I have just bought a non runner Fiat 500 with a 126 engine fitted. I am currently going through the ignition system to try and get it started - i t has sat for 6 years in a garage.

I have replaced the spark plugs, leads, distributor cap, rotor arm, points, condenser and coil. I replaced the condenser on the side of the distributor.

It still wont start.

However, i have noticed that there is a second condenser fitted to the coil - to the positive terminal i.e the battery side. I've never seen this before.
Does anyone have any views? Could this be the problem ... or is it a quirk of the fiat 500.

The wiring diagram doesn't show a condenser fitted to the coil.

The condenser inside, or mounted to the distributor is to suppress the tendency for the spark to jump as the contacts open. Inside, it is like a long roll of insulated foil, effectively giving a long dead end for the current. As the contacts open, the current will take the path of least resistance, and head off into the condenser. When it finds a dead end, it is then too late to jump the contacts, as teh gap is now too big. When these fail, you get sparking at the contacts, which burn them, and give a weak spark at the plug.

The extra one at the coil does a different job. It is there to suppress the electromagnetic field, which can cause interference with a radio, although more likely on the old AM wavebands. FM radios suffer less, and most will have suppression circuitry inside. I'm not sure what these are like inside, but when they fail, they will usually stop the ignition. Disconnect it. It is safe to leave its connector dangling, as long as it will not reconnect itself. If the ignition then works, bin it. If you have a radio, and you then get interference, usually crackling in unison with the engine firing, get a new one.

Had one fail on a 131 Mirafiori, (1988) on the way to work one morning, engine cut, as did the rev counter (nice clue). Coasted to a stop, lifted the bonnet, disconnected it, restarted, continued. Never did replace it, no issues with the radio.

Yes the second condenser was the problem. Thanks very much.

portland_bill said:

The extra one at the coil does a different job. It is there to suppress the electromagnetic field, which can cause interference with a radio,

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did this make you feel old? I remembered these too

dave said:

did this make you feel old? I remembered these too

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Oh, yes.
My head is full of this stuff. Mostly of no use any more. Glad to see the back of contact breakers though. Although the Mirafiori and Pandas could be adjusted using an allen key through a small hole, while the engine was running. Set the base gap, start the engine, adjust with a dwell meter. Still got a dwell meter, and a very expensive advance adjustable timing light. Lots of dust on them.

portland_bill said:

Oh, yes.
My head is full of this stuff. Mostly of no use any more. Glad to see the back of contact breakers though. Although the Mirafiori and Pandas could be adjusted using an allen key through a small hole, while the engine was running. Set the base gap, start the engine, adjust with a dwell meter. Still got a dwell meter, and a very expensive advance adjustable timing light. Lots of dust on them.

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i found Gunson Colortune and carb balancer in my last shed tidy. just googled them and you can still buy them mine are nearly 30 years old and look the same

dave said:

i found Gunson Colortune and carb balancer in my last shed tidy. just googled them and you can still buy them mine are nearly 30 years old and look the same

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I had a colourtune, never had much success with it. It might still be in the garage, or might be in my dad's crap. Brother would be better off with it, he's got all the old cars, although chance of any working ever again is slim.