ojw
03-28-2006, 05:09 PM
I have an intermittent problem with my 1991 520i auto, which goes a bit like this:
Occaisionally, when i try to start the car, it just clicks, or does nothing at all. When this happens, the trans program signal comes on. Sometimes i try it again straight away, and it starts fine. As soon as the car is running it drives really well.
So, i've had a look at the archives and it seems that a dodgy battery/charging system can contribute to this. So, i've just been outside to check the battery voltage - 10v with engine off, 13.9v with engine running. The 10v obviously indicates that the battery is shot, but i would like to know whether 13.9v is adequate from the alternator. I have read elsewhere on the forum that i should be seeing 14v, does such a small discrepancy make that much difference? Also, the car is more likely to fail me when it is warm than first thing in the morning, which would seem to contradict the low voltage theory. Is it possible that the fault is elsewhere and the low voltage is just another side effect?
If i was keeping the car i would just change the alternator, but i am selling the car so don't want to spend any money on it that is not going to help things. Equally i don't want to sell someone a dog, so would like to get this problem sorted if i can, as otherwise the car is spot on.
Meanwhile, if anybody is interested it's available for £500:D
Occaisionally, when i try to start the car, it just clicks, or does nothing at all. When this happens, the trans program signal comes on. Sometimes i try it again straight away, and it starts fine. As soon as the car is running it drives really well.
So, i've had a look at the archives and it seems that a dodgy battery/charging system can contribute to this. So, i've just been outside to check the battery voltage - 10v with engine off, 13.9v with engine running. The 10v obviously indicates that the battery is shot, but i would like to know whether 13.9v is adequate from the alternator. I have read elsewhere on the forum that i should be seeing 14v, does such a small discrepancy make that much difference? Also, the car is more likely to fail me when it is warm than first thing in the morning, which would seem to contradict the low voltage theory. Is it possible that the fault is elsewhere and the low voltage is just another side effect?
If i was keeping the car i would just change the alternator, but i am selling the car so don't want to spend any money on it that is not going to help things. Equally i don't want to sell someone a dog, so would like to get this problem sorted if i can, as otherwise the car is spot on.
Meanwhile, if anybody is interested it's available for £500:D