I have a 78 Spider. Was driving it this summer, top down, enjoying all that a classic Itallian sports car can offer, when, all of a sudden, BANG!!. A large pop sound, like a major fuse or some other component blew, all guages dropped to 0's, and I was only able to coast to the side of the road. Finally have it back in my posession and plan to get it running again by spring, but have no idea what could have happened. I have power to the starter motor, headlights, and radio, but not much else. No spark at the coil. When it was running I know I was overcharging the battery some due to a bad voltage regulator, but this had never been a big problem, at least for a few thousand miles. Has anyone had a similar event happen, or have any idea where I should start looking? I am pretty good at fixing things, but horrible at diagnosing. Any info is greatly appreciated.

Mark

Sounds like you have fried your ignition circuit. There are some major relays in the fuse box i bet have blown. Check these out. Also check you are getting power out of the alternator[regulator could off blown] to ignition switch. Just start at starter motor and check for continuity to all electrical ignition wires. Fuse box is first port of call as you have no power to Dash etc. Do not run with overcharging [alternator regulator] as it can cause an electrical fire!!

Andy.

Yea, I figured I was pushing my luck with the regulator, but it worked for so long I figured all I had to do was deal with the sulfer smell. I guess you learn things the hard way sometimes.

That is where I will begin to look. I see a lot of parts available on Ebay, and have dealt with International Auto Parts a time or two as well. Hope to be able to look at it a while this Sunday.

Thanks for your info.

Mark

:bang:

I am having trouble with my 1980 fiat (did a search of forum on 'voltage regulator' and got this thread...

First off, this thread talks about the suspicion that the voltage regulator was causing the battery to overcharge as evidenced by the sulfer (I suppose in the battery box). I also have this problem but I think it is actually from the battery being overloaded because it is not charging (my voltage test read about 11.5 volts at terminals with lights and heater fan on - should be 12 - 14 volts) so the battery is running the car with little help from the alternator. Do you folks agree with this theory?

Second, back to my problem...so my battery is throwing out electrolyte turning into sulfer in battery box and the lights are dim and turn signals funky. Like I said, battery voltage test not up to spec. I take out voltage regulator and clean up - no help. Here is the potentially bad part - I take out alternator and take apart and inspect/clean up. It did have rust on the rotor and stator that I sanded off with a fine sandpaper (tell me if this was not a good idea). The slip rings are grooved but seem to be ok. Voltage reg brushes still seem to contact slip rings. Cleaned up all terminals and put back into car. Now car makes buzzing noise when trying to start...will not even turn over.

Have a new voltage reg on order from IAP.

Oh, by the way, the battery light does not come on w/ignition key in ready mode which I think inicates a bad voltage reg.

Any help would be appreciated. I will report back on progress once I put in the new voltage reg. Thanks.

Jim

jimd said:

Oh, by the way, the battery light does not come on w/ignition key in ready mode which I think inicates a bad voltage reg.

Any help would be appreciated. I will report back on progress once I put in the new voltage reg. Thanks.

Jim

Click to expand...

The alternator needs to get an initial excitation current via the battery charge indicator light connected to terminal D+ or 67 of the alternator.

If the bulb filament is blown or any of the associated wiring is damaged or disconnected, the alternator will not start charging.

Check the bulb and wiring. Below is the alternator wiring diagram for the 1980 Spider.
.

Thank you for your help so far...

I bought and installed a new electronic voltage reg from IAP and now the battery indicator light comes on but unfortunately I still get nothing when I try to start the car. I must have either done something to screw up the alternator or maybe have a connection wrong to the alternator (D?) terminal but that is so simple I can't see how I screwed that up...it only has 2 connections - one that goes to the starter and the other to the wiring harness (ignition switch I suppose?), these are insulated from the alternator housing by a plastic washer. There is also a small wire that has a female receptacle that slips over a male spade so that is simple and not a problem.

I think I must have messed up the alternator when I took it apart and cleaned it up...do you think that I created a short? Is there a way to test for that? Probably should have left well-enough alone...

Actually the 2 connectors (one to the starter, other to the wiring harness) are attached to the B terminal. The D is the one with the spade. I have the alternator off and disassembled again. I don't understand why I get 140 ohms from the B terminal to the heat sink which of course is connected with 3 screws to the alternator housing and thus get 140 ohms from B to the housing because of that. Is that normal?

jimd said:

I bought and installed a new electronic voltage reg from IAP and now the battery indicator light comes

Click to expand...

Did you fit a standard replacement internal regulator to the alternator or a general purpose external one?

jimd said:

I still get nothing when I try to start the car.

Click to expand...

If you mean the starter motor doesn't turn an/or the car doesn't start, then the battery is probably flat becasue the alternator wasn't charging before and the car has now been left for a week. Try jump leads from another car or a substitute battery.

If that's not the case. What happens and/or what do you hear when trying to start the car?

jimd said:

I think I must have messed up the alternator when I took it apart and cleaned it up...do you think that I created a short? Is there a way to test for that? Probably should have left well-enough alone...

Click to expand...

There's no way to full test the alternaror without spinning it to about 1000 rpm. You can check the warning light circuit within the alternator by disconnecting the wire from the "D" terminal and connecting a normal 12v 5W filament bulb (not an LED) between the battery (if charged) 12v +ve terminal and the alternator "D" terminal. The bulb should light if the circuit is OK.

Thank you very much for your help Davren...but you will not believe this...

I figured I had no choice but to take the alternator out again and disassemble it to see if I broke something internally or what-have-you. Couldn't see anything obvious. Ran the same tests on the rotor and diodes as before and got the same results. Put it back together (in answer to your question, the voltage reg that I bought from IAP is a new style electronic type, not the original replacement). Put the alternator back in, hooked up the terminals as before, re-connected battery and presto, the car starts. Ran it for a while, shut it down and restarted ok. Checked the battery voltage w/lights and heater on and got the required 14 so the voltage reg did need replacement. Too tired and mentally exhausted to go for a ride...will leave that for another day. I have no idea what the problem could have been as I swear I put it all back the same way. Hopefully the car will cooperate. Sorry for the mystery. Thanks again.

"All's well that ends well" (WS)