Misfire/stall Fiat 124 Spider

[ystephen]

Shortly after gassing up and cruising at about 70 mph, my Fiat 124 Spider misfired, backfired and stalled out. When that has happened in the past it has been because of an over-heated ignition coil. I carry an extra and when I have replaced it, the car starts immediately and runs well. This time, not. Had to get a tow home. The car will start and run for a few moments, misfire, with the tach jumping, and stall and refuse to start for some time. The battery charge indicator does not come on when the key is on, however, the battery seems to be holding a good charge. I've used dry-gas just to make sure the recent fill-up wasn't at fault and have put in a new coil. Any suggested diagnoses would be appreciated.

[124JOE]

are you using points?

[AriK]

The red warning lights are on the same circuit as the pink wire that goes from the ignition switch to the coil, and circuit is hot when switch is set to on and start. If your ignition switch is faulty it may not be sending power to that circuit. Sometimes a gentle feel in back of the switch may animate the terminals to temporarily work. Also check the connector which is 6" behind the switch and ensure that the connectors are clean and tight.

[Boris61]

I had a similar experience (2L FI) and it was caused by worn contacts on distributor cap. Replaced cap and problem was fixed. Of course I also did a complete tune-up when I got home since the other ignition parts were also old.

[ystephen]

Thanks for all the suggestions thus far. I've done quite a lot of car mechanics, but not so much on the electrical...what is the procedure for testing voltage at the coil?

[AriK]

The ignition coil has 2 small terminals as well as the primary terminal which is the one that connects the ignition cable to the distributor. Turn on the ignition switch and connect a test light to the pink wire vs the ground on the car, this will prove you're getting 12V from the switch.
Connect a spark plug tester or hook a timing light to the primary lead of the coil and crank over the motor to test if your coil is giving fire to the distributor. You can test the wires that go to each plug in the same manner.

[So Cal Mark]

a test light doesn't guarantee the presence of 12v, merely enough power to illuminate the light. Use a voltmeter

[ystephen]

So, as stated earlier, my '77 Fiat 124 Spider stalled on the freeway at about 70 mph and would only start and
run briefly, if it would start at all. After much testing, I thought I had it figured out; I have 12 volts at the coil,
but the Fireball XR700 optical trigger failed to light, indicating the pick-up or module was bad. I confirmed this test and diagnosis
with a tech at "Fast," the company that bought out Fireball from Crane Cam. I have installed the new module and
pick-up (optical trigger) and tested it to make sure it works. Now, the car starts right up, but the battery charge
indicator light in the instrument cluster still isn't lit when the key is in the "on" position and comes on after the car
has run for just a moment and the car then immediately stalls out. Any suggestions or insight?

[baltobernie]

The red warning lights are on the same circuit as the pink wire that goes from the ignition switch to the coil, and circuit is hot when switch is set to on and start. If your ignition switch is faulty it may not be sending power to that circuit. Sometimes a gentle feel in back of the switch may animate the terminals to temporarily work. Also check the connector which is 6" behind the switch and ensure that the connectors are clean and tight.

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