No spark from the distributor to the plug wires

[Mac2Night]

Some of you may have seen my earlier post a couple of weeks ago where I was not getting any spark from my MSD #6420 ignition box to the coil.

Well, I replaced the MSD ignition box with a new digital unit (#6425) and I now have spark from the box to the coil wire going into the distributor, but no spark from any of the plug wires. Thinking it could be an issue with the distributor since I was getting spark to the coil wire, I pulled the distributor and replaced the magnetic pick, rotor and cap up over the weekend with a new ones, but I have not reinstalled it to test it out. The pick up was all rusty and the dizzy had contaminants in it that looked like sawdust almost. I cleaned everything out (changing the pick up was way more of a pain than I thought and the instructions did not give me any idea that you had to take the whole distributor apart to install it....MSD instructions suck IMO). I can't think of anything it could be that is not sending a spark from the coil into the distributor and to the plug wires.... any thoughts on why this might be happening? I know I will know that once I get the distributor back in I will find out if my work was successful, but I would also like to hear if you guys might think it could be something else keeping the spark from reaching the plugs. My whole system is MSD including the top of the line wires which were just installed less than 2,000 miles ago and worked perfectly.

A related issue with all the work that I have done is that in my haste, I forgot to make exactly where the rotor button was pointing when I pulled the dizzy (I have a general idea but not as accurate as I know I should have been). My recollection of how to rectify this is to start all over and put the #1 at top dead center and place the rotor pointing at the #1 plug wire to get the firing order back in sync. Am I right on this?

Any help is greatly appreciated as I need to get this truck running and back on the road soon (been down for three weeks now and frustrating as all get out)!

Mac

 

[ENDLIFE]

I went through some trouble with the Mallory HyFire box, the box wouldn't function at all, so I sold it and bought an MSD only to have the same problem. After a bunch of fighting and cursing, I ended up wiring the keyed hot wire to constant hot with an anti-theft switch, turned the key, and VROOOOM she fired up. I was just going to wire in a dash switch, I know there would be times I would forget to turn off the switch, so thats why I went with the anti-theft switch.
I don't know if this will solve your problems, but I know it solved mine with those quirky ignition boxes.

 

[broncnaz]

Well if you have spark going from the coil wire to the dist cap but not out to the plugs your issue is with the cap and rotor. Its possible the small contact in the center of the cap that touches the rotor may have fell out that would interrupt the spark going out to the plugs. or the rotor is not the correct one for your cap.
Your good on retiming. Just make sure you get it to TDC on the compression stroke. ie remove #1 plug and when you feel air comping out the hole thats the compression stroke stop at TDC. Insert Dizzy and your good.

 

[DirtDonk]

I think I asked this in the other thread (which you probably should just have continued with this new info I would say) whether you were getting spark to the coil wire while the engine was cranking or just during a test procedure to make sure the box is good.

If you're getting spark while cranking, then like was said, it's not the box or the coil or the pickup in the distributor.
If, on the other hand, you were testing for spark using jumpers and touching this wire to that, that would most likely be the distributor's trigger (magnetic pickup and stuff).

Let us know what type of testing you're doing exactly, to help us figure out what's going on.

By the way, have you verified that the rotor is turning when you crank the engine?

Paul

 

[BIG_UGLY75]

Replaced my distributor at oreilly got the lifetime warranty... Had to replace it twice, no prob.. Of course i also got my box at oreilly and had to replace it four timed(factory picked a horrible spot to put it, water damage) they replaced it every time... Not to sound like an oreilly rep. But... Get the warranty.

 

[Mac2Night]

DirtDonk,

Thanks for the insight. I did not put this new information in the earlier thread because often times, people don't continue to read threads that have been up for a while and overlook new information/updates to the problem. Plus, the first thread was related to not getting any spark and this is related to getting spark from the box to the coil but no further. In short, I thought I might get some help by posting a new thread about my current problems better than just continuing an old thread.

Now, as it relates to my ignition issue. Even though I get spark from the coil to a ground when I jumped it (with the distributor installed), I still didn't get a spark when cranking the ignition. Hence, I thought that the next kink in the chain could be in internal operations within the distributor. Some other sources have suggested making sure the rotor is push and seated properly, but the MSD rotor screws done and is fully in place. Like you said, if I get spark when jumping it, more than likely it is the magnetic pick up, so I replaced it but have been waiting on the new cap and rotor to arrive before reinstalling the dizzy to give it a try. I just thought in my wait, I would continue to ask for advice as to what my issue might be to not overlook a piece of the puzzle.

Thanks for your help and for those others who are giving me feedback.... I just want this motor to fire up!

Mac

I think I asked this in the other thread (which you probably should just have continued with this new info I would say) whether you were getting spark to the coil wire while the engine was cranking or just during a test procedure to make sure the box is good.

If you're getting spark while cranking, then like was said, it's not the box or the coil or the pickup in the distributor.
If, on the other hand, you were testing for spark using jumpers and touching this wire to that, that would most likely be the distributor's trigger (magnetic pickup and stuff).

Let us know what type of testing you're doing exactly, to help us figure out what's going on.

By the way, have you verified that the rotor is turning when you crank the engine?

Paul

 

[DirtDonk]

There could be another culprit when cranking. Perhaps the ignition is not getting power during crank? It might get power when the key is in RUN/ON, but not when in START.
That's how the stock switch works in most cases anyway. The Brown "I" wire on the starter relay takes care of that with a stock ignition. I wonder it that could have any bearing here?

Usually, when this is the case, the engine will try to fire just at the last minute when you let off the key. But if the engine is not rotating fast enough, often it won't be able to start.

Even though it really doesn't "feel" like this is your problem, it might be worth a quick test anyway? Just test for voltage at the power feeds when the key is in START and see what you find.
Do you have new wires all around? Are you using a resistor wire to the coil or full 12v?
When you're testing the coil with the jumper, are you testing the coil directly, or through the box according to MSD's instructions?
If the coil directly, then there is no proof that your ignition box even works yet. It has to be done through the box itself to make sure that the box and coil are on speaking terms.
I hate to even say this, because I like the jump-to-ground spark test too. But I would not use it anymore. You now have too many delicate electronic devices (the MSD Digital-6) that might be overly sensitive to errant sparkage.
At the very least, if you weren't already, jump the spark as far away from the ignition controller as physically possible. You can fry a Pertronix Ignitor internal trigger in a flash when using this method. The MSD is more protected by it's case and it's mounting farther away from the potential spark, but it's still a delicate piece buried down in there. So be careful.
I now use a timing light on the individual wires to detect a spark when I can. And a longer "test" spark plug wire hooked to a spark test gauge when I don't have the use of a timing light.

And don't forget to check for rotor phasing too. It's hard to imagine a cap all by itself being bad enough to keep the mega-spark that these things put out away from all eight spark plug towers consistently.
A rotor maybe, but the cap? Hard to say. I've heard of it before, it's jut that after seeing what kind of spark these things are capable of, it's hard to imagine it not being able to jump to at least a couple of the plug wire towers.

Did you make sure your rotor is turning in the distributor with the engine cranking?
Ok, and I'll ask it anyway. Have you totally verified and reverified that you're on TDC of number 1 when the rotor is pointing at #1 and that your firing order is correct?
That won't make a no-spark condition at the wires of course, but it will effect how it works when you do finally get somewhere with the plug wires.

I hear what you're saying about too many people possibly overlooking an old tired thread. But my point was that if you have what is literally a continuation, even if a slight variation, of an existing subject, at the very least you'll have the attention of every one that had replied to the previous thread when they get an automatic notification that something had been added. And then we would be compelled to at least go have a look.
I know I get "compelled" that way. Just can't stay away from a good update!

Paul

 

[Mac2Night]

Paul,

Thanks for even more info! I can't believe the amount of info you are able to lend on this one topic, but again that is why I love being apart of this board in addition to the love of the best truck ever made.

Okay, so you actually might be on to something with the voltage at "crank" vs. voltage at "on" when you stated "Usually, when this is the case, the engine will try to fire just at the last minute when you let off the key. But if the engine is not rotating fast enough, often it won't be able to start."
We only tested it in the on position but never at crank. I had only owned the truck three days when this problem occurred. Before everything went south, I had noticed that the truck was slow to start in some strange way..... nothing I could put my finger on, but it seemed to have like a little of a delayed start. The wire used from the switch is a red wire that was hooked up to the previous MSD box so I used it again. I did notice a brown wire in the same cluster that we tested for voltage with the switch on and it received 12 volts as well as the red wire. I think I should look at testing both for voltage at crank to see if there are any differences.

No resistor wire to the coil, just the MSD wiring harness from the box to the coil. Yes, I am testing through the box as MSD recommends. I have not verified if I am now on TDC because it was when the truck was running as I drove it 3 hours from the seller's home without it missing a beat (drank a lot of gas though with that 460) so the firing order and all of that should have been perfect. Yes, I have checked to see the rotor turning when I crank the engine.... everything good there.

After many conversations with the previous owner/and builder of the truck (he never had any issues according to him), I recently learned that the wiring harness was replaced from another truck ('72) even though the motor ('75 460 from a Ford Club Car) and drive train ('79 F150) had been used to create the truck. Because of this, the build never used the factory ignition wiring other than the red power supply from the switch. Any stock ignition wiring to the coil, distributor and ignition box was done away with (hence I can't just hook up a Duraspark system to replace the MSD ignition installed).

I have a stronger feeling that it might be as you mentioned, the power supply wire from the switch. My next move will be to test the voltage at crank and see what happens there.

I will keep you posted (in this thread) as I work my way down the chain!

Thanks,
Mac

There could be another culprit when cranking. Perhaps the ignition is not getting power during crank? It might get power when the key is in RUN/ON, but not when in START.
That's how the stock switch works in most cases anyway. The Brown "I" wire on the starter relay takes care of that with a stock ignition. I wonder it that could have any bearing here?

Usually, when this is the case, the engine will try to fire just at the last minute when you let off the key. But if the engine is not rotating fast enough, often it won't be able to start.

Even though it really doesn't "feel" like this is your problem, it might be worth a quick test anyway? Just test for voltage at the power feeds when the key is in START and see what you find.
Do you have new wires all around? Are you using a resistor wire to the coil or full 12v?
When you're testing the coil with the jumper, are you testing the coil directly, or through the box according to MSD's instructions?
If the coil directly, then there is no proof that your ignition box even works yet. It has to be done through the box itself to make sure that the box and coil are on speaking terms.
I hate to even say this, because I like the jump-to-ground spark test too. But I would not use it anymore. You now have too many delicate electronic devices (the MSD Digital-6) that might be overly sensitive to errant sparkage.
At the very least, if you weren't already, jump the spark as far away from the ignition controller as physically possible. You can fry a Pertronix Ignitor internal trigger in a flash when using this method. The MSD is more protected by it's case and it's mounting farther away from the potential spark, but it's still a delicate piece buried down in there. So be careful.
I now use a timing light on the individual wires to detect a spark when I can. And a longer "test" spark plug wire hooked to a spark test gauge when I don't have the use of a timing light.

And don't forget to check for rotor phasing too. It's hard to imagine a cap all by itself being bad enough to keep the mega-spark that these things put out away from all eight spark plug towers consistently.
A rotor maybe, but the cap? Hard to say. I've heard of it before, it's jut that after seeing what kind of spark these things are capable of, it's hard to imagine it not being able to jump to at least a couple of the plug wire towers.

Did you make sure your rotor is turning in the distributor with the engine cranking?
Ok, and I'll ask it anyway. Have you totally verified and reverified that you're on TDC of number 1 when the rotor is pointing at #1 and that your firing order is correct?
That won't make a no-spark condition at the wires of course, but it will effect how it works when you do finally get somewhere with the plug wires.

I hear what you're saying about too many people possibly overlooking an old tired thread. But my point was that if you have what is literally a continuation, even if a slight variation, of an existing subject, at the very least you'll have the attention of every one that had replied to the previous thread when they get an automatic notification that something had been added. And then we would be compelled to at least go have a look.
I know I get "compelled" that way. Just can't stay away from a good update!

Paul

 

[DirtDonk]

Now I need to fuss at you for real! When were you going to tell us that this was a 460 in a re-wired Bronco with things just hooked up willy-nilly?
Ok, I'm just bustin' yer chops, as that particular info might not really change anything anyway. Just letting you know that every little tidbit of info can be of help. Any one thing can lead us to the right answer.
The only real info we have on what you might be working on at the moment is in your signature. And I take it this is not your half-cab with a 6-cylinder?

Now, I think it's time for some pics. Let's see how this baby is wired and laid out. Need to see the starter relay corner of the fender, the MSD area including it's wires and where they go, then the coil and what's hooked to it.
Oh, and if you're still young and limber, a shot of the back of the ignition switch might be in order as well. That's a tough one, but can be worth it.

Maybe it's something obvious, maybe not. Probably not, but it's still worth a look-see.

Thanks

Paul

 

[Mac2Night]

Okay Paul, so you caught me on which of my 3 trucks this problem was occurring ;D

Here are some photos as requested (except from the back of the switch which I pulled last week and is all original and in good shape).

Photo #1 is of my new MSD 6AL digital ignition box and its wiring harness:
- thick red and black go to battery or positive and negative of the solenoid;
- harness with orange and black wires go to the coil;
- harness with green and purple wires go to the distributor pick up;
- thin red wire supplies the 12 volts and goes to the ignition switch;
- white wire is not used (only for points distributor).

Photos #2,3,4 show coil hooked up, pick up connections (unhooked because the dizzy is out of truck) and the red switch wire to switch harness

Photo #5 is of the new starter solenoid with connection (replaced all cables with new ones and added an extra ground as per the MSD tech I spoke with on the phone)

Now I need to fuss at you for real! When were you going to tell us that this was a 460 in a re-wired Bronco with things just hooked up willy-nilly?
Ok, I'm just bustin' yer chops, as that particular info might not really change anything anyway. Just letting you know that every little tidbit of info can be of help. Any one thing can lead us to the right answer.
The only real info we have on what you might be working on at the moment is in your signature. And I take it this is not your half-cab with a 6-cylinder?

Now, I think it's time for some pics. Let's see how this baby is wired and laid out. Need to see the starter relay corner of the fender, the MSD area including it's wires and where they go, then the coil and what's hooked to it.
Oh, and if you're still young and limber, a shot of the back of the ignition switch might be in order as well. That's a tough one, but can be worth it.

Maybe it's something obvious, maybe not. Probably not, but it's still worth a look-see.

Thanks

Paul

 

[Mac2Night]

Photo must be too large and I can't edit the on the cussed Ipad!

 

[Mac2Night]

#3 of five photos

 

[Mac2Night]

#4 of five

 

[Mac2Night]

And finally

 

[broncnaz]

Did you double check the rotor button in the dist cap? make sure its there and make sure the tab on the rotor is contacting the button. It helps to bend that shiny tab up a little to make sure you have good contact. also inspec the cap for carbon tracking as that could cause the spark to go elsewhere.

Not that your going to swap back but.
In all actuality its not that hard to wire in a factory duraspark setup. About all you would need is a resistor for the coil. Just go by the wiring diagrams found on the web. its no more complicated than your MSD setup.

 

[DirtDonk]

Thanks for the pics Mac. And I think I found at least one issue.
That wire on the right hand stud of the starter relay is NOT a ground, first of all. So if your Black wire is attached there, it's not getting it's dose of happy juice.
When the starter is not spinning, the Black wire is probably grounding through the starter case somewhat. Allowing you to get a spark using the MSD tests.
When the key is in START however, the box is getting positive voltage through both wires. Not exactly by the book.
I would hope that this has not messed with the circuits inside. It might be protected from just such a happening, but not sure.

Take the Black wire and move it to one of the mounting screws for the relay/solenoid instead. See what happens then.

Paul

 

[Mac2Night]

Paul,

That makes sense. Originally, the black wire was connected behind the solenoid mounting screw but it was loosely attached (hole the screw mounted to was wallowed out a tiny bit) so I moved to the post). I didn't even think that it is the post that sends positive juice to the starter! I will immediately make the switch.

Thanks for noticing that!

Thanks for the pics Mac. And I think I found at least one issue.
That wire on the right hand stud of the starter relay is NOT a ground, first of all. So if your Black wire is attached there, it's not getting it's dose of happy juice.
When the starter is not spinning, the Black wire is probably grounding through the starter case somewhat. Allowing you to get a spark using the MSD tests.
When the key is in START however, the box is getting positive voltage through both wires. Not exactly by the book.
I would hope that this has not messed with the circuits inside. It might be protected from just such a happening, but not sure.

Take the Black wire and move it to one of the mounting screws for the relay/solenoid instead. See what happens then.

Paul

 

[DirtDonk]

Yep, wallered out holes sounds very familiar!

If smooshing down the lips of the holes, or using larger screws does not help, just use machine screws with nuts for a good solid mount.

Since the relay grounds through it's mounts for proper function anyway, this is the perfect time to sand down the spots clean for a good contact with the body, doing whatever it takes to make the mount solid and tight, and verifying that the main Negative battery cable has an additional grounding wire to the body.
The big cable to the engine block is important of course, but mainly for starting and charging. The wire from the battery to the body is absolutely critical to the functioning of the rest of the truck's electricals.

Paul

 

[Mac2Night]

GOT IT RUNNING! So after (4) weeks of on-and-off work on my ignition gremlins, this past weekend I got the truck started.

I ended up replacing:
1) MSD ignition box
2) MSD magnetic pickup
3) MSD cap and rotor
4) MSD coil
5) Starter solenoid
6) Battery and starter cables

I repaired, checked or added:
1) Two new ground wires (one to body and one to body)
2) 12 volt wire from switch to MSD box
3) Spark plugs (just because I was into the ignition, thought it wouldn't hurt)

I first started one item at a time with no results and then I just got frustrated and added the remaining items so the whole system was new... obviously it worked and at this point, I don't even want to know which item was causing my trouble.

Set the timing and it is roaring like a kitten (built 460 BB).

Thanks to Dirtdonk (Paul) for all of your trouble shooting suggestions!

Mac

 

[DirtDonk]

Hey, I like the sound of roaring kittens!
Enjoy every BTU that the fuel puts out as that sucker sucks it up.

Paul