it will cause many of the issues you describe

 

[CSAGQ]

where can i go to get the battery tested for free?
can that really cause the battery to gain charge from everything BUT the alternator though?
cheers

 

[jimako]

First of all make sure you have a good clean and tight connections, Make sure the engine block has a good connection to the negative end of the battery.

Then start the engine and check the voltage output on the back of the alternator and on the battery terminals.
Then put the lights on and heater fan and check voltage again.
Then check the voltage as you hold about 2000 revs.

Let us know the results

 

[ITS A FORD NOT A NISSAN]

and check your fuseable link, should be near the positve terminal of the battery ( just behind)

 

[CSAGQ]

i thought that but i cant see how i could have blown it since i always remove the negative cable plus the light in the dash still comes on? they are in the same circuit?

will have a look and test everything in mornin

 

[CSAGQ]

battery on idle read 12.60v
battery reads 12.77v on 2000rpm
battery test shows 28% marginal so that needs to be replaced because it has been shot over time
but for some reason my alternator isnt putting out enough to even charge the battery and its brand new?
should i be looking to replace that aswell!?
cheers

 

[the evil twin]

Replace the shagged battery with either a new one or a known good and recheck the Alternator charge voltage 12.77 is too low as is 12.6 at idle but as stated previously the Alternator regulator can be tricked by dodgy batteries. You can't have dropped one phase of the Alt as it is a new one unless you are deadset unlucky and got a dodgy new Alt

You will never sort out what is wrong with the shagged battery in circuit... well, not 'never' but it will be much more difficult.

Once the battery is sorted look for dirty/corroded/frayed connections on the battery and earth cabling and to help fault finding... take a reading withe the Positive multimeter lead on the Battery + ve and...
1 the -ve lead on the -ve battery terminal
2 the -ve lead on a good chassis earth
3 the -ve lead on a good engine earth
and finally
4 the + ve lead on teh Alternator output and the - ve lead on the engine earth

 

[ITS A FORD NOT A NISSAN]

when it is running , try and get a voltage reading from the power output (large wire) from the rear of the alt, it should be a tad over 14 volts
other things to check
the wires to......
D+ on the rear of the alt should only get 12 volts when the ignition is on
S ( sense) should have 12 volts all the time , same as the main power out from the battery

 

[CSAGQ]

there is only 2 wires from the back of the alternator?
is the D+ the same as the output power?

 

[ITS A FORD NOT A NISSAN]

look a bit further down, there should be a larger wire , thats the wire that charges the battery

 

[ITS A FORD NOT A NISSAN]

D+ is for the dash light
S is to sense the battery voltage and it tells the alt how much power is needed , it is actually joined to the larger power wire comming from the alt

a good idea is to run another main wire for the alt output to the battery and also to run a smaller wire from the sense plug to the battery positive

 

[CSAGQ]

im deadset stumped here
i replaced the alternator myself and there was only 2 wires
1 small wire and another thicker wire coming from the plug
no other wire was on the old alternator that was replaced?

 

[ITS A FORD NOT A NISSAN]

that could be your problem?

can you take a pic of the rear of the alt?

one wire you have should be white with a red stripe ?
the other is just white and a little thicker ?

 

[CSAGQ]

yeh will take a pic now and post

but it was working all fine and charging battery for a bout a month after it was replaced?

 

[ITS A FORD NOT A NISSAN]

i dont know if it is possible, but maybe you were charging through the sense wire , and may have burnt out the sense part of the alt,

or you have a different alt installed, mine is a 93 td42 and i have 3 wires, 2 on a plug, and a larger one that is bolted to the alt

 

[CSAGQ]

could you take a pic of yours im having trouble connecting my iphone to the computer
there are 2 rogue wires that arent connected to anything and were like that before the alternator was replaced.. so maybe either of the 2 need to be connected??

 

[ITS A FORD NOT A NISSAN]

i will try

 

[ITS A FORD NOT A NISSAN]

now i have rewired mine so the colours will be different

the 2 top wires from factory should go to a plug ( mine are both red) factory should be one white with red stripe (D+) the other should be white and a little thicker ( sense)

the main power out just under them (i ran 2 thick red wires) factory should be a thick white wire that bolts to the alt, i have pulled the rubber boot back a bit so you can see the nut,

the thick white wire is still connected on mine but it has a black cover over it as seen running along with the red wires

 

[CSAGQ]

ahhk
thanks so much mate
only thing im concerned about is that spot exactly where you have the 2 charging wires bolted on is also where that little fuse/transformer (or whatever it is) was connected from out of the box