How do you diagnose your ignition system?

[6Stang7]

My engine still runs no where near par. I can still pull wires off cylinders and not hear a change in the idle. I am wondering if anyone knows of a write up or can tell me what tools I would need and how to completely disgnose my ignition system so I can either find out what it wrong with it, or totally eliminate it as a problem.

 

[pabear89]

Read the Ford Manual.



A timeless Wisdom.


It will have a trouble shooting section.


PB

 

[2nd Mustang]

If you can pull plug wires and not hear or feel a difference, I would say it really sounds like an ignition problem. I would invest $40 some odd dollars in a manual before changing parts randomly.

(Darn, that Pa Bear beat me to the response, oh well, he's right though.)

 

[6Stang7]

My ignition system isn't stock anymore. I am wondering if too much voltage to a coil could cause my plugs to randomly not fire?

 

[2nd Mustang]

Although the theory of the ignition system should stay the same, once modified, you've thrown in some new wrinkles into the equation. As I've always thought, electrical gremlins are the worse because you usually cannot find the real cause until whatever caused the problem goes completely dead instead of intermittent problems.

 

[slapper]

My engine still runs no where near par. I can still pull wires off cylinders and not hear a change in the idle. I am wondering if anyone knows of a write up or can tell me what tools I would need and how to completely disgnose my ignition system so I can either find out what it wrong with it, or totally eliminate it as a problem.

Tall order.
Put a timing light on each plug wire one at a time to see if secondary spark is being produced at the cap. Slowly rev the engine up to about 2500 RPM on each test to ensure that the spark is consistant and not erratic.
Visually check each spark plug for any kind of damage. Use a 10X magnifying glass to check for cracks in the white porcelin insulation. If I ever drop a spark plug, I consider it toast, and try not to use it. Plug color?
Clean out the distributer cap with brake clean or other elctro cleaner that does not leave behind any film or residue. Dry thoroughly. Look for tiny cracks in the cap, and ensure it's seated snuggley on the distributor without any gaps. Examine the rotor for cracks also. Clean the inside ends of plug wires, Q-tips, no corrosion or dirt allowed.
Points or solid state primary circut?
Take a close look at the distributor cam. Loose? Dirty?
Distributor shaft-Loose? Excessive play?
Coil- Gets really hot? terminal posts loose?
Primary wires going to coil- Good condition? Good ground in the distributor cap?

 

[6Stang7]

Tall order.
Put a timing light on each plug wire one at a time to see if secondary spark is being produced at the cap. Slowly rev the engine up to about 2500 RPM on each test to ensure that the spark is consistant and not erratic.
Visually check each spark plug for any kind of damage. Use a 10X magnifying glass to check for cracks in the white porcelin insulation. If I ever drop a spark plug, I consider it toast, and try not to use it. Plug color?
Clean out the distributer cap with brake clean or other elctro cleaner that does not leave behind any film or residue. Dry thoroughly. Look for tiny cracks in the cap, and ensure it's seated snuggley on the distributor without any gaps. Examine the rotor for cracks also. Clean the inside ends of plug wires, Q-tips, no corrosion or dirt allowed.
Points or solid state primary circut?
Take a close look at the distributor cam. Loose? Dirty?
Distributor shaft-Loose? Excessive play?
Coil- Gets really hot? terminal posts loose?
Primary wires going to coil- Good condition? Good ground in the distributor cap?

I'll have to do the timing light test. What do you mean by secondary spark? Right now I have a Pertronixs solid state and 40K volt coil from them.

 

[6Stang7]

Little up-date. I pulled the plug wire off each cylinder (one at a time) and could hear and feel a very very very very slight change in how the engine ran; however, it was really hard to notice. So the problem I am having isn't just with any one particular cylinder, but with all. Any ideas on what int he electrical system I should check? Could this be the sign of carb trouble?

-Shaun

 

[slapper]

Little up-date. I pulled the plug wire off each cylinder (one at a time) and could hear and feel a very very very very slight change in how the engine ran; however, it was really hard to notice. So the problem I am having isn't just with any one particular cylinder, but with all. Any ideas on what int he electrical system I should check? Could this be the sign of carb trouble?

-Shaun

Sorry, for the short answer, I've only got about 1 minute.
Check the primary circuit--coil, wires to and from it, make sure the petronix is gapped about .045 or so. try another coil for testing purposes.

 

[Zooted_plus]

I have the same ignition setup as you do, the pertronix ignitor and coil using stock distrib. When I hooked mine up, I used the resistor wire, and recently read this article saying that the coil needs a full 12 volts. Anything less and the system will not operate efficiently.

http://www.geocities.com/a65ragtop/VM_FAQ/mechanical/pertronix_wiring.html

I put a multimeter on my coil + while the engine was running and I'm getting about 10.8 volts at the coil.

 

[6Stang7]

I have the same ignition setup as you do, the pertronix ignitor and coil using stock distrib. When I hooked mine up, I used the resistor wire, and recently read this article saying that the coil needs a full 12 volts. Anything less and the system will not operate efficiently.

http://www.geocities.com/a65ragtop/VM_FAQ/mechanical/pertronix_wiring.html

I put a multimeter on my coil + while the engine was running and I'm getting about 10.8 volts at the coil.

Are you using a digital meter? If you are, then you can't trust that reading. The solid state is causing the circuit to open and close rapidly; therefore the meter is getting a high reading (when you are getting voltage) and then a low reading (when the circuit is open showing 0 volts) and it is averaging the two together. You need to use an oscilloscope to get an accurate reading.

 

[68GEETEE]

I assume you have ruled out an intake leak or vacuum leak. I am not a mechanic by any means, but I am wondering if somehow you have a bad ground causing an electrical gremlin of sorts. If this is wrong, ignore me