Page 1 of 1
Alternator - dodgy earth help needed!!!
Posted: Fri Jan 07, 2005 12:03 am
by porker914
I have had problems with the electrics in my 914 since I bought the car. I have added a new battery and when i run the engine the dial in the car reads about 14 volts although this is at cruising speed, its about 12 at tick over. Now when I turn on side lights only it drops to about 10V on eith tick over or at speed. When I turn on the main lights it drops lower still.
Can anyone say if this is just dodgy earths (i have rechecked a few before) or is it simply the alternator is failing? or even a regulator packed up.
please help!!!
David
Posted: Fri Jan 07, 2005 8:40 am
by impmad2000
If the alternator regulates at 14V with no electrical load, sound like the regulator is doing something, just can't do the current ! Side lights is very little extra current though. Is it just the lights that cause this, or heater blower, heater rear window, wipers too. Could be a fault in the side light circuit. It could be a dead diode in the rectifier pack, or worn brushes in the alternator too.
Have you verified the voltmeter reading with a test meter ? Sometimes dashboard meters can be mis-leading ....
To have a 4V drop, just by switching on the side lights, if it is a bad earth, you should be able to measure this. use a test meter and probe between earths. Battery -ve to chassis, Battery -ve to engine, Altrenator gnd to battery -ve, regulator gnd to battery -ve (and any other places you can think of).
Auto electricians should have a tester that checks out the charge system. I have seen a clip on meter that checks for charge circuit faults, never used one myself though....
Best of luck
Posted: Fri Jan 07, 2005 2:09 pm
by porker914
Tim
Cheers for the info I do have a volt meter but have yet to check what that reads. And yes basically any electrical device in the car causes some movement of the volt reading on the dash guage!!
Dont you just hate electrical faults!!
David
Posted: Mon Jan 10, 2005 5:30 pm
by Robster
Hi David,
for the record, my 914 shows 12 v at idle. The alternator starts charging at @ 2000 rpm, and then the volt meter shows 13.8v with no extra load. with full lights in this dips to about 11.5V, so I would suggest that you have a dodgy earth, or your lamp holders may be corroded. (don't forget to check the rear lights as well as the fronts.
Also check the volt drop with lights off, ie the heater fan , or indicators, etc. If this also shows a big volt drop (sub 10V), then it could be your battery earth strap between gearbox is knackered or has a bad contact with the body of the car.
Final thought, is check the connections at the battery are nice and tight.
Good luck!
Robster