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Can Not Figure Out Why No Spark at Plugs

73LemonTwist

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This spring it has been nearly impossible to get the car to fire up. I have never had ignition problems before so this is a new experience. I have an MSD 6A ignition module and am using an MSD blaster coil.

When I put my timing light on any of my plug wires and crank the engine see no spark. When I put the timing light on the wire between the coil and the distributor cap I see lots of consistent, steady spark when I crank the engine.

I have tried various cap and rotor combinations, and I have replaced the coil. I still get no spark at the cylinders. If I get lucky and it kicks, it will start and run and once its running I have no issues restarting the car, and the timing shows a consistent and regular plug fire. Leave the car over night and I am back in the will not start mode..

Any ideas, I am at a loss...

Allan
 
If the coil wire has power and the spark plugs are not getting spark, why would you replace the coil?
The coil is not the problem.
Electrical stuff is frustrating, partly because you cannot see what is wrong when it fails.
You can see when the gasoline isn't flowing freely.
You can see and feel a bad wheel bearing when it is ready to fail.
When you're not charging, you usually can't see the electricity directly, you have to trust a gauge.
You cannot see spark energy. You can see sparks when you see the bare end of a wire disconnected IF the other end of the wire is connected to something that IS working.
I recently had my own no spark issue and I wrote about it here.

Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

My situation was random. It could be months between episodes.
In short, I cleaned all the terminals and added dielectric grease to the bulkhead plugs, then replaced the ECM box and distributor. It hasn't failed since but I don't know if my situation is solved either. The advantage of a stock based system is the parts availability if I'm in need of replacement parts.
I never saw the advantage of an MSD setup.
 
If the coil wire has power and the spark plugs are not getting spark, why would you replace the coil?
The coil is not the problem.
Electrical stuff is frustrating, partly because you cannot see what is wrong when it fails.
You can see when the gasoline isn't flowing freely.
You can see and feel a bad wheel bearing when it is ready to fail.
When you're not charging, you usually can't see the electricity directly, you have to trust a gauge.
You cannot see spark energy. You can see sparks when you see the bare end of a wire disconnected IF the other end of the wire is connected to something that IS working.
I recently had my own no spark issue and I wrote about it here.

Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

My situation was random. It could be months between episodes.
In short, I cleaned all the terminals and added dielectric grease to the bulkhead plugs, then replaced the ECM box and distributor. It hasn't failed since but I don't know if my situation is solved either. The advantage of a stock based system is the parts availability if I'm in need of replacement parts.
I never saw the advantage of an MSD setup.
The solution is elegantly simple: take the car to someone that understands the situation OR sell the car and don t worry about it.
BOB RENTON
 
Or be worthless and post zero help like SOME people.
This forum is better when the members work together to help solve problems.
 
Allen do you have an extra distributor laying around? Did the car run before? Did you add the MSD setup?
 
Triple check power to the trigger wire for full voltage when cranking and the main power and ground to the box. Any butt connector is suspect.
Doesn't sound related, but just check
 
Sorry I have nothing to add. My first thought was the rotor, but OP said all that was changed. I had that happen also and found the graphite tip had come off the rotor. ruffcut
 
msd is very sensitive to full battery voltage and a solid ground, both should come straight from the battery
 
This spring it has been nearly impossible to get the car to fire up. I have never had ignition problems before so this is a new experience. I have an MSD 6A ignition module and am using an MSD blaster coil.

When I put my timing light on any of my plug wires and crank the engine see no spark. When I put the timing light on the wire between the coil and the distributor cap I see lots of consistent, steady spark when I crank the engine.

I have tried various cap and rotor combinations, and I have replaced the coil. I still get no spark at the cylinders. If I get lucky and it kicks, it will start and run and once its running I have no issues restarting the car, and the timing shows a consistent and regular plug fire. Leave the car over night and I am back in the will not start mode..

Any ideas, I am at a loss...

Allan
Have you altered the wiring since it last ran without any issues?

Have you checked for rodent damage - rats, mice, beavers, nosey elk etc .....

If the wiring has been altered or moved it is worth running through the diagram and checking everything is correct. Sounds to me like a bad crimped joint which is affected by heat - expansion or even a loose connection.
 
See ? THAT is what these forums are for. SHARING ideas and trying to help others.
Loose connections and improper grounds are really common and often the problem. Electrical stuff frustrates a lot of us. It is the unknown that sends us off in multiple directions looking for a solution.
I can deal with a known problem that I can identify.
It takes a real skilled person to diagnose a hidden or random problem.
I don't know if "misery loves company" brings the OP any relief but many of us struggle with electrical problems. I try to listen to those that are skilled with that stuff.
 
Or be worthless and post zero help like SOME people.
This forum is better when the members work together to help solve problems.
It seems that you are always fussing with the car.....trying to fix problems that may occured or have occured in the past.....why not just drive the car and enjoy it.....at local car shows or at the drag strip. Any problems, should they exist or develop can be dealt with at the time if/when they occur. Problems exist but sometimes they are imagned or manifest from an article in a magazine.......don't keep looking for them.....
BOB RENTON
 
Bob you are correct - I do love to tinker with the car - that is the point of having it - along with driving it, which it gets lots of.

Electrically, the car is the same now as it was last summer - nothing new other than I installed a BlueStreak cap and rotor before putting it away for winter - They have been removed and alternate caps/rotors installed to attempt to isolate the problem. Same reason for replacing the coil - had a new one in the garage, so gave it a try, and as expected, it didn't help/solve the issue. I am pretty confident that I can rule out cap/rotor/coil wire/coil.

The MSD is 8 years old and has worked flawlessly during that time. I do think the suggestion of chasing the grounds and power supply wires to make sure that they are solid is a really good idea. The MSD video Builderguy referenced is pretty good and gave a few ideas there to check. So will give that a try.

This afternoon I did swap distributors and put in an old Mopar unit and did succeed in getting the car running, - will see what a cold start tomorrow does.

Thanks for the thoughts folks - intermittents are always such a pain to find and resolve... This group always comes up with ideas that I haven't thought to try - hence the value of the forum...

Allan
 
SOME people don’t even have cars yet chime in.
Others may want to get ahead of potential problems so they can be prepared if or when they happen.
I don’t think it makes sense to jump into a pool THEN look to see if it has water in it while I’m mid air.
 
This spring it has been nearly impossible to get the car to fire up. I have never had ignition problems before so this is a new experience. I have an MSD 6A ignition module and am using an MSD blaster coil.

When I put my timing light on any of my plug wires and crank the engine see no spark. When I put the timing light on the wire between the coil and the distributor cap I see lots of consistent, steady spark when I crank the engine.

I have tried various cap and rotor combinations, and I have replaced the coil. I still get no spark at the cylinders. If I get lucky and it kicks, it will start and run and once its running I have no issues restarting the car, and the timing shows a consistent and regular plug fire. Leave the car over night and I am back in the will not start mode..

Any ideas, I am at a loss...

Allan
The only time I've had that problem - running fine normally but not after sitting all night - I found condensation inside the cap, allowing the spark to travel everywhere except the intended wires.
 
If your coil wire is getting spark and it's plugged into the cap it's finding a way to ground. Take a hair drier to cap and distributor to remove moisture. Check center terminal inside cap.
 
Bob you are correct - I do love to tinker with the car - that is the point of having it - along with driving it, which it gets lots of.

Electrically, the car is the same now as it was last summer - nothing new other than I installed a BlueStreak cap and rotor before putting it away for winter - They have been removed and alternate caps/rotors installed to attempt to isolate the problem. Same reason for replacing the coil - had a new one in the garage, so gave it a try, and as expected, it didn't help/solve the issue. I am pretty confident that I can rule out cap/rotor/coil wire/coil.

The MSD is 8 years old and has worked flawlessly during that time. I do think the suggestion of chasing the grounds and power supply wires to make sure that they are solid is a really good idea. The MSD video Builderguy referenced is pretty good and gave a few ideas there to check. So will give that a try.

This afternoon I did swap distributors and put in an old Mopar unit and did succeed in getting the car running, - will see what a cold start tomorrow does.

Thanks for the thoughts folks - intermittents are always such a pain to find and resolve... This group always comes up with ideas that I haven't thought to try - hence the value of the forum...

Allan
The point of having an old car is to fix it ONCE ...then drive it and enjoy it, going to cruises or take it to the Woodward Avenue Dream Cruise.....50,000+ cruise cars, last weekend in August (google it) The OP is dealing with minutiae, like one or two distributor advance degrees is something to worry about. Or setting the reluctor pickup gap or how to set the timing ir use vacuum advance or not or how to wax the hood or how to air the tires or how to use a timing light. These things are fundamental principles....like condensation under the distributor cap...dry it out and move on......if a person does not understand these aspects, perhaps they should become viewers and not participants or owners ...... just a thought......
BOB RENTON
 
^^^^ I am so glad I didn't start my coffee yet. :rofl: :rofl: :rofl: ...it would be coming out my nose now.
 
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