1970 Fiat Spider not Charging

[JohnD]

Hi,

My Dad has a 1970 fiat spider with a 1800cc motor. The car is not charging. He had the alternator rebuilt and purchased a "good" used voltage regulator. Between the both of us we have about 5 used voltage regulators and even with the rebuilt alternator and swapping out the voltage regulators it is still charging with 12.5 volts at the battery while idling. Is there anything else in that could be affecting the volage regulator or alternator? In other words, what else could we change to fix the problem? Any thoughts would be appreicated!

John D. Nicosia
1971 1608 Spider
2012 Fiat 500c

[majicwrench]

Gotta quit just changing stuff. Is regulator getting power?? IS charge light on in tach??
Keith

[azruss]

a 70s style regulator with a low idle will deliver that kind of voltage. what is more important is if you raise the RPMs to 1500-2500, what is the voltage to the battery. The regulators have points inside, the gap to these points can be adjusted to increase or decrease charging voltage.

[JohnD]

Gotta quit just changing stuff. Is regulator getting power?? IS charge light on in tach??
Keith

We have been systemically checking each voltage regulator combined with a newly rebuilt alternator. We have tested it at idle and at higher RPM. The red light stays on. My Dad has owned the car since 1979 and rebuilt everything (owned a shop) in 1980. The car has never behaved this way. Anything else that we may be missing? Also, we were recently told that the voltage regulator must match the manufacturer of the alternator. Does this make sense?


Thanks again and look forward to all replies!

John D. Nicosia

[azruss]

is there a possibility that your current alternator has a built in voltage regulator and you have 2 of them.

[JohnD]

is there a possibility that your current alternator has a built in voltage regulator and you have 2 of them.

I am pretty sure it does not but I will confirm.

Thanks,

JDN

[majicwrench]

OK, you gotta check to see if you are getting voltage to the regulator. It comes from one of the fuses at the end of the fuse block ( sorry, don't recall which end, aint gonna look it up) if fuse is blown OR not making good contact idiot light will come on and car will not charge. YOu need to see why system not working and not just change parts over and over. Simple system.

CHECK THE VOLTAGE AT THE REGULATOR TERMINALS KEY ON ENGINE OFF

[JohnD]

OK, you gotta check to see if you are getting voltage to the regulator. It comes from one of the fuses at the end of the fuse block ( sorry, don't recall which end, aint gonna look it up) if fuse is blown OR not making good contact idiot light will come on and car will not charge. YOu need to see why system not working and not just change parts over and over. Simple system.

CHECK THE VOLTAGE AT THE REGULATOR TERMINALS KEY ON ENGINE OFF

Thanks Keith,

We will check tomorrow. But I guess you answered my question where at this point blown fuse or fuse contact could be the "only" other issue to check, right? I am pretty sure voltage was checked to the regulator but I am not sure if it was with the key off. I will post an update.

JDN

[majicwrench]

No point checking voltage key off. Read previous email KEY ON --ENGINE OFF.
Never said anything about it being the "only" other issue to check. Could be dozens of diff things. But first CHECK VOLTAGE AT REGULATOR THE BROWN WIRE KEY ON ENGINE OFF

[JohnD]

No point checking voltage key off. Read previous email KEY ON --ENGINE OFF.
Never said anything about it being the "only" other issue to check. Could be dozens of diff things. But first CHECK VOLTAGE AT REGULATOR THE BROWN WIRE KEY ON ENGINE OFF

Tried what you suggested. It appears that the fuse get "very hot" while the car is running. We are going to check it out. I will post when the problem is solved.

Thanks all for your help!

[RRoller123]

The spring pressure on the fuse holders is weak to begin with and they can get bent back a little when changing and that will result in a loose fuse and a high resistance connection, causing heat. I had a loose one that looked fine, ohmed out ok, circuit didn't work. Pulled fuse, bent the fuse holder tabs in a little to make a tighter fit, circuit worked.

[JohnD]

The spring pressure on the fuse holders is weak to begin with and they can get bent back a little when changing and that will result in a loose fuse and a high resistance connection, causing heat. I had a lose one that looked fine, ohmed out ok, circuit didn't work. Pulled fuse, bent the fuse holder tabs in a little to make a tighter fit, circuit worked.

Awesome thanks!

[mdrburchette]

You might want to check the alternator light relay and the exciter wire to make sure everything is connected and in working order.

[JohnD]

You might want to check the alternator light relay and the exciter wire to make sure everything is connected and in working order.

Well, it turned out to be a defective relay. Thanks everyone for your help!