Ignition issue - continual weak spark

This is the last issue before I can finally try a wet start after the rebuild.

I have fitted a Power spark electronic ignition distributor, viper coil and leads. They were bought new 2 years ago and sat on the shelf since.

When I apply ignition, I can hear the distributor creating faint sparks (crackling)

With the black lead to the coil disconnected, there is no noise (shorting/crackling)

there are only 3 connections at the coil.

  1. IGN lead to + (white to tachometer)

2 Red distributor lead to +

3 black distributor lead to -

I have just gone out to the garage in the dark to try and see where this sparking is.

With ignition on, I could hear the sparking but couldn’t see anything (in the pitch black)

With ignition still on, I disconnected the distributor black (-) and the sparking stopped. I then reconnected and the sparking had stopped (with ignition still on)

I put a spark detector on cylinder 1 HT lead and turned it over. I got a bright spark during the firing stage but it also started to crackle again, and the detector showed a faint spark while it was turning over; plus the bright spark on the firing stroke.

I tried the same on cylinder 2 with the same result. Bright spark on firing stroke and continuous faint spark while turning over.

So is it the distributor and electronic ignition?

If you are hearing sparking or crackling upon ignition being energized and before crank you already know something is not right.

Check the primary wiring thoroughly before going any further.

Also, why introduce more variables before an initial start?

Wish you the best, but my money is on the new parts.(variables)

If you mean the electronic distributor and new coil…they are supposed to be more reliable improvements. All part of a total rebuild.
I don’t really understand your implication.

Further investigation…
I tried the following:

  1. distributor cap off and switched to ignition. Sparking/crackling still there (but not visible)
  2. cap back on. HT lead from coil removed. switched ignition on. Sparking/crackling still there (but not visible) much more audible though.
  3. cap on. HT lead to coil refitted. rotor arm removed. Sparking/crackling still there (but not visible)

Philip I do not know anything about Power Spark brand but perhaps this link matches for what you have in case it helps ?? I have a Pertronix module inside my original Lucas distributor. Luckily it has been trouble free in my E but the trouble shooting page that came with it says low voltage can be a common problem at installation. One of the reasons I picked Pertonix module was so I could easily go back to the original base line if needed for trouble shooting or if parts or replacement became problematic .

68 E-type FHC

Ok, shouldn’t be too hard to nail this. First step is to check all the wiring. Remove the black lead from the coil. Turn the ignition “on”. Touch the " -" side of the coil to any good ground. Hold it for a second and release. Listen for the discharge. If you hear more than one snap, the coil is bad. If it doesn’t motorboat, the ignition module is suspicious.

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Thanks for the process to check Michael. I will check tomorrow

The product is the same David thank you, but there is no mention of my symptoms unfortunately on the site/blog. I have a very powerful spark at the power stroke, it’s the additional weak sparks when ignition is on that’s the problem.

What resistance is the coil?

By the description on the website, it should be 3 ohms, so check that. I’m thinking there’s some capacitance in the primary circuit. Maybe from a poor connection, maybe a defective module.

I did the test this morning. Definitely one snap …and a bright one at that!

Almost certain that your module is the problem

Powerspark have today agreed with you Michael. They are offering me 10% off a new one despite it being new out of the box…just two years since I bought it.

One thing worth trying is to check the grounding. I’m not familiar with this particular trigger, but I suspect it grounds through the breaker plate mount, and then through the distributor body to the block. Try running a wire from any good block ground to the point where the sensor mounts to the plate. Just a temporary run with alligator clips. Turn on the ignition and see if the problem is gone.

What’s the latest? Did you work it out?

I tried that suggestion…same fault unfortunately

Still ongoing Im afraid. Powerspark are not being particularly useful in trying to solve the problem. I have ordered a new distributor (Acuspark) and have also started to refurb the original point distributor as a last throw of the dice

I think going back to baseline(points distributor) is a great next step.

This is what I was hinting at many days ago. Lots of luck.

Latest update…

  1. I fitted a points distributor with the viper coil and leads.
    RESULT: No continual sparking issue
  1. Refitted the powerspark distributor.
    RESULT: continual sparking issue
  1. Disconnected the modulator red (positive) lead from the coil and wired it DIRECTLY to the fuse box for power.
    RESULT: No continual sparking issue.
  1. I then turned the car over to check I had sparking at the power stroke of cylinder 6.
    RESULT: spark on power stroke

With this result, I tried to start the car and it fired and ran perfectly

This proves that the fault lays between the powerspark distributor and the coil. As the modulator was changed and runs from the fuse box and not the coil…it must be the coil causing the issue

Philip, back from vacation
You didn’t mention if it’s a series 1 or 2 car and if there is a ballast in between
All that has to go…
You’ll be cutting spark from 12 to 9
Also did you extend the spark box wires
That also creates resistance
Good luck
I’m not familiar with that set up
But those are common mistakes