Ignition Cuts Out on Front Rotor with RPM Increase...
 

I have my ignition hooked up per Jeff20b's "poor man's direct fire" with three ignitors tripping three coils; one set for each leader, with the coils directly firing the plugs, and one set for both trailers, with the dizzy dispensing the spark to the plugs. The pickups are rewired using shielded cable to the fender where my aluminum ignitor plate is mounted.

The ignition has sounded "froggy" all summer long. When I say "froggy", I just mean the car had power, but in the driveway at anything over 4K, the ignition would randomly sikip a few beats here and there. Checking the plugs showed I was not getting an overly rich mixture to cause this.


I'm in the process of dialing in a Sterling Carb to use as a baseline starting point for a new jetting configuration. I had it screaming the other day- chirpping with every shift thru third.
Yesterday I sprayed some WD-40 on the "not so sparkly clean" mechanical advance part of my dizzy.

Well I went to drive it, and I thought I had blown a seal!
The engine sounded like a plug wire was off.
So I checked everything with the light and found it all to be firing correctly at idle.
Stumped, I tested everything again while operating the Tshaft, and found that the front rotor's spark cuts out intermittantly as I give it fuel, and gets worse with RPM increase until it has NO spark (I'm guessing about 3-4K rpm).

So in the freezing cold, late for a dinner, and trying not to get my dress clothes dirty, I swap out the ignitor for that coil.

No difference!

What could cause this?

I've come to the conclusion that it must be related to my advancing dizzy somehow, as increased RPMs seem to be directly linked.

If the ignitor is good, could the pick-up suddenly not be working at hi-rpm? Perhaps it's the connection at the pickup inside the dizzy. That's where I'm headed next.

But anyone have any other ideas on what would cause this?
Do coils "go bad" in this mannor?

Thanks guys.

Blow out the dizzy with air. I once had the same thing, something is shorting in the dizzy and until it dries it will give you that. At least thats what happend to me, (mine got wet, so I sprayed WD-40 too). Good luck.

I'd suspect a wire or a corroded contact in the cap, but the gap for the leading inductor may need to be adjusted. There really isn't that much to go wrong electrically in the distributor save for the connections.

edit: Just noticed the last part of your post, and yes coils can go bad in that manner. It's called oversaturation, and it basically means that the magnetic field doesn't collapse fast enough. This obviously has more affect as rpms increase.

I've had Hall effect pickups go dead, so it's a possibility. Although in my case, I got no spark whatso ever... Nothing... Nada... (Echoing in my head... "Freebieee..ee..eee" :p: Too much Mon-ster... Monster Garage.)

On the plus side, I ended up with two spare ignitors, which will be staying with me.

Actually, I'm having the same prob with my brothers car. It's a widebody '79 with a streetported 13b w/ 3mm seals, low compression race rotors, To4b turbo, watercooled intercooler, 48IDF throttle body, 750cc primaries, 850cc secondaries, EMS 4424 Stinger computer, 88 distributor, electric fan, pulleys, etc. I've checked everything, and I seem to be having the same problem that Sterling is having. I'm waiting for a 4 coil ignitor module from Australia, and I'm hoping that it'll fix my problem. Any ideas???

I've seen problems in distributors where the bearing on the dist shaft weat out and the gap between the reluctor & stator change at high RPM's.

This problem wrought many hours of diagnostic time trying to figure it out.

I know I take tis for granted as I own a Auto shop but do you have a Scope? The diagnosis would be made a lot quicker that way.

No.
Damn, ya know...I had the opportunity to buy a really old one in mint condition at a garage sale for 10 bucks, and I didn't have cash on me!

Thanks. Thanks for making me relive that "kick myself inthe back of the head" moment, Kehoe! :p:

I will swap out coils tommorow and see.

i am havin same probb... water pump went bad and the gilmer belt that sounds sooo nice flung coolant on my dizzy... but the car is still seeming to be missing bad.. there are two sensors on the dizzy idk what they are for.. hellp me too.

oh yea and my car wont keep an idle it will just die..

you realize this thread is like 7 years old. Are you talking about the ignitors on the side of the dizzy? Post a pic.

no i didnt realize that haha... but yea im talkin about the ignitors.. and i just clean them and nothing changed

Since you have the same question/problem in a different thread I wouldn't post in multiple places. Keep the other thread.