Alternator only chargers when revved up a couple of times

Hello c3owners!

So i got a Citroen C3 1.4 HDI 16V 2004. Last days i had low car battery problems (abs, airbag lights appear and disappear while driving, especially in low speeds and when turning, and permanent battery light). I bought a charger and i charged the battery all night and it seemed to recover.
I tested the battery voltage with a multimeter, i get 12.30V when car is not running and i got around 12.00 to 12.20 when motor is running, even if i turn on lights, radio etc. and run 20km to 30km normally. I was expecting the alternator to give me around 14V to 14.5V.

The only way i get this values is when i revved up a couple of times for 2/3 seconds until i got the 14.5V. After i reach the 14.5V, the voltage is maintained +- constant until i turn off the engine and let the voltage drop to the 12V.

First, could it be just the battery getting old?
Second, if its the alternator, is there any way to fix the alternator output, without replacing it for a new one (i dont know the steps or if its too hard to switch with a new one) to give the +-14V without needing to revvup to 6000+rpm every time i start the car?
Best regards,
Rui de Lima

rukadesigns wrote: ↑Tue Jan 29, 2019 7:46 pm Hello c3owners!

So i got a Citroen C3 1.4 HDI 16V 2004. Last days i had low car battery problems (abs, airbag lights appear and disappear while driving, especially in low speeds and when turning, and permanent battery light). I bought a charger and i charged the battery all night and it seemed to recover.
I tested the battery voltage with a multimeter, i get 12.30V when car is not running and i got around 12.00 to 12.20 when motor is running, even if i turn on lights, radio etc. and run 20km to 30km normally. I was expecting the alternator to give me around 14V to 14.5V.


The only way i get this values is when i revved up a couple of times for 2/3 seconds until i got the 14.5V. After i reach the 14.5V, the voltage is maintained +- constant until i turn off the engine and let the voltage drop to the 12V.

First, could it be just the battery getting old?
Second, if its the alternator, is there any way to fix the alternator output, without replacing it for a new one (i dont know the steps or if its too hard to switch with a new one) to give the +-14V without needing to revvup to 6000+rpm every time i start the car?
Best regards,
Rui de Lima

Hi

I don't see this a specific to a diesel fuel. The petrol models have an alternator too.

Your alternator needs to have the regulator replaced and it is best to change the alternator for a complete new one and fit a new alternator belt at the same time.

If you want to know the steps for alternator replacement and those sorts of jobs, you need a Haynes manual for the C3. It is invaluable for these sorts of jobs.