Jump to content

Intermittent Spark from Coil - Need Assistance Please


Recommended Posts

I'm at my wit's end on this one.  Here are the details.


- Engine out refresh, 5 speed while at it

- IE Electronic Distributor

- New Plugs

- New Plug Wires

- New Coil


Car was running fine.  I don't have a lot of miles on it since I put it all back together but it was running well and I was sorting things.  My son and I took a 50+ mile drive.  We arrived home and while it was warm, I wanted to use the timing light to set the timing.  I had tuned it by ear and car was running rather well.  Maybe I should have left well enought alone.  During this time it just died.  It turns out that it lost spark.  There was none at the #1 plug.  I pulled the Wire from the coil to the distributor at the distributor end - no spark.


I checked connections at the coil, checked fuses and mucked around without doing anything appreciable.  I eventually had spark.  I put the plug in and it fired right up, ran great and then died.  I figured I had a bad coil even though it was new and replaced it.  No spark from the coil wire with the new coil.  I checked fuses, and tried again and had spark.  So, I put the coil wire back on and tried to start it to no avail.  I pulled the coil wire and no spark again.  Eventually, it will generate a spark and the car will run just fine but I cannot determine what is causing the intermittent spark.  By the way, the coil has never felt warm, even the original new coil.


This has occurred over several days.  It would seem that if I hold my tongue in a certain manner and say nice things, it might create spark.  Or, it may not.  There seems to be zero rhyme or reason to this one which means I'm missing something.  


What am I missing here?  I was thinking that the coil was failing but now I suspect a wire. Before replacing the coil, I checked resistance on the new wires from the IE Electronic Distributor.  They were fine.  One of the older existing wires had given me a problem in the past.  I had placed a new end on it and that solved it.  Knowing this, I peeled back some insulation on each of the two old wires near the firewall.  I checked for resistance and both checked out fine but I replaced the other end just to be sure.  Maybe one is broken further back?   


If I put a meter on the coil measuring DCV (positive and negative post) with the key in the on position but not starting the car, I get nothing; as in a zero reading. I am turning the key until the dash light comes on.  Unfortunately, my arms aren't long enough to try and start it while measuring this at the same time but I would think that it should be supplying 12 volts at that point.


I did try using the search function and apologize in advance if I'm bringing up some common problem.


Any thoughts?   


Thank you in advance.

  • Like 1
Link to comment
Share on other sites

Thank you to everyone that has responded so far.  I have a '75 so I don't believe that I have the relay box mentioned by ray_




I didn't remove anything when I converted to the electronic distributor.  I didn't use the existing black wire if that's what you're referencing.  I ran two new wires from the new IE distributor to the coil.  Is that what you meant?


@1974_Verona I was wondering if the distributor might be the issue after I typed all of this.  I didn't initially suspect it as it's new but I also didn't realize they were problematic as I thought that IE was reputable.  

Link to comment
Share on other sites

12 minutes ago, EPK said:


@1974_Verona I was wondering if the distributor might be the issue after I typed all of this.  I didn't initially suspect it as it's new but I also didn't realize they were problematic as I thought that IE was reputable.  

I suspect IEs intentions are honorable. Ive read many threads about their dizzy having a sub par quality pick up (I have no personal experience with it). I went with the 123Igntion Tune unit. THAT is built like a Swiss watch. 

Link to comment
Share on other sites

What he means is, it's the distributor.*


Because it's not the coil unless you open the hood and find the coil on fire.




(No disrespect to preyupy, I'm mostly joking)


Actually, did you say the ballast resistor is still in line? They can get hot and open the circuit.




*If your 12v source is constant.

Link to comment
Share on other sites



I'm not sure that I did it correctly.  I disconnected both the positive and negative leads from the distributor to the coil.  I disconnected the coil to distributor lead at the distributor.  With the key in the on position, I grounded the negative side of the coil to the chassis.  Once disconnected, I get a spark at the chassis but not out of the coil wire.  


Does that make sense?  


This coil is the second new one and I still have the original as well.  It was working when I replaced it but with fresh engine internals, I figured I should replace all the older systems.  I would be surprised if I have 2 new coils that are bad but you never know.



Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Upcoming Events

  • Create New...