[carlsworth]

Hey yall

I have a problem with alternator not charging...

The alternator has been bench tested and outputs 14v
battery tests at 12.6v
The ground is fine
the live has been tested to the back of alternator and has 12.6v
the plug for the dash/exciter shows 12.08 in one pin, and the other pin shows 12.22

so in theory, everything seems to be working...
so why isnt my alternator charging the battery???

Desperately need some help here

Cheers

Carl

 

[Swobber]

Not working.

You need at least 13v output when the car is running at idle.
13.,5 - 14,2 is common for most cars.

 

[carlsworth]

yeah, I know its not working, but which bit isnt working???

The alternator shows 14v when tested off the car
so why would it not charge the battery???

 

[Cris]

yeah, I know its not working, but which bit isnt working???

The alternator shows 14v when tested off the car
so why would it not charge the battery???

You need to follow it. What does the alternator produce when it's on the car. If you are seeing 14v at the alternator (on the car) then go from there and test each stage in the loom until you track down the problem. Could easily be a damaged wire.

 

[carlsworth]

ok
cleaned up the live to alternator
getting 13.4 now - at idle

while running, I put the mutli meter on the battery, and getting 13.00 and seems to be going slowly up

is 13.4 enough from the alternator???

 

[freakazoid3]

yes

 

[Brains]

ok
cleaned up the live to alternator
getting 13.4 now - at idle

while running, I put the mutli meter on the battery, and getting 13.00 and seems to be going slowly up

is 13.4 enough from the alternator???

I would say 13.4 at idle is alright but at 2k rpm I would consider below 13.9 to be bad depending on what electrical equipment you are using.

 

[carlsworth]

ok chaps

I wired the mutli meter to the battery, so i could see what its doing in the car, and went for a little drive

So, when starting the ign the battery is at 12.6, then on crank it dropped to 10.5, and as soon as the car started, it went back up to 12.6

When driving, the car jumps around a bit between 12.0 and 12.4,(I also tried with fans/heater on) and when stopped in traffic, the most it got up to was 12.5

What the hell?

Its not dropping anymore, which WAS the problem - it would drop to below 12, and cause the HICAS light to come on and the steering to go wonky- I have a feeling that if I went out for longer, it would probably happen again

 

[freakazoid3]

bad earthing?

 

[Brains]

It's not charging at all with that voltage. But usually you can drive quite a bit without the voltage dropping.
Keep driving for a while and it will drop more and more until the car dies and the battery is drained.

 

[Brains]

Does your battery light work? It should be light up until you've started the car.
If the light is broken or the wiring is damaged the alternator won't charge.

 

[carlsworth]

yes mate, the battery light comes on and stays on until the car is started, then it goes straight off..

does the alternator have a fuse or relay or something that may be down?

 

[carlsworth]

only getting 12.5 from (LIVE WIRE) at back of alternator now

 

[Cris]

only getting 12.5 from (LIVE WIRE) at back of alternator now

If that is you literally touching the alternator sounds like the alternator is at fault.

When all is well and the engine is running you should be seeing 13.5-14v everywhere.

A fit battery should be 12.5-13v when the engine is off. If it's still at that level when the engine is running it isn't charging.

My usual reaction with electrical gremlins is bad earths. It could be that the alternator's earth is at fault (if you are saying that the alternator is fine off the car). Perhaps try a new earth, if it's an R32 and the battery is still in the front you could run a cable to the negative post on the battery for testing purposes.

 

[Brains]

If that is you literally touching the alternator sounds like the alternator is at fault.

When all is well and the engine is running you should be seeing 13.5-14v everywhere.

A fit battery should be 12.5-13v when the engine is off. If it's still at that level when the engine is running it isn't charging.

My usual reaction with electrical gremlins is bad earths. It could be that the alternator's earth is at fault (if you are saying that the alternator is fine off the car). Perhaps try a new earth, if it's an R32 and the battery is still in the front you could run a cable to the negative post on the battery for testing purposes.

Easiest if you have a jumper cable laying around. Use it as an earth cable and see if it helps.

 

[carlsworth]

tried the earth straight to alternator-
No difference

There's not a fuse or link somewhere that could be at fault??
Spent last night stripping the loom from the battery to the alternator to find any breaks- seems fine
Spoke to scott at abbey motorsport, and he reckons the alternator is ****ed...
So, before I
a) pull out all of my hair
b) go on a gta5 stlye murderous rampage
c) cry until my eyes fall out

Im going to try another alternator to rule it out

any other ideas?

 

[carlsworth]

dammit
Im phoning round for an alternator, and the part number is coming back as 70amp, not 90amp

part number on alternator is

23100 86l11
A2T35891

which cross references as Nissan Pathfinder or X Trail
but states 70 amp instead of 90amp

Is this going to work on my car, or is it just too low???

 

[matt j]

Have you checked to see if the charge signal works, there's a 2 pin plug on the alternator which if not working won't charge.

 

[carlsworth]

all wires from the car give battery strength signal

at a bit of a loss with this now- car has been stranded for nearly 2 weeks because of the f ing alternator - time to by a reliable new car

 

[carlsworth]

Thnaks to everyone for help and suggestions

It was a dodgy wire behind the light cluster
grrrrrrrrrrr