Hi all.

I have a 62 falcon, 170 IL 6. I have a strange issue. For the engine to start I need spark, compression, and fuel.

I can get the car to start intermittently... When it runs it sounds good but the even with the gas petal down, and the time it's running depends, it will just cut off.

As far as the spark, it's not a bright blue or seems strong enough at all... Very dim spark and even non existent during cranking at times. The battery seems to be draining quite fast upon cranking as well.

I haven't gone crazy with purchasing parts yet because I really want to try troubleshooting it. I've changed the plugs, cap and rotor, and got a new coils. Points seem fine. #1 cylinder at TDC is fairly close to #1 on distributor.

If I can remember I got like 6.8vdc at the coil when the ignition was on. Not even sure what the voltage should be???

Is there anything else that can cause week or no spark besides the coils. I'm beating my head over what else could be the issue... And I'd rather not go out and just start buying parts. Maybe a specific wire could be brittle or something but not sure what one.

Thanks everyone, any input would be greatly appreciated....

 

If the car's electric system is on 12V, then this is what you should be seeing at the ignition coil's primary winding. If it's on 6V (some old cars were like that, especially in Europe), then you should see 6V.

The ignition coil is an electrical transformer with two windings. The primary has fewer turns and is "pulsed" between 0 and 12V from the battery via a mechanical switch (cam switch) that interrupts the circuit once for each cylinder, when the distributor connects the coil output to the right spark plug. While the current flows through the primary winding, the electricity gets stored as magnetic energy into the core of the coil. When the circuit is suddenly interrupted, that energy is used to keep the current flowing (this is also causing the spark that you can see when powering a relay from a battery ... the spark will only show when you cut the circuit, but not when you make it). However, the ignition coil has a secondary winding - with a lot more turns - which generates a high voltage impulse when the current flowing through the primary coil is interrupted. This high energy / high voltage spike produces the spark on the spark plug. That's a primer on the theory behind ignition.

Back to your problems: I suspect that the circuit powering the induction coil via the cam switch is in poor shape (high resistivity due to poor cam contact shape or some other problem elsewhere). Back in the days when I was driving a car with this kind of ignition system, I used some fine sandpaper to clean up the cam contacts, although this is likely to cause irreversible damage to the platinum coating on them. Proceed with caution. Try to apply a 12V pulse directly to the primary winding of the ignition coil and see if the spark is still weak. If it is, then the problem is with the coil. If the spark is fine, then check the rest of the ignition system.

Let us know, and good luck!

Cheers,
cougar_fan

 

Thank you very much for all that info... Great explanation.

So far I have not sanded the points.... Dark out right now. The spark from the coil wire to a good ground is strong... Easily jumps more then 1/8.

With the points open I'm getting 6vdc and with them closed I get 12. When cranking I only get 8.5 which I believe I should be getting 12. I do need battery, it's pretty week so I' m getting one this week.

Could this just be a points issue perhaps....???

Thanks again

 

WOW...Points...Haven't played with anything using points since I last set the timing on my 1977 SkiDoo Olympic 440. Being you changed everything else, I would also have replaced the points and condensor. Not only does the point surface wear, the nylon slider also wears affecting gap setting which in turn affects how long the points are open for affecting your spark strength/duration.

 

IMO, with the points open you should see zero volts at the coil terminals ... if you see some voltage there, it could be a sign for a short somewhere else.

It's normal that the voltage drops during cranking, the starter motor is a huge (albeit brief) load for the battery. Try a new battery, although I don't think the battery is your problem here ... just make sure you can return in (unless you needed it anyway )

Good luck!

Cheers,
cougar_fan

 

If I'm not mistaken, with the key on and the points open you should see battery voltage at the coli + terminal. When the contact points close the primary coil circuit is now complete. When the points open the magnetic field collapses and the collapsing magnetic field induces a high secondary voltage that goes out the coil tower to the dist cap etc. This goes back some, but there were coils that operated on 12 volts and coils that operated at a lower voltage. The lower voltage coils used a dropping resistor either in the wire from the ignition switch or a resistor block. Most of those coils had a notation on them that stated which voltage it was for. I don't remember which one a 62 Falcon used . From what I have gathered so far ,the weak battery is some of the problem, but poor contact at the contact points could also influence your coil output.
Also make sure the point gap is in the area of .025 in. with the contact point rubbing block on the high point of the dist cam. Where did you find that car? Used to own a 64 Falcon. It was a jewel, never got stuck, handled like a dream, and they all had blow-by problems eventually. My wife loved that car !

 

I do have a really good spark at the coil wire to ground... I found another forum with basically the same issues and it was the condenser believe it of not, could be. Worth a shot it's a cheap part.

I will go with an electronic ignition at some point but just not now... thanks everyone.

Goin to try the new battery and condenser this week and see what happens.

 

Yes , that's a good possibility. Only had one instance where that was the problem. Not very common.

 

ITS RUNNING AND SOUNDS GREAT!!!!!!

It was the condenser.... $5 part. Thanks everyone, I learned a lot on this one with minimal money spent.

 

I just read this, and aged another 25 years in 3 seconds. I'm too young to say this much, but I GREW UP WORKING ON THESE!