I need the communities help!

Are we sitting comfortably? Let me tell you a story.

Due to working from home, my wife & I decided to sell both our cars and I have been using my 1972 Fiat 500 R as my every day car; going to the shops, dropping kids off, driving to training, etc etc.

Over the last few weeks I have covered 100's of miles, the 500 R ( Bari ) has been great at eating up the miles and attracting smiles at every turn.

On the way back home last night ( travelled approx. 15 miles ) I was doing 40 mph according to Google Maps, and he cut out. No engine power and the lights turned off.

I pulled over into the entrance to a field, popped the bonnet and saw the + battery cable had come off. I put it back on, tightened it and expected Bari to start, and he never did and to go with it only half the lights worked.

So I started checking fuses, wiring looms, fuel pump, dizzy cap, all I could think to check with the limited tools I had.

It got to 20:30 and after approx. 50 minutes, I threw the towel in a called the AA.
The AA couldn't start it either and towed me home in the dark using inspection lamps as lights! Not great, but it worked and I didn't want to leave Bari over night.

So tonight I have had another look over Bari and still can't get him to start or the lights to work. I feel I have gone through everything but I'm obviously missing something, let me run down my list;

- Battery power level at 12.4v
- Earth strap ( battery and engine look good )
- Fuses good
- No obvious fried wiring
- Spark plug removed, got spark
- Engine turns over but does not fire
- Right hand head lamps and RH indicators work
- Left hand head lamps and indicators do not work
- All rear lights ( including indicators ) do not work
- Fuel level in fuel filter good
- Fuel pump works
- Fuel tank nearly full

What I am missing?

I have also gone through the 500 wiring diagrams to look for anything obvious.....can't see anything. Is there a hidden fuse that may have blown?

There is a curiosity though, on Bari (1972 Fiat 500 R ) I have a light relay next to the brake fluid reservoir and its not mentioned in manuals I have and I can't seem to find it on the usual spares websites.

All the wiring colours match the wiring diagram so I assumed the relay is a factory fit??

As I said, this is my daily drive and am hoping to use Bari again tomorrow afternoon.

Any help would be greatly received and I will buy you a virtual beer!

One problem at a time---you say that you have spark at the plug and plenty of fuel, but that it still wont start. As much as I hate the stuff, have you tried to see if the engine will start using 'easy-start' or such similar product (brake-cleaner works well, and is cheaper). Have you checked that the ignition-timing is correct? and that the tappet setting are correct? I realise that none of these suggestions will attend to the light (or rather,lack of), but I am trying to see if we can at least get the engine running. From your description, you would seem to have the all 4 of the items neccesary for combustion--air, fuel, spark and an ability to crank the engine.
The 'lights' problem needs some input from a member who either has a 500R or somebody who has a 500R wiring diagram squirreled away and can tell you what that relay is for.

Hi Hobbler,

thanks for the reply.
I have only had chance to be out in the garage for a few hours this weekend.
Here are the updates.....

1) I have tried easy start, no joy
2) looked again at the spark and now have NO SPARK
3) The reason for no lights, nearly all the light bulbs have blown

So I have just put the battery on trickle charge over night and tomorrow night I will start changing out the obvious electrical areas ( points, condenser, coil, swap over the fuses) just to try and find what's happened.

I have Googled the headlamp relay fitment and it seems to be an addition to either cheat a low rate switch or to upgrade bulbs.
The headlamp relay in question is also used by Alfa Romeo and Ferrari and I can't find it on any of the spares sites so opted for a modern replacement that arrives mid week.

Slowly but surely working my way through, plodding onwards.

Updates ( with hopeful progress ) to follow......

Toon500R said:

The reason for no lights, nearly all the light bulbs have blown

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That may just be a coincidence, but it might point in the direction of a faulty voltage regulator.

My dynamo generator has an output of 18volts before i switch to alternator !! Now blown lamps maybe indicate faulty generator that maybe has blown your ignition coil as well. I will suggest you to charge your battery or better use a booster or connect another car (always keep a spare car when you have a 500) for power and disconnect the generator output. After you start the engine (a spare coil might be necessary to have) you can check dynamo output and all the other electrical problems.

Peter might just have hit the nail on the head---whilst conceding to be no electrician, would a vastly overcharging alternater (due to faulty regulator) cause a current surge that could blow out the bulbs and fry the coil? Would appreciate an electrician clearing this query up!

Thanks all.

I have just ordered a new coil & voltage regulator.
I have a spare battery so no need to order that.

Hopefully all other items will start arriving in the next few days so slowly I will rebuild and test along the way.

I hope my new car turns up soon unless I'll have to use public transport, not easy from where I live!

Thanks again for the help and I'll keep those updates coming......

Toon500R said:

I have just ordered a new coil & voltage regulator.

Click to expand...

Good move but maybe a bit hasty.

It might have saved you a bit of potential frustration and money if you hung on for someone like our resident mega-expert electrical wizard Vitesse to give additional input....mine's just a hunch. Good luck.

If there is no power at the Coil when Ignition is turned on i put a temporary wire direct from Battery to Coil. If then it doesn't start it must be Coil or Ignition System you have.
Alan

Does a 500 R have an alternator or dynamo? If it’s an alternator then it has the little voltage regulator bolted to it which is probably solid state with a couple of diodes and resistors inside. I would expect that if that went faulty it would give 0 volts output rather than an over voltage that would cause things like bulbs to blow.

If it’s the old style relay voltage regulator, which I suspect it is? Then potentially what could have happened is because the battery positive lead fell off. Is the dynamo would still have been spinning at speed before the car came to a halt for a very brief time, this could have been sufficient enough to keep the cutout relay closed in the VR and it would have seen the battery output drop to zero and the dynamo and VR would produce a greater output to compensate this, as it sees the battery voltage to be below the dynamo output voltage. There is a red wire also connected to the same terminal on the VR as the output cable to the battery. This is what is known as the services output, I.e. it supplies the 12v for the services lights, ignition etc.... it goes up to the fuse box but is unprotected to the ignition, so as the ignition switch would have been on when the car stopped running suddenly, then the potential over voltage would have made it directly to the coil and of course to the lights if they were switched on?

It seems odd though as I would have expected the voltage regulator relay in the VR to limited the output (if it had been setup correctly) and also I would expect that it would only blow bulbs that were in use or switched on at the time? Again would that little over voltage fry a coil???? I would be surprised? Possibly the condenser would be more likely?

So I think you are on the right track ordering what you have done. The clue with most electrical faults is what has changed? In this case the positive lead fell off!!!

Vitesse said:

Does a 500 R have.............blah, blah, blah

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Amazing stuff, an even better answer than the comprehensive answer that I expected...the No-bell prize for services to Fiat 500 electrical problems is as good as yours.

Thanks for all the comments and inputs, very interesting, gives me more confidence to keep going and above all a MASSIVE help!

The generator is the original so assume dynamo?

Due to work ( and parts arrivals ) garage time has been limited.

Progress update.....

- I fitted all new bulbs
- All lights work EXCEPT headlamps
- Oddity is headlamps work on main beam, but not dipped
- I have ordered a new light switch ( just in case ) that should arrive soon
- I have made additional earth wires for the lights & fitted them ( something that was mentioned by another 500 owner ) that go from lights to main body Earth points
- New points & condenser fitted - still won't start
- New coil, voltage regulator still have not arrived, hopefully here by the weekend

Thanks again and any more ideas / pointers are very welcomed!

Have you put wire direct from Battery to Coil to eliminate problems in Circuit or Ignition Switch.
It's the first thing i always do.
Alan

Hi Alan, Not yet. I was going to wait for the new coil.
Do you think its worth doing that now or waiting?

Why not try it now only takes 10 minutes, nothing to loose
Alan

plasticpig1972 said:

Why not try it now only takes 10 minutes, nothing to loose
Alan

Click to expand...

So I have just had the first opportunity to try this and after a few attempts at starting ( with back firing and spluttering ) it works!

So now what? Is an a break in the wiring somewhere?