D21 Alternator

[Mikel]

Hi guys,

I have just changed the alternator in my ute d21 2.7l disel 4x4.

I replaced it because I thought it was broken as when starting the car voltage was 12.4

Now new alternator does the same, but I just realised that voltage goes to 13.9v when acelerating, idle the car. Is that normal? Or should be 13.9v also with out accelerating just by starting the car?

 

[tweak'e]

it should be 13.9 at idle.
not sure what set up you would have as i don't have the book on D21's, but common problem is wrong alternator warning light bulb. especially if people fit led's.
later version may have the D22 style dash, i can't recall if it applies, where they have resistors/diode on the back of the dash cluster which can fail.

 

[Mikel]

it should be 13.9 at idle.
not sure what set up you would have as i don't have the book on D21's, but common problem is wrong alternator warning light bulb. especially if people fit led's.
later version may have the D22 style dash, i can't recall if it applies, where they have resistors/diode on the back of the dash cluster which can fail.

When acelerating goes to 13.9, but idle 12.4v

it should be 13.9 at idle.
not sure what set up you would have as i don't have the book on D21's, but common problem is wrong alternator warning light bulb. especially if people fit led's.
later version may have the D22 style dash, i can't recall if it applies, where they have resistors/diode on the back of the dash cluster which can fail.

It is a 1995 model there is no warning lights

 

[tweak'e]

It is a 1995 model there is no warning lights

that sounds very odd. sure its not the furthest right hand light of the centre group? got a pic of the dash?
maybe the bulb has blown. that certainly would cause charging issues.

 

[Mal B]

Hi guys,

I have just changed the alternator in my ute d21 2.7l disel 4x4.

I replaced it because I thought it was broken as when starting the car voltage was 12.4

Now new alternator does the same, but I just realised that voltage goes to 13.9v when acelerating, idle the car. Is that normal? Or should be 13.9v also with out accelerating just by starting the car?

G'day Mikel,
If you're saying that voltage drops to 12.4 when you're using the starter motor, I would think that's fine considering the load you're putting on the battery.
A good battery should show 12.5 to 13.7 volts after sitting overnight, and while charging voltages can reach 14.4 volts +/- 0.2v.
If the ute starts in the morning, shows about 12.5volts or better in the morning and over 13.5volts when running your alternator is fine.
Cheers
Mal