is it the generator?

nwymbs · #1 (**permalink**) 07-10-2007, 06:56 PM

Hello Alfa Wizards -

I need your help, please!

I think my generator is bad but remain hesitant to replace it without a definitive test first. Is there a sure-fire method? The main symptom I have is that after driving for a couple days/week for a month it refuses to start. Then its off to pepboys to get a replacement battery (for free). Time to change this pattern!

Also, does anyone have a source for the trunk pan for a 63 Spider? I originally thought the battery problem was related to having a slightly rusty trunk, but I've cleaned this quite well. Sadly, it remains a possibility...

Cheers
Nick

**pathung** · #2 (**permalink**) 07-10-2007, 08:45 PM

I wonder if Wolf Steel would have an entire trunk pan? Worth a try.

**AlfaDuc** · #3 (**permalink**) 07-11-2007, 05:51 AM

Quote:

Originally Posted by pathung

I wonder if Wolf Steel would have an entire trunk pan? Worth a try.

nwymbs · #4 (**permalink**) 07-11-2007, 06:08 AM

excellent, wolf steel looks great - and they have a location in VT which might help with the shipping.

gdimassa · #5 (**permalink**) 07-11-2007, 06:11 AM

firstly... the generator lamp is on or off?

**AlfaDuc** · #6 (**permalink**) 07-11-2007, 06:20 AM

Quote:

Originally Posted by gdimassa

firstly... the generator lamp is on or off?

**Peter** · #7 (**permalink**) 07-11-2007, 07:48 AM

There are basically threee things that must be in place. A working generator, a working voltage regulator and an intact wiring circuit, including the generator light....you need that light to be able to charge the battery. Does the light come on when you turn the key before starting? That at least tells you the bulb is OK. If the generator light is off when the engine runs, next thing you want to do is still measure the voltage at the battery. See if there's a difference whether the engine is running or not. You should have at least around 13.8 volts when the engine runs, it maybe a little above idle. So check your wiring, then your voltage regulator, and exchanging the generator would be last, it's the most expensive part. There are companies that can check your generator for you though.

gdimassa · #8 (**permalink**) 07-11-2007, 12:27 PM

another simple test, that doesn't need any instrumentation is:
start the engine and with the light off detach one battery cable, if the engine continue to run... then the charging circuit is OK, otherwise, if the engine stop, is there a charging problem.
I dont think that the trunk pan could cause a bad charge of the battery... if it let flow hte starting current, it must let flow also the charging one.

phila3885 · #9 (**permalink**) 07-13-2007, 08:02 AM

I agree if the generator is good you may have a small drain on the battery when the car sits (light bulb? aftermarket stereo system? some other non-standard electronics?). There are companies that sell battery disconnect switches that mount on the battery and simply twist on/off to disconnect the battery without having to remove the battery cable. I have one on my M3.

101 Alfa Mike · #10 (**permalink**) 07-13-2007, 08:13 AM

If it passes all of the above tests, then check the points inside the regulator. Severely corroded/pitted points will reduce that potential 30 amp output from the generator to a mere trickle.

nwymbs · #11 (**permalink**) 07-17-2007, 08:13 AM

wow - thanks for the help!

I'm out of town right now but I'll follow up on my progress when I get back.

I have a spare voltage regulator. How do I tell if the existing one is not working properly?

For the record, the wiring on the car is a bit off. The previous owner installed an after-market stereo which I have removed along with all the related wiring. Since then, I have most of the essential electrical items working except for some of the lights inside the gauges. This includes the generator light as well as the oil/water lights and the backlights for viewing at night. I assumed the generator light malfunctioned because of a bad ground/wiring because it fails to light when the key is turned.

Also of note, the car came with a Monit charge gauge. The deflection of the meter is inconsistent when the car is running, sometimes showing a charge and sometimes not. Of course, I can't be 100% sure it works properly but thought it would be worth mentioning.

Nick

**Peter** · #12 (**permalink**) 07-17-2007, 10:29 AM

if your generator light is not working, that's where I'd start. You need an always hot wire on one spade, and the green or blue wire from your voltage regulator on the other.

gdimassa · #13 (**permalink**) 07-17-2007, 04:41 PM

Quote:

sometimes showing a charge and sometimes not