Triumph Repair: Starting A 1500 Spitfire- No spark, ballast resistor, electronic tachometers

Question
Hi, I have a 1976 Triumph Spitfire. The other night whilst driving the tachometer fluttered with no apparent pattern or reason for doing so; i rationalized this to the cars age age this being the original tach though i quickly took the car home and parked it for the evening. The following morning i went to start the car and it sounded as though the battery had been drained. I then charged the battery and replaced the on terminal connection because it was loose and though that it may not have been charging due to this. Upon trying to start the car the motor spins but there is no spark going to the plugs. The car has an aftermarket electronic ignition mad by a brand called "piranha". I checked the coil and there is power going to it as well as the box for the electronic ignition. I have not gone inside the distributor. Upon looking at a wiring diagram it appears as though the car should have a "ballast resistor which is not on the car. I really hve no idea where to go or what else could be the problem. I spoke with my cousin who is a mechanic and had him look at the car as well, he also is not sure what could be the problem. Though he is not familiar with British cars either. I hope that you can help me. Thanks in advance, Kyle.

Answer
Kyle,

?  "the on terminal"?

I'm guessing you mean one of the battery terminals was bad?  Or a different connector?

On the '76 Spitfire the ballast resistor is a piece of wire in the wiring harness that has a fixed resistance.   Typically it's buried in the wiring harness.

The way the ignition system works is that power is fed to the + terminal on the coil and the - connection is opened and closed to charge up the coil (points closed) in order to get a spark (points open).

The Piranha unit replaces the stock points and condensor with an optical sensing unit and an electronic switch.

The electronic tachometers are connected to the - terminal on the coil and sense the switching rate ie: points closed, points open, or in the case of the Piranha whether the tranister is making the connection to ground.

Having the tach start jumping around suggests that either there is a loose connection, either at the coil, or possibly the ground on the battery.  


At:  

http://www.triumphspitfire.com/piranha.html

is a set of the installation instructions for the Piranha unit, including trouble shooting instructions.

That may help you sort out what's going on.


Cheers,

Jim